Internal energy & Temperature

Question 1

The internal energy of an object is:

Answer 1

The sum of the random distribution of the kinetic and potential energy of its molecules.

Question 2

The thermal energy of the object:

Answer 2

• Is dependent on the kinetic energy of the molecules
• Which depends on the temperature of the object
• The hotter they are the faster the vibrate.

Question 3

The potential energy of the molecules:

Answer 3

• Depends how far away from each other they are
• Is greater in a liquid than in a solid.

Question 4

What is temperature?

Answer 4

A measure of the degree of hotness of an object.

Defined in terms of ‘fixed points’

Question 5

Celsius scale measured in °C has:

Answer 5

ice point at 0 °C and steam point at 100 °C at atmospheric pressure.

Question 6

What is the triple point of water?

Answer 6

The temperature at which ice, water and water vapour are in thermal equilbrium

273.16 K

Question 7

The first law of thermodynamics says:

Answer 7

Change in internal energy of object = total energy transfer due to work done and heating

Question 8

Energy transfer takes place between two objects if:

Answer 8

• One object does work on the other one
• One object is hotter than the other one.

Question 9

What is thermal equilibrium?

Answer 9

When no overall heat transfer occurs between two objects at the same temperature.

Question 10

What is absolute zero?

Answer 10

The lowest possible temperature, the temperature at which an object has minimum internal energy.

Question 11

Kelvin to celsius

Answer 11

K - 273.15

Question 12

Celsius to Kelvin

Answer 12

°C + 273.15