Temperature & Ideal Gases And Thermodynamics

Question 1

Thermodynamic scale

Answer 1

The thermodynamic temperature scale is theoretical and is independent of the property of any real substance.

Question 2

Thermal equilibrium

Answer 2

Two bodies in thermal contact are said to be in thermal equilibrium when there is no net flow of heat from one body to another. It also implies that the two bodies are at the same temperature.

Question 3

Absolute zero

Answer 3

absolute zero (0 K) which is the temperature whereby the pressure of an ideal gas becomes zero.

Question 4

Triple point of water

Answer 4

triple point of water (273.16 K) which is the temperature whereby the three phases of water coexist in dynamic equilibrium

Question 5

One kelvin

Answer 5

One kelvin is defined to be 1/273.16 of the thermodynamic temperature of the triple point of water.

Question 6

Ideal gas

Answer 6

An ideal gas is one which obeys the equation pV = nRT, at all pressures, volumes and temperatures.

Question 7

Assumptions of kinetic theory for ideal gas

Answer 7

1. A gas consists of a very large number of molecules
2. The gas molecules are in constant random motion and obey the laws of mechanics
3. The molecules of gas make perfectly elastic collisions with one another and with the walls of the container
4. The intermolecular forces are negligible except during the time of collision which is very brief compared to the the time between collisions

Question 8

Heat capacity

Answer 8

Heat capacity of a body is defined as the quantity of heat absorbed or liberated by the body per unit temperature change.

Question 9

Specific heat capacity

Answer 9

Specific heat capacity of a material is defined as the quantity of heat absorbed or liberated per unit mass of the material per unit temperature change.

Question 10

Latent heat

Answer 10

Latent heat is defined as the quantity of heat absorbed or liberated by a substance in order to change the substance from one phase to another phase without a temperature change.

Question 11

Specific latent heat of fusion

Answer 11

Specific latent heat of fusion of a substance is defined as the quantity of heat required per unit mass to change the substance from the solid phase to the liquid phase without a change in temperature.

Question 12

Specific latent heat of vaporisation

Answer 12

Specific latent heat of vaporisation of a substance is defined as the quantity of heat required per unit mass to change the substance from the liquid phase to the vapour phase without a change in temperature.

Question 13

Temperature

Answer 13

The temperature T of a gas is a measure of the mean kinetic energy of particles in the gas.

Question 14

First law of thermodynamics

Answer 14

The first law of thermodynamics states that the increase in the internal energy of a system is equal to the sum of the heat supplied to the system and the work done on the system.

Question 15

Internal energy

Answer 15

The internal energy of a body is the sum of the random distribution of all the potential and kinetic energies of the molecules in the gas