Matter & its composition

Basically for ICSE / CBSE Board according to its School Curriculum.

1. Presented by NEHA AGARWAL

2. CHEMISTRY

3. According To The ICSE Curriculum… For Upper Primary Classes(VI-VIII)

4. MATTER & ITS COMPOSITION Learning Outcomes : Describe matter. Nature of matter. Discuss its Composition & properties. State of matter, inter-conversion of one state of matter into another. Effect of heat on matter(expansion, change of state & chemical change)

5. MATTER Anything which occupies space, has mass, volume and can be felt by the senses is called matter. Everything around us is made of matter. Many of things are used by us in our everyday life like we eat food , drink water , use table , chair , clothes , bed etc. also human beings , animals , plants, rocks & minerals, alcohols, gaseous substances are all examples of matter.

6. Everything shown here is Matter. Some of them are solids , some are liquids , some gaseous . All these things take up space, have weight. How much a thing weights depends on its mass.

7. NATURE OF MATTER Living Matter Non-living Matter It does not grow, move or reproduce on its own. Natural matter that occurs in nature. Man made matter produced artificially from natural matter. The earth is home of all kinds of plants & animals. They can grow, move and reproduce on their own.

8. Properties of Matter Basically two types of properties have seen in matter. PHYSICAL PROPERTIES. CHEMICAL PROPERTIES. Physical properties which include state , colour , odour , density etc. Chemical properties include reactions of different materials with different chemical. Physical properties of matter are : Colour - All matter can be distinguished by their varied colours . Odour - Matter shows variation in odour and smell. Solubility -Matter may vary solubility in water or other solvents. Melting and Boiling points - Subtances variation in their melting and boiling points.

9. Composition of Matter Everything around us is made of tiny particles, therefore all matters in our nature is built of extremely tiny particles called MOLECULES and these molecules are made of smallest particles called ATOMS . So ATOMS are the smallest particles from which matter is made up and MOLECULES are the smallest building block unit of matter. MATTER MOLECULES ATOMS

10. ATOMS And MOLECULES ATOMS MOLECULES Smallest particles of an element. Smallest particle of a compound. It may or may not exist independently. It always exist independently. Atoms form molecules. Molecules are composed of atoms. Example ; Hydrogen atom (H),Oxygen atom (O), Carbon atom (C) etc. Example; Hydrogen Molecule (H-H), Oxygen molecule (O=O). Atoms have no chemical bonding. Molecules have inter-molecular and intra-molecular forces due to chemical bonding. Atoms have no further kinds. Molecules are two types. Homo-atomic. Hetero-atomic. Except some of noble gas, other atoms are highly reactive. Molecules are less reactive.

11. MATTER (WATER) Molecule of water (Smallest building block unit) Atom (from which molecules of water made of) + 2

12. STATE OF MATTER The state of matter depend on the nature of the molecules present in it and how they are arranged . For example; different state of water which is a matter … Ice ,which is Water in a solid state (because here the molecules of water are packed close to each other ) can be changed into Liquid state ( molecules of water are not as tightly packed as in solids state)by heating it. On further heating The water ,when temperature reaches upto 100 degree celsius , changes into gaseous state ( molecules of water are very far apart ). So MATTER has three states: 1.SOLID STATE. 2. LIQUID STATE. 3. GASEOUS STATE. These three forms are inter convertible which means they can be converted from one state of matter into another and again back to the original state.

13. What causes a difference in States? Matter is made up of very tiny particles, called molecules. These molecules of matter have certain force of attraction between them. The force is known as Cohesion force or Inter-molecular force. For details at first we want to know what is… Inter-molecular force : The molecules of matter are always in motion and attract each other with a force which is known as Inter-molecular force of attraction due to which they are held together. Inter-molecular space : The space between the molecules is called inter-molecular space. When molecules of matter are very closely packed , cannot move away from one another, can only vibrate about fixed positions means inter-molecular force of attraction is strong there and also space between molecules is negligible then SOLID STATE OF MATTER is exist. Similarly when inter-molecular force of attraction between molecules of matter is weaker than in solids and the molecules are farther apart and not tightly held in their position means they can slip over one another then LIQUID STATE OF MATTER is exist. On the other part when molecules are very far apart and inter-molecular space is maximum and cohesion is much weaker than in liquid and solids then GASEOUS STATE OF MATTER is exist.

14. Properties of Gaseous State A gas has neither fixed volume nor a fixed shape. Gases can be compressed to a much larger extent than solids and liquids A gas expand or contracts to a great extent on being heated or cooled. A gas tends to move from a higher to a lower-pressure zone. Gas has very weak intermolecular force.

15. Interconversion of State of MATTER The three states of matter can be converted from one state to another and again back to the original state. For interconvertibily to take place there has to be change of conditions: HEAT (or process of heating). COOL (or process of cooling). Change of PRESSURE.

16. Action of Heat on MATTER When any kind of matter is heated, it gradually undergoes changes in the following steps : Expansion Change in state Chemical change Let us see how these changes occur; Change in State : If you heat or cool water up to a certain temperature, its state changes. In general a solid changes into liquid and a liquid into a gas on being heated enough. The opposite changes take place when a substance is cooled sufficiently.

17. Change In State during heating & cooling process

18. Changes in Solid to Liquid state The temperature at which a solid melts is called the Melting Point of the solid and the changes in state from solid to liquid is known as Melting. Actually when heated , the molecules in a solid gain some energy and vibrate more vigorously . When heated sufficiently, the molecules gain enough energy to overcome inter-molecular attraction and move far apart. Hence a solid changes into liquid. On further cooling , the molecules become even less energetic and move still closer, the inter-molecular force increases and the liquid becomes a solid . The temperature at which liquid becomes turn into its solid state is called Freezing point of the liquid . The changes in state from liquid to solid is called Freezing.

19. Changes in Liquid to Gaseous State The temperature at which a liquid boils is known as its Boiling point . The change in state from liquid to gaseous is known as Vaporization or Evaporation . Actually as a liquid is heated ,the molecules gain energy and move more vigorously, some of them gain enough energy to move far away from the other molecules , to form a gas. A liquid evaporates faster as the temperature is raised. When the temperature reaches a certain point, the liquid begins to boil. On cooling , the molecules of a gas lose energy And slow down. The inter-molecular space Decreases and cohesion increases. So the gas Changes into a liquid. The change in state from gaseous to liquid is called Condensation or Liquefaction .

20. Changes in Solid to Gaseous State Some solids vaporize without melting, when heated, solid melts into a liquid before changing into gas. However,  Sublimation  is a chemical process that skips the liquid phase, causing solid to directly turn to gas.  This typically occurs when the substance absorbs excess energy from its surrounding, skipping the liquid phase altogether. Real life examples; Naphthalene(the chemical substance in mothballs),Iodine , Dry ice, Ammonium Chloride are common substance that sublime.

21. Solid  carbon dioxide  ( dry ice ) sublimes everywhere . Naphthalene , an organic compound commonly found in pesticides such as  mothballs , sublimes easily because it is made of non-polar molecules that are held together only by  van der Waals intermolecular forces. Naphthalene is a solid that sublimes at  standard atmospheric temperature with the sublimation point at around 80 °C. Iodine  produces fumes on gentle heating.

22. CHEMICAL CHANGES On being heated, many substance undergo a chemical changes. Let us discuss the interesting examples: Burning of a Candle: Weigh a candle, light it and watch. You’ll observe the following things: The wax near the wick melts and a part of it flows down and solidifies( a change in state). 2. A part of the wax melt vaporizes (again a change in state). 3. The vapors catch fire and burn to form soot, carbon dioxide and water vapors … This is a Chemical Change.

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