9: Thermodynamics

Question 1

Define total internal energy

Answer 1

The sum of the kinetic and potential energy of the molecules within a system

Question 2

Define specific heat capacity

Answer 2

The energy needed to raise the temperature of 1 kg of a substance by 1 K

Question 3

Define specific latent heat

Answer 3

The thermal energy required to change the state of 1 kg of a substance

Question 4

Explain, in terms of momentum, why pressure exerted by air decreases as temperature decreases.

Answer 4

Kinetic energy of molecules is less,
Collision rate with walls of container is smaller,
Rate of change of momentum is less,
Therefore a smaller force on the container walls.