Matter In Our Surroundings Introduction Matter is a substance which occupies space and has weight. Like the air we breath, the food we eat, stones, clouds, etc even a small drop of water or a particle of sand every this is matter. Matter is made up of particles, particles of matter have space between them and are continuously moving and attract each other. States of Matter There are three states of matter 1. Solid State :- It is a state of matter where particles are closed to each other. 2. Liquid State :- It is a state of matter where particles are apart from each other. 3. Gaseous State :- It is a state of matter where particles are very far from each other. Interconversion of States of Matter 1. Conversion of Solid to Liquid :- The process of conversion of solid to liquid state is known as "melting", and the point at which solid starts melting is called melting point. H2O ------> H2O 2. Conversion of Liquid to Gas :- The process of conversion of liquid to gaseous state is known as "boiling", and the point at which liquid starts boiling is called its boiling point. H2O ----> H2O
3. Conversion of Liquid to Solid State :- The process of conversion of liquid to solid is called "freezing" or "solidification". H2O -----> H2O Water ----> Ice 4. Conversion of Gas to Liquid State :- The process of conversion of gas to liquid state is known as "condensation". H2O -----> H2O 5. Conversion of Solid to Gas :- The process of conversion of solid to gas state without changing into liquid state is known as "Sublimation". H2O ----> H2O 6. Conversion of Gas to Solid State :- The process of conversion of gas to solid without changing into liquid state is known as "Desublimation". H2O ------> H2)
Comparison of Solid, Liquid and Gaseous State S. No. Parameters Solid Liquid Gas 1. Volume and shape Definite Shape and Volume. Shape of container and definite volume. No definite shape and volume. 2. Compressibility Cannot be compressed except porous solids. Cannot be compressed. Can be compressed easily. 3. Flow Particles do not flow. Particles flow. Particles flow easily. 4. Diffusion Diffuse slowly Diffuse fast Diffuse very fast. 5. Force of attraction High between particles Less Very less 6. Inter-molecular space Very less More Large 7. Kinetic Energy Less Medium highest What is Evaporation? Evaporation is a surface phenomenon. Particles from the surface gain enough energy to overcome the forces of attraction present in the liquid and change into the vapour state. The rate of evaporation depends upon the surface area exposed to the atmosphere, the temperature, the humidity and the wind speed. Evaporation causes cooling. Diffusion Movement of particles from their higher to lower concentration For eg. Spreading out the fragrance of incense stick(agarbatti) through the room. Compressibility/Compression Conversion of Gas to Liquid state by applying pressure and lowering temperature. For Eg. L.P.G(Liquid Petroleum Gas), C.N.G(Compressed Natural Gas) Interconversion of Temperature 10 C+273 = 283K 288K - 273 = 10 C
Latent Heat Heat energy that is used up by a body to change its state or phase is known as latent heat. Latent Heat of Fusion :- Amount of heat energy required to change 1Kg of a solid into liquid at its melting point. Latent Heat of Evaporation :- Amount of heat energy required to change 1L of liquid to gas at its boiling point. Difference between Boiling and Evaporation S.No. Boiling Evaporation 1. Bulk phenomenon takes place in Surface phenomenon takes place whole water taken in a pot. only at the surface. 2. Whole water changes to water Surface water changes to water vapour. vapour. 3. At boiling point. At any temperature below boiling point. 4. Boiling produce heat. Evaporation produce cooling. 5. Eg. Water -> Water Vapour Eg. -> Conversion of sea water - > water Vapour Some Measurable Quantities and their Units Quantity Unit Symbol Temperature Kelvin K Length Metre M Mass Kilogram Kg Weight Newton N Volume Cubic metre m 3 Density Kilogram per cubic metre Kg/m -3 Pressure Pascal Pa Important Diagrams in this chapter