3. Thermal physics

Question 1

Temperature

Answer 1

a measure of the average random kinetic energy of the particles in a substance.

Question 2

Specific latent heat of fusion/vaporisation

Answer 2

the energy required to change the phase of 1kg of a substance from a solid/liquid to a liquid/gas without any temperature change.

Question 3

The specific heat capacity of a substance

Answer 3

the energy required to heat 1kg of a substance by 1K.

Question 4

Internal energy

Answer 4

the total of the potential energy and the random kinetic energy of all the particles in the substance.

Question 5

Absolute temperature

Answer 5

a temperature measured from absolute zero in kelvins.

Question 6

Pressure

Answer 6

the force per unit area.

Question 7

 Idea gas =

Answer 7

a hypothetical gas whose molecules occupy negligible space and have no interactions, and which consequently obeys the gas laws exactly.

Question 8

 Boyle’s law =

Answer 8

for a fixed mass of gas at constant temperature the pressure is inversely proportional to the volume.

Question 9

 Charles’ law =

Answer 9

for a fixed mass of gas at constant pressure the volume is directly proportional to the absolute temperature.

Question 10

 Pressure law =

Answer 10

for a gas of fixed mass and volume, the pressure is directly proportional to the absolute temperature.

Question 11

 Mole/avagadros constant =

Answer 11

the number of molecules in 12g of carbon 12.

Question 12

 Molar mass =

Answer 12

the mass of a substance divided by the number of molecules.

Question 13

 Thermal energy =

Answer 13

the net amount of energy transferred between two bodies at different temperatures.