Chapter 9: First Law of Thermodynamics

Question 1

Define internal energy

Answer 1

The internal energy of a system is the sum of the random distribution of kinetic energy and potential energy of all the atoms or molecules

Question 2

Define heat

Answer 2

Heat is the energy exchanged between two bodies due to a temperature difference between them

Question 3

Define specific heat capacity

Answer 3

Specific heat capacity of a substance is thermal energy per unit mass to raise the temperature of a substance by one degree Kelvin

Question 4

Define specific latent heat of fusion

Answer 4

The specific latent heat of fusion is defined as the amount of thermal energy required per unit mass to change a substance from the solid phase to the liquid phase at constant temperature

Question 5

Define specific latent heat of vaporisation

Answer 5

The specific latent heat of vaporisation is defined as the amount of thermal energy required per unit mass to change a substance from the liquid phase to the vapour phase at constant temperature

Question 6

State the First Law of Thermodynamics

Answer 6

The First Law of Thermodynamics states that the increase in internal energy is equal to the sum of heat supplied to the system and the work done on the system.