Discover ScienceChemistry                TEXTBOOK
Discover Science: ChemistryTextbookPhilippine Copyright 2012 by DIWA LEARNING SYSTEMS INCAll rights reserved. Printed in t...
Preface    The 21st century is marked by numerous advancements in science and technology. With all theseadvancements, it i...
Table of ContentsUnit I          The Building Block of ScienceChapter 1 Nature of Chemistry .................................
Unit II The World of ChemicalsChapter 6 The Periodic Table ..................................................................
Science Cares ...............................................................................................................
The Building                                                                           UNITBlock of Science IH            ...
Chapter 1                                        Nature of Chemistry          In this chapter, you will be able to    •   ...
Chemistry	can	be	traced	back	to	as	far	as	the	prehistoric	times.	Its	history	and	development	can	be	divided	into	four	peri...
Alchemy	 When	Alexander	the	Great	established	the	Roman	Empire,	ideas	from	the	Greeks	and	those	from	the	Egyptians	came	to...
Traditional Chemistry	 The	period	of	traditional	chemistry,	also	known	as	primitive modern chemistry,	covers	the	end	of	th...
Lesson 2                  Chemistry: Its Role in Science, Technology, and Society                  Word Up	 Search	the	wor...
Science and Its Branches	 Science	has	been	defined	by	different	people	in	different	ways.	Scientists,	teachers,	and	studen...
One	of	the	technologies	that	have	made	a	great	impact	on	many	aspects	of	society	        	Info	Overload	and	people’s	daily...
science.	It	relates	to	many	sciences	that	deal	with	nature,	such	as	physics,	biology,	astronomy,	and	geology.	Since	nature...
Chemistry in Everyday Life 	 Chemistry	touches	practically	every	aspect	of	your	life.		It	is	involved	in	your	essential	ne...
Today,	many	chemists	specialize	in	specific	fields,	such	as	forensic	and	materials	chemistry.		Aforensic chemist	analyzes	...
Foreign Chemists 	 Many	scientists	have	contributed	to	the	development	of	chemistry.	Perhaps	you	can	contribute	to	 chemis...
Amando Kapauan                (4	July	1931	–	12	October	1996)	                He	focused	on	studying	the	effects	of	heavy	...
Lesson 3             The Processes, Tools, and Techniques in Chemistry                 Word Up 	   Name	each	apparatus	and...
Science Process Skills	 As	you	study	chemistry,	you	will	need	the	same	process	skills	that	scientists	use	when	they	work.	...
4.	 Classifying     	 Classification	is	the	process	of	grouping	or	ordering	objects	based	on	observable	traits.	     Objec...
A	bicycle	is	a	two-wheeled	mode	of	                                                transportation.                        ...
10. Designing Experiments     	 Designing	an	experiment	includes	identifying	materials	and	describing	appropriate	steps	in...
Some	things	in	the	laboratory	are	there	not	only	for	learning	but	also	to	   	Info	Overload	maintain	safety.	Safety	always...
help	you.	Do	not	hesitate	to	ask	your	teacher	if	you	have	any	question.     9.	 Return	all	chemicals	and	laboratory	tools	...
Disposal Alert                                          Recycling Alert                         It	tells	you	that	you	    ...
Burette –	is	used	                   Reagent bottle –	is	a	 to	measure	volume	                   storage	vessel	of	 of sol...
Evaporating            Test tube rack –	supports	dish –	is	used	to	     test	tubes.evaporate	liquids.Flame loop –	is	     ...
Iron stand	–                         Wire gauze –	regulates	 supports	the	iron	                   heat	of	the	flame. ring	...
CSI    	 Design	and	make	your	own	laboratory	apparatus.	Demonstrate	its	use	in	class.	Then	fill	out	    the	following	info...
the	rim	of	the	receiving	container.		Pour	the	liquid	down	the	side	to	                                  avoid	spattering	a...
Using a Bunsen Burner	 The	Bunsen	burner	is	used	frequently	in	the	laboratory	as	a	source	of	heat.		It	is	designed	so	that...
When	heating	liquids	in	a	test	tube,	hold	the	tube	with	a	test	tube	       holder	at		45°	and	pass	it	back	and	forth	over	...
4.			 Fold	the	edges	on	the	middle	line	out	over	the	triangles	      made	in	step	3	in	a	straight	line.	5.			 Pull	out	slo...
Chapter Test Choose	the	letter	of	the	correct	answer.			 For	numbers	1–3,	refer	to	the	choices	below: 	 a.		beaker 	 b.		c...
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  1. 1. Discover ScienceChemistry TEXTBOOK
  2. 2. Discover Science: ChemistryTextbookPhilippine Copyright 2012 by DIWA LEARNING SYSTEMS INCAll rights reserved. Printed in the PhilippinesEditorial, design, and layout by University Press of First AsiaNo part of this publication may be reproduced or transmitted in any form or by any means electronic or mechanical,including photocopying, recording, or any information storage and retrieval systems, without permission in writingfrom the copyright owner. Exclusively distributed by DIWA LEARNING SYSTEMS INC 4/F SEDCCO 1 Bldg. 120 Thailand corner Legazpi Streets Legaspi Village, 1229 Makati City, Philippines Tel. No.: (632) 893-8501 * Fax: (632) 817-8700 ISBN 978-971-46-0289-2AuthorsDino F. de Guzman earned his master’s degree in chemical education from the University of the Philippines–Manila. Heobtained his bachelor’s degree in biochemistry and post-baccalaureate degree in teaching education from the University ofthe Philippines–Diliman. Mr. de Guzman is a licensed teacher and has taught science in Claret School, James K InternationalEducation Center, and La Salle Green Hills. He was also a college lecturer at Polytechnic University of the Philippines.Maria Elena G. Delos Reyes obtained her diploma in science education from Philippine Normal University and her cognatein education and bachelor’s degree in chemistry, with distinction, from St. Scholastica’s College. She is also a licensedprofessional teacher and a member of the Association of Science Teachers and Educators of the Philippines and of thePhilippine Association of Chemistry Teachers. Ms. Delos Reyes has taught science and health in grades 3 to 6 at St. AnthonySchool. In high school, she taught integrated science, chemistry, and physics at Cavite School of St. Mark, St. Anthony School,and St. Scholastica’s College–Manila. At present, she works as a home-based writer, editor, and transcriptionist.Allen A. Espinosa is currently completing his thesis requirements for his master’s degree in chemistry education at theUniversity of the Philippines–Diliman. He obtained his bachelor’s degree in secondary education major in chemistry,cum laude, from Philippine Normal University. Mr. Espinosa has taught chemistry at La Salle Green Hills, chemistry andintegrated science at Philippine Institute of Quezon City, and chemistry and physics at Saint Pedro Poveda College. Atpresent, he teaches at Colegio de San Juan de Letran and at De La Salle College of Saint Benilde. Mr. Espinosa is a memberof the Philippine Association of Chemistry Teachers.ConsultantClaribelle J. Bautista finished her doctorate in philosophy in education and her master’s degree in teaching major in chemistryfrom the University of the Philippines–Diliman. She earned her bachelor’s degree in education major in chemistry fromMindanao State University. Dr. Bautista is a licensed teacher and taught mostly chemistry at the high school department ofLourdes School of Mandaluyong, where she also served as a science coordinator and an assistant principal on academics. Sheis the founding president of the Science Educators Association of Mandaluyong.
  3. 3. Preface The 21st century is marked by numerous advancements in science and technology. With all theseadvancements, it is necessary that you are equipped with the basic science and technological skills. Thisbook, Discover Science: Chemistry, is designed to help you acquire the skills you need in the 21stcentury. As you read through the lessons and perform the given activities in this book, you will developyour inventive thinking skills; global awareness; and personal, social, and civic responsibility, amongothers. This book, which has been carefully designed to better facilitate your learning, is composed of the following components: Word Up includes an activity (e.g., word maze, crossword puzzle, etc.) that introduces the important terms you will encounter in the lesson. Sci-Kick displays a comic strip of two characters named Isay and Kiko. These characters will tap your imagination on how the science concept(s) to be learned is evident in real life. CSI (Cool Science Investigation)/Try It Out! presents an experiment/exercise that allows you apply the science concept(s) you have learned in the lesson. Chapter Test includes a 15-item multiple-choice exercise that measures your understanding of the science concepts discussed in a chapter. Science Cares presents an activity that relates the science concepts you have learned in a chapter to different issues concerning the environment and the society. This will make you realize how your knowledge in science can help you become a better citizen. Performance Tasks lists tasks that will allow you to apply what you have learned to various fields of discipline. IP Checkup monitors the progress of your investigatory project (IP) at the end of each unit. A chapter in this book has been solely allocated for you to learn how to construct an investigatory project. Aside from the components given above, some lessons in this book include the following additional sections: Pinoy Science gives an example of a notable Filipino and his or her remarkable contributions to science and technology. Info Overload presents a science trivia related to the science concept discussed in the lesson. May this book help you understand and appreciate chemistry better. Remember that mostscientific discoveries sprouted from a simple question or a little dose of curiosity. Keep on learningand enjoying as you discover the nature of chemistry!
  4. 4. Table of ContentsUnit I The Building Block of ScienceChapter 1 Nature of Chemistry .......................................................................................... 2Lesson 1 The Evolution of Chemistry.................................................................................................2 2 Chemistry: Its Role in Science, Technology, and Society ...................................................6 3 The Processes, Tools, and Techniques in Chemistry .........................................................14Chapter Test .........................................................................................................................................30Science Cares .......................................................................................................................................32Performance Tasks ...............................................................................................................................32Chapter 2 Measurement .................................................................................................... 33Lesson 1 Importance of Measurement ..............................................................................................33 2 Significant Figures .............................................................................................................39 3 Scientific Notation..............................................................................................................44 4 Mass, Volume, Density, and Temperature ..........................................................................48Chapter Test ..........................................................................................................................................54Science Cares ........................................................................................................................................55Performance Tasks ................................................................................................................................55Chapter 3 The Methods of Science ................................................................................... 56Lesson 1 The Scientific Process ........................................................................................................56 2 Investigatory Science Project .............................................................................................60Chapter Test ..........................................................................................................................................71Science Cares ........................................................................................................................................73Performance Tasks ................................................................................................................................73Chapter 4 Matter................................................................................................................ 74Lesson 1 The Nature of Matter..........................................................................................................74 2 Classification of Matter ......................................................................................................79Chapter Test ..........................................................................................................................................89Science Cares ........................................................................................................................................91Performance Tasks ................................................................................................................................91Chapter 5 Understanding the Atom ................................................................................. 92Lesson 1 The Road to Atomic Theory...............................................................................................92 2 Atoms, Isotopes, and Ions ................................................................................................101Chapter Test ........................................................................................................................................108Science Cares ......................................................................................................................................109Performance Tasks ..............................................................................................................................109IP Checkup .......................................................................................................................................... 110
  5. 5. Unit II The World of ChemicalsChapter 6 The Periodic Table ......................................................................................... 114Lesson 1 The Development of the Periodic Table........................................................................... 114 2 Electron Configuration .....................................................................................................121 3 Groups and Periods in the Periodic Table ........................................................................134Chapter Test ........................................................................................................................................143Science Cares ......................................................................................................................................144Performance Tasks ..............................................................................................................................144Chapter 7 Chemical Bonding ............................................................................................ 145Lesson 1 Bond Formation and Molecular Geometry ......................................................................145 2 Molecular Geometry ........................................................................................................157 3 Chemical Nomenclature...................................................................................................165Chapter Test ........................................................................................................................................169Science Cares ......................................................................................................................................170Performance Tasks ..............................................................................................................................170Chapter 8 Chemical Reactions ......................................................................................... 171Lesson 1 Chemical Equations .........................................................................................................171 2 Stoichiometry and Other Calculations .............................................................................181Chapter Test ........................................................................................................................................194Science Cares ......................................................................................................................................195Performance Tasks ..............................................................................................................................196IP Checkup ..........................................................................................................................................196Unit III Gas, Solid, and LiquidChapter 9 Gases ................................................................................................................. 200Lesson 1 Properties of Gases...........................................................................................................200 2 Gas Laws ..........................................................................................................................205Chapter Test ........................................................................................................................................219Science Cares ......................................................................................................................................221Performance Tasks ..............................................................................................................................221Chapter 10 Solids and Liquids .......................................................................................... 222Lesson 1 Nature of Solids and Liquids ...........................................................................................222Lesson 2 Phase Change ...................................................................................................................229Chapter Test ........................................................................................................................................233Science Cares ......................................................................................................................................235Performance Tasks ..............................................................................................................................235Chapter 11 Gases, Solids, and Liquids in Mixtures ........................................................ 236Lesson 1 Nature of Solutions ..........................................................................................................236 2 Colloids ............................................................................................................................247Chapter Test ........................................................................................................................................255
  6. 6. Science Cares ......................................................................................................................................257Performance Tasks ..............................................................................................................................257Chapter 12 Aqueous Solutions .......................................................................................... 258Lesson 1 Oxidation-Reduction Reactions .......................................................................................258 2 Acid-Base Reactions ........................................................................................................269Chapter Test ........................................................................................................................................282Science Cares ......................................................................................................................................283Performance Tasks ..............................................................................................................................283IP Checkup ..........................................................................................................................................284Unit IV Applications of ChemistryChapter 13 Introduction to Nuclear Chemistry .............................................................. 286Lesson 1 Radioactivity ....................................................................................................................286 2 Nuclear Transformation ...................................................................................................297Chapter Test ........................................................................................................................................300Science Cares ......................................................................................................................................302Performance Tasks ..............................................................................................................................302Chapter 14 Introduction to Organic Chemistry ............................................................. 303Lesson 1 Nature of Organic Compounds ........................................................................................303 2 Hydrocarbon Derivatives .................................................................................................314Chapter Test ........................................................................................................................................321Science Cares ......................................................................................................................................323Performance Tasks ..............................................................................................................................323Chapter 15 Introduction to Biochemistry ........................................................................ 324Lesson 1 Biomolecules....................................................................................................................324 2 Metabolism.......................................................................................................................337Chapter Test ........................................................................................................................................339Science Cares ......................................................................................................................................341Performance Tasks ..............................................................................................................................341Chapter 16 Chemistry in Daily Life ................................................................................. 342Lesson 1 Food Chemistry ................................................................................................................342 2 Industrial Chemistry.........................................................................................................347Chapter Test ........................................................................................................................................351Science Cares ......................................................................................................................................352Performance Tasks ..............................................................................................................................353IP Checkup ..........................................................................................................................................353Glossary ..........................................................................................................................................355Bibliography .......................................................................................................................................357Index ..........................................................................................................................................359
  7. 7. The Building UNITBlock of Science IH ave you ever wondered what makes up the things that you use every day such as your clothes, perfume, lotion, pens, and books? Do you want to know how fuel makes power plants and cars run? Do you want to investigate howmedicines, ice cream, and sandwich spread are made? Do you want to know what makes uppaint, insecticides, air fresheners, and fertilizers? Perhaps, you are fascinated with the advancedtechnologies used in forensics, medicine, research, sports, and communication. All of these involvechemistry—the building block of science. This unit invites you to take a look at and experience the wonderful world of chemistry. Youwill discover how chemistry began and developed to improve the quality of people’s lives. You willlearn why chemistry can be considered the building block of all sciences, including biology, physics,and geology. You will be trained to work like a real scientist. You will realize the significance of thedevelopment of atomic theory to the technology you enjoy today.
  8. 8. Chapter 1 Nature of Chemistry In this chapter, you will be able to • trace the historical development of chemistry; • recognize significant contributions of some Filipino and foreign chemists; • explain how chemistry influences science, technology, and society; • explain the nature of different types of matter; • practice safety precautions in using different laboratory apparatus during experiments; • apply rules of significant figures in solving measurement problems; • plan an investigatory project that entails precise and accurate gathering of data; and • appreciate the importance of chemistry in daily life. Lesson 1 The Evolution of Chemistry Word Up Fill in the missing letters to find the term that each statement describes.1. P __ __ __ __ __ A – It is the appropriate combination of ingredients that would cure all diseases.2. A __ __ __ __ __ Y – It is a predecessor of chemistry.3. E __ __ __ __ R of L __ __ E – It is a substance thought to bring immortality.4. M __ __ __ __ __ __ __ M – It is a belief in communication and union with a divine being.5. C __ __ __ __ __ __ __ __ N – It is a process in which fuel reacts with oxygen to produce heat, light, and flame. Sci-kick Do you have any idea why we I think it’s because I guess you’re right! And chemistry live in a modern world today? of the advancement is one of the reasons why of technology. technological advances continue. Discover Science: Chemistry
  9. 9. Chemistry can be traced back to as far as the prehistoric times. Its history and development can be divided into four periods: black magic, alchemy, traditional chemistry, and modern chemistry. Black Magic The period of black magic covers the prehistoric times until the beginning of the Christian era. The ancient people lived in a rough environment where they needed to protect themselves and to find ways of procuring their sustenance. They tried to survive by using what they knew. They discovered how to light a fire even without knowing the chemical principle involved in it. The discovery of fire significantly shaped the early people’s curiosity in controlling chemical changes. People soon found that applying fire to food could change its texture and taste, and that mixing fire with mud could produce hard substances that can contain food. This was how ceramics was Fig. 1.1 Ancient people learned to use fire todiscovered and developed during the Stone Age, the cook food.period prior to 8000 BCE. Ancient civilizations were interested in metallurgy, pottery, and dyes. These crafts were successfully developed in Egypt and Mesopotamia. The discovery of gold in 6000 BCE and copper in 4020 BCE were important breakthroughs in metallurgy. By 2000 BCE, people were producing bronze by heating copper and tin ores together. Bronze was a strong enough material to be used in weapons. Hence, this period is known as the Bronze Age. Around 1500 BCE, the Iron Age emerged when people learned to extract iron from its ore by applying more heat. Iron would combine with carbon during the process, strengthening it and producing steel, a malleable and strong alloy. By 900 BCE theEgyptians were already experimenting with other forms of chemistry, particularly the mummification or the preservation of human bodies with pigments and natural juices. The Greek philosophers first formulated the basic ideas of element and compound from 500 to 300 BCE. Empedocles introduced a theory that all matter is made up of four elemental substances—earth, air, fire, and water—in different proportions. Democritus believed that all materials are made up of indivisible, indestructible, and infinitely small particles which were grouped together in different proportions to form the different materials. He called this indivisible particle atomos, which gave birth to what is presently called atom. Aristotle supported Empedocles’ idea of four elements and Democritus’ idea of the atom. He suggested that there were two pairs of options—hot and cold, moist and dry—which provided the exact nature of matter. He described earth as cold and dry, air as hot and moist, fire as Empedocles Democritus Aristotle hot and dry, and water as cold and moist. Fig. 1.2 The Greek philosophers The Building Block of Science
  10. 10. Alchemy When Alexander the Great established the Roman Empire, ideas from the Greeks and those from the Egyptians came together and were transferred to the Empire. The Arabs came in the 7th century and started al-kimiya. The goal of al-kimiya was to find the following: a. panacea – the appropriate combination of ingredients that would cure all diseases; b. aliksir (later called elixir) of life – the secret potion that would allow a person to be immortal; and c. a way to transform base metals (lead) into gold using the philosopher’s stone. Knights who had joined the crusades brought home the knowledge of al-kimiya from the Arabs to the Europeans. Soon al-kimiya became known as alchemy which some Europeans took up. Despite its growing popularity and use, alchemy was steeped in mysticism and culture that people found it hard to establish the science behind the perceived magic or sorcery. The absence of a defined scientific method made alchemy thrive for a long time. In the 1500s, alchemy was integrated to medicine with the onset of iatrochemistry, in which chemical knowledge was used in treating diseases. Unfortunately, iatrochemistry was still far from the modern chemistry as people today know it because those who practiced iatrochemistry failed to present findings based on a logical scientific experiment. Despite their efforts, alchemists were never able to transmute cheap metals into gold or found the elixir of life. Try It Out! Getting to Know the Alchemists Alchemy has been presented in popular media such as animation and films. Alchemists are often depicted as sorcerers and druids who have magical or supernatural powers. In this activity, you will gain awareness of how alchemists are depicted in several countries. Use science books, encyclopedia, or the Internet to research three alchemists from three different countries. Based on the information you have gathered, create a fictional alchemist. Illustrate your alchemist and make a character profile. The character profile may be in the form of a biodata or narrative. Answer the following questions to guide you in making the character profile of your fictional alchemist. 1. What is the name of your alchemist? 7. What are his or her current alchemy 2. What is his or her gender? projects? Discuss the tools, chemicals, 3. What is his or her nationality? and processes used by your alchemist. 4. How old is he or she? 8. What are his or her discoveries and inventions related to alchemy? 5. What is his or her physical features? Describe briefly his or 6. What is his or her overall personality? her discoveries and inventions. Discover Science: Chemistry
  11. 11. Traditional Chemistry The period of traditional chemistry, also known as primitive modern chemistry, covers the end of the 17th century until the mid-19th century. It is a period of transition from alchemy to modern chemistry. In 1661, Robert Boyle published his book The Sceptical Chymist (The Skeptical Chemist), which focused on the importance of the scientific method. When the scientific method was defined and practiced, it paved the way for experiments and investigations on many scientific queries and problems. This was such a defining period for chemistry. For this, Boyle has been regarded as the father of chemistry. The scientific method was very useful in proving or disproving certain theories during the early years of chemistry. Two German chemists Johann Joachim Becher and Georg Ernst Stahl introduced the phlogiston theory which states that all flammable materials contain phlogiston, a substance without color, odor, taste, or weight that is released in burning. When a substance is burned, phlogiston was supposedly added from the air to the flame of the burning object. In some substances, a product is formed. In 1776, Antoine Laurent Lavoisier disproved the phlogiston theory. He realized that the part of air that combines with substances as they burn was oxygen, the name he gave for “dephlogisticated air.” He recognized the true nature of combustion, discovered oxygen and hydrogen, made the first list of all elements, introduced a new chemical nomenclature (a system of names), helped construct the metric system, and wrote the first modern chemistry textbook Traité Élémentaire de Chimie. The law Fig.1.3 Antoine Laurent of the conservation of mass during chemical reactions was also based on Lavoisier, the father of his discussions. This law states that the masses of the reactants are equal modern chemistry to the masses of the products after a chemical reaction. With his numerous contributions to chemistry, Lavoisier was considered the father of modern chemistry.Modern Chemistry The period of modern chemistry covers the mid-19th century up to the present. In the 1800s, the order and vital understanding of proportions and standards in chemistry came about, causing chemistry to flourish. Inspired by Lavoisier’s works, John Dalton, an English chemist, meteorologist, and physicist, established his atomic theory, which led to further Fig. 1.4 John Daltonadvancements in chemistry—the most significant of which was the creation of the periodic table. The periodic table gave way to a universal classification method of the elements. Many discoveries soon followed such as those involving subatomic particles, chemical bonding, and radioactivity and nuclear reactions. Chemistry has applications to almost everything even to the human body. Constant investigations led to the modern atomic theory, new subatomic particles, and applied chemistry. Technology continues to advance, making chemistry the science as people know it The Building Block of Science
  12. 12. Lesson 2 Chemistry: Its Role in Science, Technology, and Society Word Up Search the word puzzle for the different branches of chemistry listed below. The words may be spelled forward, backward, horizontally, vertically, or diagonally. Use each letter only once. Then look up the meaning of each word in a dictionary. P W L F N T R O W C C F L A R V H V A L E R U I R W O A M H analytical – K C Y Y I I E N N Z N R C H K combinatorial – G U X S A R A R K Q L E I N D food – H I P N I G O X G Y S N T P R P H I V R C O T Q G W S Y S N forensic – W C K O H M A B A X Y I L M K green – V G N O L B P L I N Y C A P I inorganic – Q I S F X V P V S R I N N V Q F C S J H H W O S K Z B A D N medicinal – M E D I C I N A L K B C M O Y organic – Y A N C M P O C O R S K J O B physical – D V N S C K N P B Y Y P S F C polymer – K P R J V F K S L Z R M V U M V U G R E M Y L O P I O V N Q Sci-kick Do you have any idea how important chemistry is to the society? I think chemistry goes hand in hand with technology. Without chemistry, we won’t have the things that we have today like my fave chocolate drink and cake. Discover Science: Chemistry
  13. 13. Science and Its Branches Science has been defined by different people in different ways. Scientists, teachers, and students have their own definitions. Can you give your own definition of science? The word science originated from the Latin word scientia, which means “knowledge.” It is also related to the Latin word scire, which means “to know.” From this, science may be described as something that pertains to knowledge and the process of acquiring this knowledge. How does this definition of science compare with yours? Science is a very big body of knowledge that can be divided into several areas of interest. It can be divided into three main branches: social sciences, mathematics, and natural sciences. Social sciences study human society and social life. Mathematics studies the nature of numbers and explains certain phenomena or situations by using mathematical models. Natural sciences study everything found in nature and may be subdivided into physical sciences and biological sciences.Physical sciences deal with the nonliving component of nature, while biological sciences deal with the living component. Chemistry is a physical science that deals with matter. Technology The word technology came from the Greek word tekhne, which means “art” or “skill,” and logia, which means “the study of.” Thus, technology may be defined as the study of an art or a skill. It is a study of crafting or making things. It can be defined as the use of scientific knowledge or principles to create things that will address people’s needs. It makes life easier and more convenient. Technology is the application of science. Technology can be classified into products and processes. A technological product is an object or infrastructure that helps people in their daily tasks. Tools, machines, gadgets, and buildings are technological products. A technological process is a system or a set of procedures that people can use to enhance their skills and talents or to be more efficient in their work. Fermentation, food preservation, and water purification are technological processes. Can you give other examples for each type of technology? Ideally, technology should always benefit humanity. However, the disadvantages of some technology may outweigh their advantages. Using such technology may be detrimental both to human lives and the environment in the long run. Moreover, some people may use technology for personal gains rather than for the common good. Try It Out! Modern Technology: Is It In or Out? Research three technologies from three different countries. Complete the table below and share it with the class. Technology: _________________________ Creator Features Advantages Disadvantages Good or Bad Reasons The Building Block of Science
  14. 14. One of the technologies that have made a great impact on many aspects of society Info Overload and people’s daily lives is the computer. People can now do many things that were Will there ever be a time when people are not possible or quite difficult to do years replaced with artificial intelligence (AI)? With ago without computers. Moreover, with computers continuously being improved, some the availability of the Internet, there is a people may think that the day will come that AI surge of information and global awareness. ultimately replace human beings. In chess, AI has The use of Internet made communication been employed in creating a computer program and interaction among scientists and named Deep Fritz, which defeated Vladimir researchers faster and easier. They can Kramnik, a world champion in chess, in 2006. share information with each other and seek Deep Fritz is an improvement of other chess advice or assistance in research from each programs created in the 1980s and 1990s. other. Can you give other advantages of The AIs for chess, which included Deep Blue and the Internet? Deep Thought, have the word “deep” in their names In your study of chemistry, you as influenced by the novel The Hitchhiker’s Guidewill appreciate the use of information to the Galaxy. In the novel, an ultimate thinking technology. You may find the Internet computer named “Deep Thought” was made to to be a great source of information and answer the ultimate questions on life, the universe, a valuable tool in your study. However, among other things.not everything you find in the Web is AI has raised ethical issues and has been a true or accurate. Some Web content have topic of debate about the future of technology and very little credibility, while some are society. The use of computers, machines, and mere opinions. Thus, you must be able to robots with artificial intelligence has advantages and evaluate the information that you obtain. disadvantages. But one thing is certain, AI can never As a science student, you are mainly replace humans. Advanced technologies are concerned with accurate and validated created by people to make their work easier information and knowledge. and not to replace them.Etymology of Chemistry The word chemistry has a number of origins. It may have come from the Greek word khemeia, which means “metalworking.” It may have originated from the Arab word al-kimiya, which can be interpreted in several ways. Al-kimiya can be taken to mean Egyptian science, noting that Egypt was called kem-it. It was during their conquest of Egypt that Arabs came to know this type of knowledge. It may have originated from the Greek word khymeia, which means “the art of melting metals and alloy production.” In 1530, Georg Agricola, a humanist, suggested to drop “al-” from the Arabic word al-kimiya, and return it to its classical root chymia and chymista instead of the earlier alchymiaand alchymista. This was then adopted and translated in French as chimie; in German as chemie; inItalian as chimica; and in English as chemistry. Chemistry and Its Branches Chemistry is a physical science that can be defined as the study of matter and its composition and structure, the changes it undergoes, and the energy associated with these changes. It consists of many specialized fields and interacts with all other areas of science. Hence, it is considered a central Discover Science: Chemistry
  15. 15. science. It relates to many sciences that deal with nature, such as physics, biology, astronomy, and geology. Since nature is made up of matter, then everything in nature may be explained and further investigated using chemistry. Thus, chemistry can be integrated with all the other sciences, leading to the formation of its different branches such as the following: 1. Inorganic chemistry – is the study of the chemical nature of the elements and their compounds not containing carbon and that are not organic. Examples of such substances are minerals found in Earth’s crust and nonliving matter. 2. Organic chemistry – is the study of compounds consisting largely of hydrocarbons (compounds containing hydrogen and carbon), which provide the parent material for all other organic compounds. Carbon is studied separately because of its unique sharing properties which allow it to form rings and long branched chains, producing hundreds of thousands of carbon-based molecules. Organic compounds are particularly important because they make up the majority of compounds in living organisms. 3. Physical chemistry – deals with the application of physical laws to chemical systems and chemical change. It is concerned with the role of energy in chemical reactions. 4. Analytical chemistry – deals with the qualitative and quantitative determination of chemical components of substances. 5. Biochemistry – is the chemistry of living organisms and life processes. It is concerned with the composition and changes in the formation of living species. 6. Geochemistry – is the application of chemistry to processes taking place on Earth, such as mineral formation, metamorphosis of rocks, and formation and migration of petroleum. 7. Radiochemistry – is the study of the chemical effects of high-energy radiation and the behavior of radioactive isotopes, atoms of the same element that vary in the number of neutrons they have. 8. Macromolecular chemistry or polymer chemistry – deals with the chemical synthesis and chemical properties of polymers. 9. Environmental chemistry – is the study of the chemical and biochemical phenomena that occur in natural places. 10. Green chemistry – is the study of the design of chemical products and processes that reduce or eliminate the generation and use of hazardous substances. 11. Electrochemistry – is the study of the reactions that can take place at the interface of an electronic conductor and an ionic conductor (an electrolyte). 12. hotochemistry – is the study of the interaction of light and chemicals. P 13. Astrochemistry – is the study of the composition and reactions of chemicals found in stars and in space, as well as the interactions between matter and radiation. 14. Food chemistry – is the study of the chemical processes in food. 15. Medicinal chemistry – is the study of the applications of chemistry to pharmacology and medicine. 16. Forensics chemistry – is the study of the application of chemistry to law enforcement. It involves chemical analysis of substances that may have been used in a crime scene. 17. Combinatorial chemistry – is the study of synthesizing substances quickly and inexpensively using innovative methods. The Building Block of Science
  16. 16. Chemistry in Everyday Life Chemistry touches practically every aspect of your life. It is involved in your essential needs, such as food, shelter, clothing, energy, and clean environment. Everything in this world is made up of chemicals. Your body is made up of different elements such as hydrogen, oxygen, carbon, nitrogen, and other elements. Your different body systems involve different chemicals and chemical reactions. Digestion is a chemical process that helps your body get the essential nutrients from the food you eat. These nutrients are carried by your blood to various parts of your body to build new cells and produce energy for your daily activities. Respiration is another chemical process by which glucose is broken down and oxidized to provide energy. It also explains what happens to oxygen when you breathe and why carbon dioxide is released when you exhale. It can be summarized in the following equation: C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy glucose oxygen carbon dioxide water Recall how plants produce their own food through photosynthesis, a process important for the survival of people and animals. Plants give off oxygen that people and animals need to live. The chemical reaction of photosynthesis can be summarized by the following equation: 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2 Can you think of other chemical reactions happening in your daily life? Chemistry and the Society Chemistry improves the quality of people’s lives in various ways. It provides people with new products and processes to satisfy their needs and solve problems in health, resources, and environment. Researches in chemicals led to the discovery and development of synthetic fibers, paints, adhesives, drugs, cosmetics, electronic components, lubricants, and thousands of other products. They also led to the development of processes, such as improved oil refining and petrochemical processing that save energy and reduce pollution. Researches on the chemistry of living things spur advances in medicine, agriculture, food processing, and other fields. In medicine, advanced medical equipment and new drugs are constantly being developed to provide more accurate diagnosis, monitoring, and treatment of diseases. These include computed tomography (CT) scanners, magnetic resonance imaging (MRI) machines, positron emission tomography (PET), and laser-assisted in situ keratomileusis (LASIK) surgical machines. Chemists respond to the needs of the increasing human population. Agrichemists look for ways to make crops more tolerant to certain pests and herbicides; improve the taste and color, and promote longer shelf life of fruits and vegetables; and improve the quality of plants to yield more and better crops. The use of computers to analyze complex data opened the door to combinatorial chemistry. A combinatorial robotic system can produce thousands or millions of compounds in a year against 100 to 200 compounds that traditional chemists can produce. Aside from sequencing of human genes and production of new drugs, combinatorial chemists also now apply combinatorial chemistry to other fields such as semiconductors, superconductors, catalysts, and polymers. 10 Discover Science: Chemistry
  17. 17. Today, many chemists specialize in specific fields, such as forensic and materials chemistry. Aforensic chemist analyzes pieces of evidence gathered from crime scenes. They run tests on a piece of evidence and reach a conclusion based on the results of these tests. Identifying pieces of evidence is an important part of the larger process of solving a crime. This helps solve crime faster and more accurately. A materials chemist studies and develops new materials to improve existing products or make new ones. Try It Out! Chemicals Everywhere Identify at least three chemicals you can find in each place listed below. Write the uses of each chemical. C - church H - ospital E - nvironment M - arket I - ndustry S - chool T - ransportation R - estaurant Y - our homeChemists and Their Tasks Chemists are scientists who seek and apply new knowledge about chemicals. They are the experts in chemical reactions, chemical products, and chemical processes. They conduct scientific researches, analyze substances, and synthesize new substances. They are needed in other fields such as engineering, medicine, education, business, culinary arts, nutrition, sports, and computer technology. Some of the tasks of a chemist are as follows: 1. Analyze different chemicals such as their physical properties, composition, structure, and reactions using varied techniques 2. Design, develop, and customize different products and processes 3. Conduct tests and researches to determine the validity of a process or equipment and to develop or improve new products 4. Prepare different chemicals for experiments, production of new materials, and other industrial and research purposes 5. Communicate with other scientists to share information, seek advice, criticize research works, and develop researches 6. Write research papers to have a record of study conducted for reference and further research The Building Block of Science 11
  18. 18. Foreign Chemists Many scientists have contributed to the development of chemistry. Perhaps you can contribute to chemistry as they did especially if you decide to specialize in this field. Jöns Jacob Berzelius (20 August 1779 – 7 August 1848) He formulated the law of constant proportions, which states that inorganic substances are composed of different elements in constant proportions by weight. He discovered the elements silicon, selenium, thorium, and cerium. He was credited for originating the chemical terms catalysis, polymer, isomer, and allotrope. Friedrich Wöhler (31 July1800 – 23 September 1882) He contributed to the development of organic chemistry by synthesizing urea in the laboratory. He also discovered several elements. Gilbert Newton Lewis (23 October 1875 – 23 March 1946) He contributed to the understanding of the covalent bond and chemical thermodynamics. Glenn T. Seaborg (19 April 1912 – 25 February 1999) He discovered 10 transuranium elements, namely, plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium, and seaborgium. Roy J. Plunkett (26 June 1910 – 12 May 1994) He accidentally invented Teflon (the DuPont trademark name for polytetrafluoroethylene or PTFE). Teflon is nonstick coated cookware. Filipino Chemists Here are some Filipino chemists and their respective contributions to chemistry: Anacleto del Rosario (13 July 1860 – 2 May 1895) He studied producing a pure kind of alcohol from tuba of nipa palm. He is regarded as the father of Philippine science and laboratory. Julian Banzon (25 March 1908 – 13 September 1988) He researched on the different methods to produce alternative fuel.1 Discover Science: Chemistry
  19. 19. Amando Kapauan (4 July 1931 – 12 October 1996) He focused on studying the effects of heavy metals in our environment. Baldomero Olivera (1941 – present) He discovered cone snail toxins or conotoxins. He discovered ziconotide (Prialt), a pain reliever used for chronic, intractable pain for people with cancer, AIDS, or certain neurological disorders. Try It Out! An Interview with a Chemist Ask your relatives and friends if they know a chemist working in the Philippines. If not, search the Internet or look up a telephone directory for companies related to chemistry. Look for a chemist and set up an appointment for a face-to-face interview, if possible. If not, get his or her e-mail address and interview him or her via e-mail or chat. Supply the information listed below. Share your work with the class. 1. Name 2. Age 3. Educational background 4. Name of company and location 5. Position and nature of workBased on your interviewee’s responses, answer the following briefly. 1. Would you consider becoming a chemist someday? Why? ________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ 2. What are the possible jobs offered to chemists in the Philippines? __________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ 3. Are Filipino chemists contributing to our country’s development? __________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ The Building Block of Science 1
  20. 20. Lesson 3 The Processes, Tools, and Techniques in Chemistry Word Up Name each apparatus and write your answer in each box. Sci-kick What do you have there with I’ve borrowed some tools. you, Kiko? I have to finish my science project at home.1 Discover Science: Chemistry
  21. 21. Science Process Skills As you study chemistry, you will need the same process skills that scientists use when they work. Science process skills are the tools you need to understand the mechanisms of the material world. A scientifically literate person uses them in solving problems, making decisions, and understanding further the society and the environment. Developing these skills will allow you to think creatively and critically and help you satisfy your curiosity. 1. Observing Observation is the most fundamental of all the processes. When you observe, you gather information through the use of one or more of your senses (or instruments that extend our senses): sight, hearing, touch, taste, and smell. Observation is influenced by your past experiences. It often involves instruments and requires careful recording and description. Surprising or unexpected observations occasionally contribute Fig. 1.5 A scientist working in the laboratory new and important knowledge. The gathered information or observations are called data or facts. An observation may be qualitative or quantitative. A qualitative observation involves using as many senses as possible. It describes an object, a situation, or an event using only words. A quantitative observation makes use of numbers, as well as words, in the description of an object, a situation, or an event. Tools or devices are used to measure the characteristic being described. Based on Figure 1.5, the scientist may have the following observations: Qualitative Quantitative 1. Each test tube contains a small 1. There are five test tubes in the rack. amount of liquid. 2. The first test tube contains a clear liquid. 2. The third test tube contains 3 mL of green ink.2. Measuring Measuring is comparing an unknown quantity with a known standard of reference. Measurements are to be recorded systematically with labeled units of measure. They should be precise and accurate. Length, volume, mass, temperature, time intervals, and force are common quantities that are measured. 3. Inferring An inference is an explanation of an observation in terms of a previous experience. Inferring is a process skill which allows you to blend your unique interpretation with your observations. In science, inferences about how things work are continually constructed, modified, and even rejected based on new observations. For example, a student who observed a white spot on his or her black shirt may infer that his or her mother used bleach in washing his or her clothes. The Building Block of Science 1
  22. 22. 4. Classifying Classification is the process of grouping or ordering objects based on observable traits. Objects that share a given characteristic can be said to belong to the same set. Classifying involves grouping objects, concepts, or events based on observable properties to show similarities, differences, and interrelationships. Waste segregation is an example of classification. 5. Predicting Predicting is forming an idea of a future occurrence based on observations and inferences. A prediction may be used to generalize that under a certain set of circumstances, a certain outcome may be expected. It may be used to describe outcomes beyond the observed data. For example, you are collecting data on the temperature of water. If the readings are 30°C, 32°C, 34°C for 3 minutes, you can predict that after 5 minutes of heating, the temperature of water will be 38°C. This is called interpolation. In interpolating, predictions are made within the range of given data. 6. Communicating Communicating is the process of organizing and processing data using words, symbols, or graphics to describe an object, a situation, or an event. A scientist is obliged to make the information available to the community for independent confirmation and testing. Scientists disseminate the results of their studies in journals, scientific meetings, seminars, and informal networks. This dissemination contributes to the common core of knowledge of the past and provides the vehicle for continuous review of this body of knowledge and for advancements in science. 7. Hypothesizing Hypothesizing is stating the proposed solutions or expected outcomes for your investigations or experiments. It is an intrinsic and creative mental process. A hypothesis shows the expected relationship between two variables in an attempt to explain a cause-and-effect relationship. It should be testable. It is tested to help explain observations that have been made. It is often stated as an “if and then statement.” An example of a hypothesis is “If salt is added to water, then it will boil faster.” 8. Defining Operationally To define operationally is to describe objects in the context of a common experience. An operational definition tells one what to do to or with an object and what to observe as a result of the action. It is written in terms of how an object works or how it can be used. Examples of operational definitions are given below: Object Operational Definition A ruler is a tool that measures the length of an object.1 Discover Science: Chemistry
  23. 23. A bicycle is a two-wheeled mode of transportation. A bicycle can move a person from one place to another. A pen is a tool for writing.9. Controlling Variables A variable is a changeable factor that can affect an experiment. Controlling variables involves deciding which variables or factors will influence the outcome of an experiment, situation, or event, and deliberately controlling them systematically. Note how important it is to change only the variable being tested and keep the other variables constant. If you allow more than one variable to be changed, you cannot determine the cause of the changes you observe in the independent variable. The variable you plan to experiment with is the manipulated or independent variable, while the one being measured to determine its response is the responding or dependent variable. The variables that you control or made the same in your experiment are the constant variables. (a) control (b) experimental Fig. 1.6 The effect of salt on the boiling temperature of water Many experiments have a control variable, which is a treatment that you can compare with the results of your test groups. In the experiment on the temperature of hot water upon the addition of salt, everything should be the same except the presence of salt. The beaker, the amount of water, and other materials should be the same. The setup in which salt is not added (setup A) is the control. The setup in which two tablespoons of salt is added (setup B) is the experimental or test group. In this experiment, salt is the independent variable, temperature is the dependent variable, and all the rest of the materials are the constant variables. The use of experimental and control setups are only two ways of controlling variables. The Building Block of Science 1
  24. 24. 10. Designing Experiments Designing an experiment includes identifying materials and describing appropriate steps in a procedure to test a hypothesis. A procedure is the plan that you follow in your experiment. It includes the materials needed and how to use them. 11. Experimenting Experimenting is carrying out an experiment by carefully following the steps in the procedure so that the results can be verified by repeating the procedure several times. 12. Acquiring and Organizing Data Acquiring data is the process of collecting qualitative and quantitative observations. Data can be organized in several ways such as using tables and graphs. 13. Interpreting Data Interpreting data involves analyzing, synthesizing, and evaluating trends or patterns in a set of data. These patterns may be used to formulate hypotheses, make predictions, and draw generalizations. Interpretation requires creative thinking that can result in a whole idea that encompasses the data. 14. Identifying Cause-and-effect Relationship Identifying causes and effects requires analytical thought as one seeks to distinguish cause from effect. The cause always happens before the effect. The effect is a result. You identify cause-and-effect relationships every day when you solve problems and make decisions. Learning to identify cause-and-effect relationships can help you understand what has happened. 15. Formulating Models Formulating models includes describing or constructing physical, verbal, mental, or mathematical explanations of systems and interconnected phenomena that cannot be directly observed. A model is used to simplify processes or structures. The Chemistry Laboratory Chemists need a place to conduct experiments and researches, and the laboratory is the ideal venue. Many chemical products have been synthesized and various chemicals have been discovered in laboratories. For a chemistry student, a laboratory is where you will apply the different chemical principles that you will learn. Safety in the Laboratory Actual participation in the laboratory work is essential in the study of chemistry. Ideally, a chemistry laboratory should have the following: (a) ventilation system, (b) sink, (c) work table, (d) gas and water outlets, (e) trash bin, (f) fire extinguisher, (g) first aid box, (h) board for writing, (i) cabinets for storage, and (j) fume hood. However, a laboratory may not have all of these things. If that is the case, then certain experiments cannot be carried out in the laboratory. 1 Discover Science: Chemistry
  25. 25. Some things in the laboratory are there not only for learning but also to Info Overload maintain safety. Safety always comes first. In the chemistry laboratory, you Fire is the most common serious hazard in a typical will be working with an equipment or chemistry laboratory. While proper procedure and a material that may cause accidents if training can minimize the chances of an accidental fire, not handled properly. Accidents do you must still be prepared to deal with a fire emergency. happen; that is why every precaution The different classes of fire are as follows:must be taken to prevent them. Follow • Class A – ordinary combustibles (wood, paper, the basic safety rules while working in plastics)the laboratory. • Class B – flammable and combustible liquids • Class C – flammable gases 1. Always follow your teacher’s • Class D – combustible metals instructions. Listen intently • Class E – electrically energized equipment and make sure that you • Class F – cooking oils and fats understand everything that you have to do. Prepare Fire extinguishers are color coded so that you everything you need. can identify them quickly and use the right type of 2. Take only the materials that extinguisher for a certain class of fire. The two most you are asked to bring to common types of extinguishers in the chemistry the laboratory. Remember laboratory are pressurized dry chemical and carbon that food and drinks are not dioxide extinguishers. Dry chemical extinguishers are allowed inside the laboratory. useful for class ABC fires, and hence, a better choice for the chemistry laboratory. They leave a blanket of 3. Avoid playing inside the nonflammable material on the extinguished material, laboratory. which reduces the likelihood of reigniting. Carbon 4. Handle chemicals with dioxide extinguishers, on the other hand, are most caution. Dispose of chemical effective on class B and C fires. They do not work wastes and other wastes very well on class A fires because the material usually properly. reignites. They do not leave harmful residue. Since the 5. Use all laboratory tools gas disperses quickly, carbon dioxide extinguishers properly. Handle them with are only effective from 3 to 8 feet. A carbon dioxide care to avoid breakage. Check extinguisher is a good choice for an electrical fire their conditions before you involving a computer or other delicate instrument. It is use them. not suitable for outdoor use. 6. Do not deviate from the An easy acronym on using fire extinguishers is PASS: experimental procedures. Pull the pin that keeps the handle from being accidentally 7. Wear protective clothing such pressed. The pin is located at the top of the extinguisher. as a laboratory gown, and use protective gadgets such as Aim the nozzle toward the base of the fire. Remember to goggles, masks, and gloves, stand approximately 8 feet away from the fire. if necessary. If you have long Squeeze the handle to discharge the extinguisher. Once hair, tie it back or wear a you release the handle, the discharge will stop. hairnet. Sweep the nozzle back and forth at the base of the fire. 8. Report any injury or any After the fire appears to be out, watch carefully for untoward incident to your possibility of reignition. teacher who is always there to The Building Block of Science 1
  26. 26. help you. Do not hesitate to ask your teacher if you have any question. 9. Return all chemicals and laboratory tools to the stock room or storage area. Do not take home any chemical or laboratory tool. 10. Refrain from using cell phones and other electronic gadgets in the laboratory. Remove all pieces of jewelry while working in the laboratory. 11. Wash your hands after handling chemicals. Clean also the laboratory materials that you have used. 12. Do not play with chemicals and fire. Never taste any substance in the laboratory unless you are told to do so. 13. Learn how to put out fire. Your teacher will demonstrate how to use the fire extinguisher if the laboratory has one. 14. If acid is spilled on your skin, wash it with running water and sodium carbonate. Wash it again with water afterward. 15. If a base is spilled on your skin, wash it with water and then with 1% acetic acid solution. Wash again with water afterward. Safety Symbols Safety symbols are used in the laboratory to emphasize specific types of precautions. They are used as aids to communicate information on hazards and the need for personal protective paraphernalia, and give guidance and instruction in case of emergency. Remember to take the necessary precaution when you see safety symbols. Safety Clothing Eye Safety It reminds you to wear It appears when a your laboratory gown danger to the eye properly. A laboratory exists. You should gown protects your wear safety goggles skin and your clothes when you see this from any kind of spills. symbol. Chemical Safety Fire Safety It reminds you that the It reminds you that the chemicals you use are chemical you use is corrosive. Corrosive flammable. This also materials are usually reminds you that care strong acids or bases. should be taken around They can cause burns open flames. on your skin. Thermal Safety Explosion Safety It reminds you to use It reminds you that the caution when handling misuse of chemicals hot objects. can cause an explosion.0 Discover Science: Chemistry
  27. 27. Disposal Alert Recycling Alert It tells you that you It reminds you that the can discard the materials can be stored chemicals down the and recycled. drain. Electrical Safety Hygiene Safety It reminds you that It reminds you to wash care should be taken your hands thoroughly. when using electrical equipment. Poison Safety Dispose Alerts It indicates the It reminds you to throw presence of a toxic or use chemicals and poisonous material. materials in the proper disposal area.Laboratory Tools Chemistry involves laboratory investigations. You must know the basic apparatus used in chemistry to ensure that your investigations proceed smoothly. The following are the common tools that you will use in the laboratory: Alcohol burner – is Stirring rod – is used for a source of heat. stirring substances and transferring liquids to another container. Beaker – is used to Pipette bulb or aspirator contain liquids. – is used to clean the pans of platform balance and get liquid using a pipette. Bunsen burner – is Platform balance – is a source of heat. used to measure the mass of a substance. The Building Block of Science 1
  28. 28. Burette – is used Reagent bottle – is a to measure volume storage vessel of of solutions during chemicals. titration. Ceramic square – Rubber stopper – supports hot supports thermometer apparatus to and covers the openings prevent breakage. of narrow-mouthed containers. Clay triangle – Rubber tubing – connects supports a crucible. a Bunsen burner to a gas outlet. Crucible tongs – is Test tube brush – is used used to hold a to clean the test tubes. crucible and its cover. Double burette Erlenmeyer flask – is clamp – supports used to contain liquids. burette during titration. Test tube clamp or Test tube holder – is used utility clamp – to hold a test tube. supports the test tube and burette. Discover Science: Chemistry
  29. 29. Evaporating Test tube rack – supports dish – is used to test tubes.evaporate liquids.Flame loop – is Thermometer – is used toused to hold measure temperature.chemicals during flame test.Florence flask – is Triple beam balance – used to boil is used to measure mass liquid solutions. of a substance.Forceps – is used Tripod – supports the to get small clay triangle or wire objects. gauze.Funnel – is used to Volumetric flask – is used transfer liquids to to measure volume of another container liquids.and support filter paper during filtration.Graduated cylinder Wash bottle – is used to – is used to wash the inner sides of measure volume of the apparatus.liquids.Iron ring – Watch glass – is a supports the wire container used to observe gauze or clay small specimens.triangle. The Building Block of Science
  30. 30. Iron stand – Wire gauze – regulates supports the iron heat of the flame. ring or clamp. Dropper pipette Spot plate – is a reaction or dropper – is vessel used for small used to transfer amounts of substances, small amounts of especially when using liquids to another litmus paper. container. Mortar and Spatula – is used for pestle – is used getting solid chemicals for pounding or from reagent bottles. grinding solid chemicals to powder form. Crucible and cover Fish tail – is used for – is a vessel used spreading the flame of in heating small Bunsen burner. amounts of solid substances at high temperature. Bell jar – is used Glass tubing delivery to cover and store tubes – is used to make volatile chemicals. droppers for capillary tubes. Desiccator – is Syringe – is used for used for removing sucking and expelling the moisture from liquid in fine stream. specimens. Measuring pipette Transfer pipette – is used – measures exact to transfer liquids. volume of liquids. Discover Science: Chemistry
  31. 31. CSI Design and make your own laboratory apparatus. Demonstrate its use in class. Then fill out the following information: Name of laboratory apparatus: Use: Materials and cost: How it looks like: How it works: Laboratory Techniques Conducting an experiment is the best way to learn chemistry. Poor results in a chemistry experiment are often the result of poor laboratory techniques. A laboratory technique is not random, but a rational approach to a problem. The most common errors in a chemistry experiment are chemical contamination, the loss of precipitates, spilled liquids, and the like. To avoid these errors, you must practice good basic laboratory techniques. Using Chemicals Chemicals are stored in reagent bottles. Always read the label on a reagent bottle before using its contents. Remove the lid and place it on top of the table upside down. Get only the desired amount of the chemical you need. Never touch a chemical with your hands. Use a spatula for solids and a dropper for liquids.1. Solids To obtain a solid, remove the lid or stopper and place it upside down on the table. Rotate and tilt the bottle at the same time to dispense the solid slowly to a clean dry beaker. You can also use a clean dry spatula to spoon out a small amount of the solid chemical. If the container has a narrow mouth like that of a test tube, use a folded or rolled paper, then gently tap the paper to transfer its content into the test tube. 2. Liquids To obtain a liquid from a reagent bottle, grasp the vertical flange between your third and fourth fingers, palms up. Holding the flange this way, bring the neck of the bottle in contact with The Building Block of Science
  32. 32. the rim of the receiving container. Pour the liquid down the side to avoid spattering and spilling. Replace the flange when finished. Note: The flange must never touch the laboratory countertop or the side of the receiving container to avoid contamination. To transfer a liquid using a pipette, use an aspirator to avoid contamination. Place an aspirator on top of the pipette as illustrated. Compress the aspirator. Slowly release pressure so that the liquid is drawn into the pipette. Remove the aspirator and simultaneously place your index finger over the end of the pipette. Insert the tip of the pipette into the receiving container. Hold it vertically and allow pipette to drain freely. Liquids can also be transferred with the use of a stirring rod. Pour liquids into another container using a glass rod in an upright position of the receiving container. In obtaining liquids from bottles equipped with medicine dropper, be sure that it never touches both the container and the contents of the receiving vessel. Measuring Liquids The graduated cylinder and pipette are two commonly used devices for measuring liquid volumes. Study carefully the particular device to determine how it is calibrated and how to use it to measure liquids accurately. When reading the level of liquid in any liquid measuring device, read the bottom of the meniscus (lowest portion of the convex dip of the liquid as it sits in the graduated cylinder), with your eye at the same level as the liquid surface. Using the Laboratory Thermometer Never shake a laboratory thermometer. Immerse the bulb of the thermometer in the substance whose temperature you are measuring. Allow the alcohol level to stabilize and read the thermometer. Be sure to study the calibrations on the thermometer to determine how it can be read accurately.Do not use a thermometer as a stirring rod for solutions. Remember that the bulb of the thermometer is delicate. If a thermometer breaks, immediately inform your teacher. Discover Science: Chemistry
  33. 33. Using a Bunsen Burner The Bunsen burner is used frequently in the laboratory as a source of heat. It is designed so that gaseous fuel may be mixed with the correct barrelamount of air to yield the maximum amount of heat. It can produce three different types of flames: safety flame, blue flame, and roaring blue flame. 1. Safety flame – It is yellow or orange in color. It is the coolest flame, air hole approximately 300°C. It is the flame produced when air holes are gas inlet closed. It is used only to show that the Bunsen burner is on and not for heating. 2. Blue flame – It is also called medium flame, nonluminous flame, or invisible flame. It is approximately 500°C. It is the most commonly used flame. 3. Roaring blue flame – It is the hottest flame, approximately 700°C. It is characterized by a light blue triangle in the middle. It is so- base named because it makes a roaring sound. The correct steps in setting up and operating the Bunsen burner safely and appropriately are as follows: 1. Connect the Bunsen burner to the gas supply using a rubber tubing. 2. Completely close the air holes. 3. Turn the gas valve on the gas outlet to the fully open position. 4. Light the burner by holding a match to the side of the mouth of the burner. If you stick the match in the middle of the gas stream, the flame is usually blown out before the burner lights. 5. Open the air holes slowly to admit more air into the flame and produce a light blue flame. Adjust the air holes and gas supply to produce the desired size of flame. 6. Turn the burner off at the main gas supply valve when done.Heating Solids and Liquids1. Solids To heat solids in a test tube, clamp the tube to an iron stand at 45°. The flame is passed slowly back and forth along the bottom of the tube. Solids may be heated to high temperatures in a crucible supported by a clay triangle over an iron ring or tripod. The crucible is carefully placed on a clay triangle either at upright position or at a certain angle.2. Liquids When heating liquids in a beaker, place it over a wire gauze supported by an iron ring attached to an iron stand. The wire gauze distributes the heat evenly and prevents cracking of the container due to sudden temperature changes. During heating, stir the liquid while carefully heating to avoid lumping. Uneven boiling can cause the dangerous spattering of large quantities of hot liquid. The Building Block of Science
  34. 34. When heating liquids in a test tube, hold the tube with a test tube holder at 45° and pass it back and forth over the flame of a burner. The test tube should be heated just below the liquid level, but never at the bottom of the tube. (Note: Heat the tube with the open end pointed away from you and from anyone else. Never heat the tube directly at the bottom, the contents may be ejected suddenly due to superheating. Never boil a liquid in a tube, which is more than a quarter full.)Measuring Mass The balance is an instrument used for determining the mass of a substance. panAmong the various types of laboratory ridersbalances, the most commonly used is the triple beam balance, although top-loading digital balances are becoming popular. In carrying the balance, place one hand under the base and the other hand on the arm. Be sure that all riders are back to the zero point. beams adjustment To measure the mass of a substance, screw base armthe pointer must be at the zero scale. Put all riders at the zero point. If the pointer is not in exact balance, use the adjustment screw to point it back to the zero mark. Never put chemicals directly on the balance pan. Use a paper box or a clean and dry empty container. Get the mass of the paper box or container before adding the chemicals. Once you have placed the object to be weighed on the pan, move the riders along the beams beginning with the largest mass first. Make sure all riders are in a notch before you take a reading. Return all the riders to zero point after weighing. Always keep the balance clean. CSI Creating a Paper Box 1. Fold the paper in half, then extend it back out. Fold each half inward again to end up in the middle line. (1) 2. Turn the paper sideways and repeat step 1. However, after the second fold, fold back out again and straighten the paper. 3. Fold the four corners inward, but do (2) not exceed the lines from the second (3) fold in step 2. Make sure not to fold in more than a third of the width. Discover Science: Chemistry
  35. 35. 4. Fold the edges on the middle line out over the triangles made in step 3 in a straight line. 5. Pull out slowly both sides over the middle line, (4) strengthening the edges and corners as you proceed. Make sure that the corners are strong and forming 90°. (5) Using the Platform BalanceObjectives:1. Manipulate the platform balance correctly.2. Compare the mass of a cup of sand with a cup of salt.Materials: platform balance, salt, sand, measuring cup, set of weightsProcedure:1. Use the paper box you made. Place it on the left pan of the platform balance. Determine the mass of the paper box by moving the riders until the pointer reaches the point. Record the mass in the data table.2. Put 1 cup of sand in the paper box. Bring the pointer to the zero mark. Record the mass in the data table.3. Make another paper box and determine its mass. Record the mass in the data table.4. Put 1 cup of salt in the paper box and determine its mass. Record the mass in the data table. Data Table Sand Salt Mass of paper box Mass of paper box + sample Mass of sampleQuestions:1. Why should you determine the rest point of a platform balance before getting the mass of a sample? 2. What are the possible causes of error in weighing?3. Which is heavier: a cup of salt or a cup of sand? Why? The Building Block of Science
  36. 36. Chapter Test Choose the letter of the correct answer. For numbers 1–3, refer to the choices below: a. beaker b. crucible and cover c. graduated cylinder d. test tube 1. It is a deep, wide-mouthed, thin-walled, and cylindrical device with a spout. 2. It is a container made of porcelain and is used for heating substances that requires extreme heat. 3. It is a glass tube closed at one end and is used in testing chemicals. For numbers 4–5, refer to the choices below: a. black magic b. alchemy c. traditional chemistry d. modern chemistry 4. During this period, people believed that lead can be transmuted into gold. 5. During this period, people believed in the four elements: fire, earth, water, and air. 6. Which of the following is not a qualitative observation? a. The red rose is wilting slowly. b. The stem of the rose has many thorns. c. The stem of the rose is 25 centimeters long. d. The rose has a sweet scent that fills the room. 7. Which of the following is not an integration of chemistry and information technology? a. Database for all chemicals found in the world b. Increased sales among all kinds of consumers c. Higher resistance of computers to heat and force d. Cheaper raw materials that can be used for making microchips 8. Which of the following is not correct? a. biochemistry: living organism b. inorganic chemistry: carbon containing compounds c. physical chemistry: properties of matter d. polymer chemistry: plastics 9. Which of the following is not a contribution of Antoine Laurent Lavoisier? a. disproof of the phlogiston theory b. metric system c. The Skeptical Chemist d. law of conservation of mass0 Discover Science: Chemistry

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