This document provides an introduction to chemistry. It defines chemistry as the study of matter and its transformations. Matter is anything that has mass and takes up space. Chemistry is important because it is all around us in things like air, food, clothes, and textbooks. The document distinguishes between science and technology, with science pursuing knowledge and technology applying scientific knowledge for practical purposes. It outlines the scientific method and provides examples of its application. It also describes the classification of matter into elements, compounds, and mixtures and provides examples of each. Finally, it discusses the three states of matter - solid, liquid, and gas - and changes between these states like melting, boiling, condensation, and deposition.

1. CHAPTER 1CHAPTER 1
WHAT IS CHEMISTRY?WHAT IS CHEMISTRY?

2. WHAT IS CHEMISTRY?WHAT IS CHEMISTRY?
 Chemistry is the study of matter and theChemistry is the study of matter and the
transformations it undergoes.transformations it undergoes.
 What is matter?What is matter?
– Anything that has mass and takes up space.Anything that has mass and takes up space.

3. IMPORTANCE OF CHEMISTRYIMPORTANCE OF CHEMISTRY
 Chemistry is all around you.Chemistry is all around you.
– Air you breatheAir you breathe
– Food you digestFood you digest
– Clothes you wearClothes you wear
– Textbook you readTextbook you read
 Chemistry is often said to be the centralChemistry is often said to be the central
science.science.

4. SCIENCE V.S. TECHNOLOGYSCIENCE V.S. TECHNOLOGY
 How is science different from technology?How is science different from technology?
 Science:Science:
– Experimental investigation and exploration of naturalExperimental investigation and exploration of natural
phenomenaphenomena
– Pursues knowledge for its own sakePursues knowledge for its own sake
– Does not cause change in itselfDoes not cause change in itself
 TechnologyTechnology
– The practical application of scientific knowledgeThe practical application of scientific knowledge
– Leads to change (for better or for worse)Leads to change (for better or for worse)

5. SCIENCE V.S. TECHNOLOGY (Cont)SCIENCE V.S. TECHNOLOGY (Cont)
 Examples of science:Examples of science:
– What causes the flu?What causes the flu?
– How are atoms put together?How are atoms put together?
– How is genetic information stored and transmitted?How is genetic information stored and transmitted?
 Examples of technologyExamples of technology
– Flu vaccineFlu vaccine
– Atomic bombAtomic bomb
– Genetic engineeringGenetic engineering

6. SCIENTIFIC METHODSCIENTIFIC METHOD
 Step 1: Make observationsStep 1: Make observations
– Example: I am sick with a stomachache.Example: I am sick with a stomachache.
 Step 2: Develop a hypothesisStep 2: Develop a hypothesis
– Example: I am sick due to the spoiled food I ateExample: I am sick due to the spoiled food I ate
for lunch.for lunch.
 Step 3: Test hypothesis throughStep 3: Test hypothesis through
experimentsexperiments
– Example: Ask others who ate the same food for lunchExample: Ask others who ate the same food for lunch
if they got sick.if they got sick.

7. SCIENTIFIC METHOD (Cont)SCIENTIFIC METHOD (Cont)
 Step 4: Develop a lawStep 4: Develop a law
– Law:Law: Summarizes the outcome of severalSummarizes the outcome of several
experiments that occur repeatedly and consistently.experiments that occur repeatedly and consistently.
– Example: The spoiled food served at lunch makesExample: The spoiled food served at lunch makes
people sick with a stomachache.people sick with a stomachache.
 Step 5: Develop a theoryStep 5: Develop a theory
– Theory:Theory: Explanation for a why a law exists.Explanation for a why a law exists.
– Example: It is the bacteria in the spoiled food thatExample: It is the bacteria in the spoiled food that
makes people ill.makes people ill.

8. SCIENTIFIC METHOD (Cont)SCIENTIFIC METHOD (Cont)
 TheoriesTheories
– Are never completely certainAre never completely certain
– May change as more experiments areMay change as more experiments are
performed.performed.
– AA modelmodel is a physical picture or mathematicalis a physical picture or mathematical
expression of a theory.expression of a theory.
 Example: Model of the atomExample: Model of the atom
 The scientific method must be free of bias.The scientific method must be free of bias.

9. CLASSIFICATION OF MATTERCLASSIFICATION OF MATTER

10. ELEMENTSELEMENTS
 Elemental substances contain only oneElemental substances contain only one
type of atomtype of atom
 Elements are the building blocks ofElements are the building blocks of
mattermatter
 There are 115 known elements today, 90There are 115 known elements today, 90
which occur naturallywhich occur naturally
 The periodic table displays the elementsThe periodic table displays the elements

11. ELEMENTS (Cont)ELEMENTS (Cont)
 Each element has a unique symbolEach element has a unique symbol
– The first letter is always capitalized, theThe first letter is always capitalized, the
second letter is always lower casesecond letter is always lower case
 Fluorine is F, not fFluorine is F, not f
 Cobalt is Co, not CO (which is carbon monoxide)Cobalt is Co, not CO (which is carbon monoxide)
 The smallest unit of an element is theThe smallest unit of an element is the
atomatom

12. COMPOUNDSCOMPOUNDS
 Pure substances containing more than onePure substances containing more than one
different element.different element.
– NaCl (table salt)NaCl (table salt)
 Contains sodium (Na) and chlorine (Cl)Contains sodium (Na) and chlorine (Cl)
 NaCl is theNaCl is the chemical formulachemical formula
– HH22O (water)O (water)
 Contains 2 atoms of hydrogen (H) and 1 atom of oxygen (O)Contains 2 atoms of hydrogen (H) and 1 atom of oxygen (O)
 HH22O is the chemical formulaO is the chemical formula
 Elements in compounds are combined in aElements in compounds are combined in a
definite ratiodefinite ratio
– HH22O is water but HO is water but H22OO22 is hydrogen peroxideis hydrogen peroxide

13. COMPOUNDS (cont)COMPOUNDS (cont)
 Are HAre H22 and Oand O33 considered elements orconsidered elements or
compounds? Why?compounds? Why?

14. CLASSIFICATION OF MATTERCLASSIFICATION OF MATTER
Classify the following as an element,Classify the following as an element,
compound, homogeneous mixture, orcompound, homogeneous mixture, or
heterogeneous mixture.heterogeneous mixture.
a.a. FogFog
b.b. GasolineGasoline
c.c. HeliumHelium
d.d. Sulfuric acid (HSulfuric acid (H22SOSO44))
e.e. Orange juice from squeezed orangesOrange juice from squeezed oranges

15. STATES OF MATTERSTATES OF MATTER
SolidSolid LiquidLiquid GasGas
Copyright © 2005 by Pearson Education, Inc.
Publishing as Benjamin Cummings

16. WATER AND ITS STATES OF MATTERWATER AND ITS STATES OF MATTER

17. CHANGES IN STATECHANGES IN STATE
 Melting: Solid to liquidMelting: Solid to liquid
 Boiling: Liquid to gasBoiling: Liquid to gas
 Sublimation: Solid to gasSublimation: Solid to gas
– The above three require input of energyThe above three require input of energy
 Condensation: Gas to liquidCondensation: Gas to liquid
 Freezing: Liquid to solidFreezing: Liquid to solid
 Deposition: Gas to solidDeposition: Gas to solid
– The above three release energyThe above three release energy

18. PHYSICAL CHANGESPHYSICAL CHANGES
 Do not alter the chemical identity of theDo not alter the chemical identity of the
substancesubstance
– Examples include:Examples include:
 Any change in the state of matter (e.g. freezing orAny change in the state of matter (e.g. freezing or
boiling water)boiling water)
 Sawing woodSawing wood
 Crushing a tabletCrushing a tablet
 Bending a wireBending a wire
 Dissolving salt in waterDissolving salt in water

19. PHYSICAL PROPERTIESPHYSICAL PROPERTIES
 Characterize the physical state andCharacterize the physical state and
physical behavior of a substancephysical behavior of a substance
 Each substance has unique physicalEach substance has unique physical
propertiesproperties
 ExamplesExamples
– Sulfur appears as a yellow powderSulfur appears as a yellow powder
– The boiling point of water is 100The boiling point of water is 100 oo
CC
– Carbon monoxide is odorlessCarbon monoxide is odorless

20. CHEMICAL CHANGESCHEMICAL CHANGES
 Changes the identity of the substance asChanges the identity of the substance as
the chemical composition changes.the chemical composition changes.
– Also calledAlso called chemical reactionschemical reactions
 Examples:Examples:
– Tarnishing of silverTarnishing of silver
(Ag forms AgS)(Ag forms AgS)
– Rusting of ironRusting of iron
(Fe forms Fe(Fe forms Fe22OO33))

21. CHEMICAL REACTIONSCHEMICAL REACTIONS
 Are expressed using chemical equations.Are expressed using chemical equations.
 Rusting of iron:Rusting of iron:
4 Fe + 3 O4 Fe + 3 O22  2 Fe2 Fe22OO33 (rust)(rust)
reactants productsreactants products
Meaning:Meaning:
Four atoms of iron react with threeFour atoms of iron react with three
molecules of oxygen to form twomolecules of oxygen to form two
molecules of rustmolecules of rust

22. CHEMICAL REACTIONS (Cont)CHEMICAL REACTIONS (Cont)
Zn + 2 HClZn + 2 HCl  ZnClZnCl22 + H+ H22
Zinc hydrochloric acid zinc chloride hydrogen gasZinc hydrochloric acid zinc chloride hydrogen gas
Meaning:Meaning:
One atom of zinc reacts with twoOne atom of zinc reacts with two
molecules of hydrochloric acid to producemolecules of hydrochloric acid to produce
one molecule of zinc chloride and oneone molecule of zinc chloride and one
molecule of hydrogen gas.molecule of hydrogen gas.

23. CHEMICAL PROPERTIESCHEMICAL PROPERTIES
 Describe ways pure substances behaveDescribe ways pure substances behave
when interacting with other purewhen interacting with other pure
substances.substances.
 ExamplesExamples
– Iron reacts with oxygen to form rust.Iron reacts with oxygen to form rust.
– Platinum does not react with oxygen at roomPlatinum does not react with oxygen at room
temperature.temperature.

24. PRACTICE PROBLEMPRACTICE PROBLEM
Identify the following properties andIdentify the following properties and
changes as physical or chemical.changes as physical or chemical.
a.a. The copper sheets that form the “skin” ofThe copper sheets that form the “skin” of
the Statue of Liberty have acquired athe Statue of Liberty have acquired a
greenish coating over the years.greenish coating over the years.
b.b. Carbon appears as black powder.Carbon appears as black powder.
c.c. Adding food coloring to water.Adding food coloring to water.
d.d. Wood burns in air.Wood burns in air.