Thermal Energy

Question 1

Pressure

Answer 1

Force per unit Area.

Question 2

Internal Energy

Answer 2

The sum of the random distribution of kinetic and potential energies associated with the molecules of a system.

Question 3

Change of State

Answer 3

A change of state of a substance leads to a change in its Internal Energy but not its temperature.

Question 4

Specific Heat Capacity

Answer 4

The quantity of thermal energy required to raise the temperature of a unit mass of the substance by a unit temperature rise.

Typically measured in Joules per kg per Kelvin (J kg-1 K-1).

Question 5

Specific Latent Heat of Fusion

Answer 5

Quantity of energy per unit mass to change it at a constant temperature from a solid into a liquid.

Question 6

Absolute Zero

Answer 6

The temperature at which a substance has minimum internal energy.

Question 7

Boyles law

Answer 7

For a constant mass of gas at a constant temperature, the pressure exerted by the gas is inversely proportional to the volume it occupies.

P = constant/V

Question 8

Charles’s law

Answer 8

For a constant mass of gas at a constant pressure, the volume occupied by the gas is proportional to its absolute temperature.

V = constant x T

Question 9

Pressure law

Answer 9

For a constant mass of gas at a constant volume, the pressure exerted by the gas is proportional to its absolute temperature.

P = constant x T

Question 10

Kinetic Theory of Gases Assumptions

Answer 10

1. A gas contains a very large number of spherical particles (atoms or molecules).
2. The forces between particles are negligible, except during collisions.
3. The volume of the particles is negligible compared to the volume occupied by the gas.
4. Most of the time a particle moves in a straight line at a constant velocity.
5. The time of collision with each other, or the walls of the container is negligible compared with the time between collisions.
6. The collisions of the particles with each other and with the container are perfectly elastic, so that no kinetic energy is lost.

Also, the mean translational KE of a particle of an ideal gas is proportional to the thermodynamic temperature.