-State the distinguishing properties of solids, liquids and gases

Solid has definite shape and volume. Liquid has indefinite shape but definite volume. Gas has indefinite shape and volume. 

Solid and liquid cannot be compressed but gas can be compressed. 

-Describe the structures of solids, liquids and gases in terms of particle separation, arrangement and motion

Particles In Different States 

-Describe changes of state in terms of melting, boiling, evaporating, freezing and condensing. 

-Explain changes of state in terms of kinetic particle theory, including the interpretation of heating and cooling curves

Heating curve

Substance is in solid state. As temperature increases, more thermal energy is converted to kinetic energy of the particles. Particles rotate and vibrate more at their fixed positions.

 

At melting point:Thermal energy is absorbed from surroundings, Particles with increased energy can overcome the very strong forces of attraction in the solid state. Both solid and liquid state are present.  Temperature remains constant. 

 

 All the substance has melted. substance is in liquid state. Particles are close to each other and move freely throughout the liquid. As temperature increases, more thermal energy is converted to kinetic energy of the particles. Particles slide past each other with increasing speed.. 

At boiling point: Thermal energy is absorbed from surroundings, Particles with increased energy can overcome the  strong forces of attraction in the liquid state. Particles move further apart, quickly and randomly. Both liquid and gaseous state are present.  Temperature remains constant

All the substance has boiled. substance is in gaseous state. Thermal energy is absorbed from surroundings, more thermal energy is converted to kinetic energy of the particles. Particles are far apart from each other and move freely in any directions at high speeds.

Cooling Curve

Substance is in gaseous state; temperature decreases and kinetic energy of the particles is converted to thermal energy. Particles move slower and closer with lesser kinetic energy. 

At condensation point: Kinetic energy  of the particles is converted to thermal energy.  Particles with lesser energy are drawn closer by strong forces of attraction. Both gaseous and liquid state are present. Temperature remains constant. 

Substance is in liquid state. As temperature decreases, more kinetic energy of the particles is converted to thermal energy. Particles move slower with lesser kinetic energy. 

At freezing point:  Kinetic energy  of the particles is converted to thermal energy.  Particles with lesser energy are drawn closer by strong forces of attraction. Particles become more orderly arranged. Both liquid and and solid state are present. Temperature remains constant. 

Substance is in solid state. As temperature decreases and kinetic energy of the particles is converted to thermal energy. Particles can vibrate and rotate about their fixed positions. 

-Describe the effects of temperature and pressure on the volume of a gas

As the temperature of gas increases, the particles have more kinetic energy and move more quickly and further apart.
Particles occupy more space and volume of the gas will increase. 

As the temperature falls, the particles move slower and closer. Particles take up less space and volume of the gas will decrease. 
 

• If pressure increases, particles are forced closer together and they occupy less space. Volume of gas decreases. 

• If pressure decreases, particles can move further apart and they occupy more space. Volume of gas increases. 

Supplement
Gas pressure is caused by the force exerted on walls of container when the gas particles collide against the walls of the container.  As the temperature of the gas increases, the particles gain more kinetic energy and they move more quickly and collide against the walls more and force exerted is more. Pressure increases.

When a gas is compressed into a smaller space, its pressure increases. If enough force is applied, the particles can be pushed so close that the gas turns into a liquid.