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8.Nature-of-Matter-Elements-Compounds-and-Mixtures 8th-science-curiosity.pdf/by k sandeep swamy (M.Sc,B.Ed)

Nature of Matter: Elements, Compounds, and Mixtures/8th science curiosity By : K Sandeep Swamy(M.Sc,B.Ed) For Online Classes (IITJEE & NEET foundation and academics) contact : 9491878325 Subscribe Samyans Eduhub youtube channel Have you ever wondered what the world around you is made of? Everything we see and touch is composed of matter - from the air we breathe to the water we drink. In this presentation, we'll explore the fascinating world of matter and discover how elements, compounds, and mixtures form the building blocks of our universe. What is Matter? Definition Matter is anything that has mass and takes up space. It makes up the physical world around us - from the staircase you use to the air you breathe. Composition All matter is made up of tiny particles. Most things around us are not made of just one substance, but rather two or more substances mixed together. Non-Matter Not everything is matter. Light, heat, electricity, thoughts, and emotions are important parts of our world but are not made of matter. What Are Mixtures? When two or more substances are mixed, where each substance retains its properties, it is called a mixture. The individual substances that make up a mixture are called its components. The components of a mixture do not react chemically with each other. They can often be separated by physical methods. Examples of mixtures include: Poha (flattened rice with vegetables) Sprout salad Sugar dissolved in water Soups and lemonade Fig: Sprout salad - an example of a mixture Types of Mixtures In Non-Uniform Mixtures, the components are visibly distinct and unevenly distributed. You can often see the different parts with your naked eye or a magnifying device. Sprout salad (visible green gram, chickpeas, onion, and tomato) Sand and water Soil Conversely, Uniform Mixtures have components that are evenly distributed throughout, making them indistinguishable even under a microscope. They appear as a single phase. Sugar dissolved in water Salt dissolved in water Air Alloys: Special Uniform Mixtures Alloys are special uniform mixtures of metals or a metal and a non-metal. They are mixed so uniformly that the entire mixture appears the same throughout. Examples of alloys include: Stainless steel (iron, nickel, chromium, and carbon) Brass (copper and zinc) Bronze (copper and tin) In ancient India, alloys were called Mishraloha and were used for various purposes, including medicine. Fig: Utensils made of stainless steel, brass, and bronze Is Air a Mixture? Nitrogen Makes up about 78% of air Does not take part in combustion Oxygen Required by most living beings Helps in combustion Water Vapor Forms tiny droplets when warm air touches a cool surface Carbon Dioxide Present in small amounts Can be detected using lime water Air is a uniform mixture of gases. It also contains dust particles, which are considered pollutants and not an integral part of air. Testing for Carbon Dioxide in Air

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8.Nature of Matter: Elements, Compounds, and Mixtures/8th science curiosity By : K Sandeep Swamy(M.Sc,B.Ed) For Online Classes (IITJEE & NEET foundation and academics) contact : 9491878325 Subscribe Samyans Eduhub youtube channel Have you ever wondered what the world around you is made of? Everything we see and touch is composed of matter - from the air we breathe to the water we drink. In this presentation, we'll explore the fascinating world of matter and discover how elements, compounds, and mixtures form the building blocks of our universe.
What is Matter? Definition Matter is anything that has mass and takes up space. It makes up the physical world around us - from the staircase you use to the air you breathe. Composition All matter is made up of tiny particles. Most things around us are not made of just one substance, but rather two or more substances mixed together. Non-Matter Not everything is matter. Light, heat, electricity, thoughts, and emotions are important parts of our world but are not made of matter.
What Are Mixtures? When two or more substances are mixed, where each substance retains its properties, it is called a mixture. The individual substances that make up a mixture are called its components. The components of a mixture do not react chemically with each other. They can often be separated by physical methods. Examples of mixtures include: Poha (flattened rice with vegetables) Sprout salad Sugar dissolved in water Soups and lemonade Fig: Sprout salad - an example of a mixture
Types of Mixtures In Non-Uniform Mixtures, the components are visibly distinct and unevenly distributed. You can often see the different parts with your naked eye or a magnifying device. Sprout salad (visible green gram, chickpeas, onion, and tomato) Sand and water Soil Conversely, Uniform Mixtures have components that are evenly distributed throughout, making them indistinguishable even under a microscope. They appear as a single phase. Sugar dissolved in water Salt dissolved in water Air
Alloys: Special Uniform Mixtures Alloys are special uniform mixtures of metals or a metal and a non- metal. They are mixed so uniformly that the entire mixture appears the same throughout. Examples of alloys include: Stainless steel (iron, nickel, chromium, and carbon) Brass (copper and zinc) Bronze (copper and tin) In ancient India, alloys were called Mishraloha and were used for various purposes, including medicine. Fig: Utensils made of stainless steel, brass, and bronze
Is Air a Mixture? Air is a uniform mixture of gases. It also contains dust particles, which are considered pollutants and not an integral part of air. Nitrogen Makes up about 78% of air Does not take part in combustion Oxygen Required by most living beings Helps in combustion Water Vapor Forms tiny droplets when warm air touches a cool surface Carbon Dioxide Present in small amounts Can be detected using lime water
Testing for Carbon Dioxide in Air Activity: Using Lime Water Make lime water by adding calcium oxide to water 1. Filter the solution to get clear lime water 2. Leave the solution exposed to air 3. Observe that it turns milky over time 4. When carbon dioxide from the air reacts with calcium hydroxide (lime water), it forms calcium carbonate, which appears as tiny white particles, making the solution look milky. Calcium hydroxide + Carbon dioxide ³Calcium carbonate + Water Fig: Lime water turns milky in the presence of carbon dioxide
Types of Mixtures Based on Physical States Mixture Type Examples Uniform or Non-uniform Gas and gas Air Uniform Gas and liquid Aerated water (soda water), Oxygen dissolved in water Uniform Solid and gas Carbon particles in air Non-uniform Liquid and liquid Vinegar (acetic acid in water), Oil and water Uniform, Non-uniform Solid and liquid Sand and water, Seawater Non-uniform, Uniform Solid and solid Baking powder, Alloys Uniform Mixtures can be classified based on the physical states of their components. The uniformity of a mixture depends on how evenly the components are distributed.
What Are Pure Substances? In science, a pure substance is one that has no other substance present in it. It cannot be separated into other kinds of matter by any physical process. A pure substance consists of the same type of particles. All the constituent particles of that substance behave identically. Pure substances can be either: Elements Compounds This scientific definition differs from common usage, where "pure" often means unadulterated products. Fig: Products labeled as "pure" in everyday life Even products labeled as "pure" in everyday life may be considered impure in scientific terms if they contain more than one substance.
Exploring the Composition of Water Activity: Passing Electricity Through Water Fill a beaker with water and add a few drops of dilute sulfuric acid 1. Place a 9V battery inside the beaker 2. Place water-filled test tubes over each battery terminal 3. Observe gas bubbles forming in both test tubes 4. Test the gases with a burning candle 5. Results: One gas produces a "pop" sound (hydrogen) The other makes the flame glow brighter (oxygen) Fig: Passing electricity through water This experiment shows that water can be broken down into hydrogen and oxygen, which are elements. The chemical equation is: Water ³Hydrogen + Oxygen
What Are Elements? 1 Definition Elements are substances that cannot be broken down into simpler substances by chemical means. They are the building blocks of all matter. 2 Composition Each element is made up of identical particles called atoms. These particles are different from the particles of any other element. 3 Examples Hydrogen, oxygen, gold, silver, sulfur, carbon, iron, aluminum, etc. 4 Classification Elements can be classified as metals (gold, silver), non-metals (carbon, sulfur), or metalloids (silicon, boron). There are 118 known elements, most of which exist in a solid state. Eleven elements exist as gases at room temperature, and only two (mercury and bromine) are liquid.
Molecules of Elements The atoms of most elements cannot exist independently. Two or more atoms combine to form a stable particle called a molecule. For example: Two atoms of hydrogen (H) combine to form one molecule of hydrogen (H¢) Two atoms of oxygen (O) combine to form one molecule of oxygen (O¢) Some elements, like noble gases (helium, neon), exist as single atoms and don't form molecules. Fig: Molecular models of hydrogen (H¢) and oxygen (O¢)
What Are Compounds? Different Elements Two or more different elements combine Fixed Ratio Elements combine in a fixed ratio by mass New Substance A new substance forms with properties different from its constituent elements Chemical Bond Cannot be separated by physical methods Examples of compounds include water (H¢O), sodium chloride (NaCl), and sugar (C¡¢H¢¢O¡¡).
Water: A Compound Properties of Water vs. Its Elements Water is a liquid at room temperature, while hydrogen and oxygen are gases Water extinguishes fire, while oxygen supports combustion and hydrogen is highly flammable Water molecules contain hydrogen and oxygen atoms in a fixed 2:1 ratio The properties of water are completely different from those of hydrogen and oxygen Fig: Depiction of molecules of water Water molecules (H¢O) consist of two hydrogen atoms bonded to one oxygen atom. This fixed ratio is what makes water a compound rather than a mixture.
Exploring Sugar: A Compound Activity: Heating Sugar Put a teaspoon of sugar in a boiling tube 1. Heat it gently 2. Observe the changes 3. Observations: Sugar turns brown It begins to char (turns blackish) Water droplets form inside the tube Carbon (charcoal) is left behind Fig: Color of sugar changes on heating This experiment shows that sugar decomposes on heating to give carbon and water. Since water consists of hydrogen and oxygen, sugar is a compound containing carbon, hydrogen, and oxygen.
Iron and Sulfur: Mixture vs. Compound 1 Sample A: Mixture Iron filings and sulfur powder mixed together Yellow and black particles visible Iron can be separated using a magnet Iron reacts with acid to produce hydrogen gas Components retain their individual properties 2 Sample B: Compound Iron sulfide formed by heating iron and sulfur Uniform black mass Not attracted to a magnet Reacts with acid to produce hydrogen sulfide gas (rotten egg smell) Has properties different from iron and sulfur
Comparing Elements, Compounds, and Mixtures Property Elements Compounds Mixtures Composition One type of atom Two or more elements in fixed ratio Two or more substances in any ratio Properties Unique to each element Different from constituent elements Retain properties of components Separation Cannot be separated into simpler substances Can be separated by chemical methods Can be separated by physical methods Examples Hydrogen, oxygen, gold Water, salt, sugar Air, soil, seawater Understanding the differences between elements, compounds, and mixtures helps us better understand the nature of matter around us.
Applications of Elements, Compounds, and Mixtures Medicine Chemists study how elements combine to create compounds, enabling them to invent life-saving medicines and vaccines to fight diseases. Agriculture Knowledge of compounds helps in creating fertilizers that enhance crop production to feed the growing global population. Construction Engineers use mixtures like concrete, wood, and steel as building materials for structures like bridges and buildings. Technology More than 45 different elements are used in manufacturing a mobile phone, including its screen, battery, and other components.
Innovative Materials: Graphene Aerogel Material scientists have developed innovative materials by understanding elements, compounds, and mixtures. One example is graphene aerogel, considered the lightest material on Earth. Properties: Made from carbon (an element) Extremely lightweight - even grass can hold it Highly porous with high absorbing capacity Potential Applications: Environmental cleaner (e.g., oil spill cleanup) Energy-saving devices Special coatings for buildings Fig: Graphene aerogel - so light that flower can hold it
What Are Minerals? Most rocks are a mixture of minerals, which can be viewed with the eyes or using a magnifying glass or microscope. Types of Minerals: Native minerals: Pure elements like gold, silver, copper, sulfur, carbon Compound minerals: Made up of more than one element, like quartz, calcite, mica, pyroxene, and olivine Everyday Uses: Cement is made from calcite, quartz, alumina, and iron oxide Talcum powder is made from the mineral talc Fig: Various minerals
Traditional Art Using Elements and Compounds Dhokra Art An ancient craft from Bihar and Odisha that uses different metals to create beautiful figures inspired by nature. Process: Shape a design in beeswax 1. Cover the wax model with clay to make a mold 2. Melt out the wax after the clay hardens 3. Fill the hollow space with molten brass or bronze 4. The use of alloys (mixtures of metals) gives Dhokra art its strength and distinctive golden color. Fig: Dhokra art figures
Classifying Substances Elements Compounds Mixtures Elements Aluminum, gold, oxygen, sulfur, hydrogen, nitrogen Compounds Carbon dioxide, magnesium oxide, iron sulfide, glucose, water, sodium chloride, baking soda Mixtures Sand, seawater, muddy water, rust, air, fruit juice All elements and compounds are pure substances, while mixtures are not pure substances.
Testing for Carbon Dioxide in Air Carbon dioxide is a component of air that can be detected using lime water. When carbon dioxide reacts with lime water (calcium hydroxide solution), it forms calcium carbonate, which appears as a white precipitate, making the solution look milky. The chemical reaction is: Calcium hydroxide + Carbon dioxide ³Calcium carbonate + Water This reaction demonstrates the presence of carbon dioxide in air and is a simple way to test for this gas. The initially clear lime water solution turns milky when exposed to air containing carbon dioxide.
Practical Applications and Future Innovations 118 Known Elements Building blocks that form all matter in our universe 10M+ Known Compounds Created through chemical combinations of elements 45+ Elements in a Phone Different elements used in manufacturing a mobile phone Understanding elements, compounds, and mixtures has led to countless innovations in medicine, technology, construction, and environmental science. Future discoveries could lead to new materials with extraordinary properties, more effective medicines, and solutions to environmental challenges like carbon dioxide absorption.
Key Takeaways 1 Matter Classification Matter can be classified as mixtures (uniform or non-uniform) or pure substances (elements or compounds). 2 Elements Elements are the simplest substances that cannot be broken down further. They are the building blocks of all matter. 3 Compounds Compounds are formed when different elements combine chemically in fixed ratios. They have properties different from their constituent elements. 4 Mixtures Mixtures consist of two or more substances mixed together, where each substance retains its individual properties. 5 Practical Importance Understanding elements, compounds, and mixtures is essential for innovation in medicine, technology, construction, and environmental science.