Particle Model of Matter Vocab

Internal Energy

The sum of the kinetic and potential energies of all the particles in a system

Specific Latent Heat of Vaporisation

The energy required to change the state of 1 kg of a  substance from liquid to gas at a constant temperature. It is released during condensation and taken in during boiling;

Specific Heat Capacity

The energy required to increase the temperature 1kg of  a substance by 1^oC

Specific Latent Heat of Fusion

The energy required to change the state of 1 kg of a substance from solid to liquid at a constant temperature. It is released during freezing and taken in when melting

Model Answer 

Pressure in a gas

Gas particles collide with the walls of the container. Each collision exerts a force. The force is at right angles to the surface. The pressure is the total force applied over the area of the container in a given time. P=F/A.

Model Answer: Pressure in a gas, increasing  the temperature

Increasing the temperature increases the speed of gas molecules. There are more frequent collisions with the walls of the container. Each collision exerts a larger force. The  total force across the area of the container in a given time increases. So the pressure increases

Model Answer: Pressure in a gas,  decreasing the volume TEMPERATURE CONSTANT

There are more frequent collisions with the walls of the container. The total force across the area of the container in a  given time increases. So the pressure increases.

Boyle's Law

Pressure and volume in a gas are inversely proportional at a constant temperature

Model Answer: Work done on a gas TEMPERATURE CHANGES

Work is done on the gas when decreasing its volume. This increases the internal energy of a gas. And so the temperature increases (the opposite is true if the volume increases).