Morning students. Today

we will learn about the

'Effect of Change of Temp. and

Pressure on States of Matter.'

Students, you know that states of

matter can be changed by

changing Temp. and Pressure.

Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot. Quantitatively, temperature is measured with thermometers, which may be calibrated to a variety of temperature scales.

The common used uits of temp. are the followig:

Celcius

Kelvin

fahrenheit

Effect of Change of Temp. on Solids

On incresing the temp. of solids, the kinetic energy of particles increses.Due to the increse in kinetic energy, the particles start vibrating with greater speed.the energy supplied by heat overcomes the forces of attraction between the particles. The particles leave their fixed position and start moving more freely. A stage is reached when the solid melts and is converted to a liquid.

Effect of Change of Temp. on Liquids

When we supply heat energy to water, particles start moving even faster. At a certain temperature a point is reached when the particles have enough energy to break free from the forces of attraction of each other. At this temp. the liquid starts changing into gas and finally gets converted int gas.

Effect of Change of Temp. On Gases

When we supply heat energy to gases the kinetic energy of particles increases and the particle motion increases and the particles move with a greater speed.

Pressure is an effect which occurs when a force is applied on a surface. Pressure is the amount of force acting on a unit area. The symbol of pressure is P.

Effect of Change of Pressure on Gases

On increasing the pressure on gases, the particles come closer to eachother.

Effect of Change of Pressure on Liquids

Effect of Change of Pressure on Solids

• Melting point-The temp. at which a solid

melts to become a liquid at the

atmospheric pressure is called meltiong

point.

Boiling point-The temp. at which a liquid

starts boiling at the atmospheric pressure

is called boiling point.

• Latent heat of fusion-The amount of heat required to convert one kg of a solid into liquid at atmospheric pressure at its melting point is called latent heat of fusion.

Latent heat of vaporisation-The amount of heat required to convert one kg of liquid into gas at atmospheric pressure at its boiling point is called latent heat of vaporisation.

Boiling is a bulk phenomenon.

Tke melting point of a solid is an indication of the strength of the force of attraction between its particles.

The melting point of ice=0 degree celcius/273 kelvin/32 degree fahrenheit.

The boiling point of water=100 degree celcius/373 kelvin/212degree fahrenheit.

Students,now I hope that you have

Understood the effect of change of temp.

and pressure on states of matter