Physics: Gas Laws, Internal Energy, and Latent Heat Concepts

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 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.

Specific Heat Capacity

The energy required to increase the temperature of 1 kg of a substance by 1°C.

Pressure in a gas

Gas particles collide with the walls of the container. Each collision exerts a force that 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.

Increasing Temperature Effect on Gas Pressure

Increasing the temperature increases the speed of gas molecules, leading to more frequent collisions with the walls of the container. Each collision exerts a larger force, increasing the total force across the area of the container in a given time, thus increasing the pressure.

Decreasing Volume Effect on Gas Pressure

When the volume decreases (temperature constant), there are more frequent collisions with the walls of the container, increasing the total force across the area of the container in a given time, thus increasing the pressure.

Boyle's Law

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

Work done on a gas

Work is done on the gas when decreasing its volume, which increases the internal energy of a gas and thus increases the temperature.