13. Kinetic theory of gases

Energy of all molecules of a monatomic gas having

a volume V and pressure P is 3/2 PV . The total kinetic energy of all molecules of a diatomic gas at the same

Volume and pressure is

• 3PV

The temperature of a gas is raised while its volume remains constant, the pressure exerted by a gas on the walls of the container increases because its molecules

• lose more kinetic energy to the wall.

• are in contact with the wall for a shorter time.

• strike the wall more often with higher velocities.

• collide with each other less frequency.

The average translational kinetic energy of O₂ (molar mass 32) molecules at a particular temperature is 0.048 eV. The translational kinetic energy of N₂ (molar mass 28) molecules (in eV) at the same temperature is

• 0.0015

• 0.003

• 0.048

• 0.768

The expansion of an ideal gas of mass m at a constant pressure P is given by the straight line D. Then the expansion of the same ideal gas of mass 2m at a pressure P/2 is given by the straight line

• E

• C

• B

• A

The expansion of unit mass of a perfect gas at constant pressure is shown in the following figure. Here,

• a = volume, b = °C temperature.

• a = volume, b = K temperature.

• a = °C temperature, b = volume

• a = K temperature, b = volume.

Find the ratio of specific heat capacity at constant pressure to the specific heat capacity at constant volume for NH₃.

• 1.33

• 1.44

• 1.28

• 1.67

A gas is heated at constant pressure. The fraction of heat supplied used for external work is

The temperature of a gas is doubled (i) on absolute scale (ii) on centrigrade scale. The increase in root mean square velocity of gas will be

• more in case (i).

• more in case (ii).

• same in both case.

• information not sufficient.

At standard temperature and pressure the density of a gas is 1.3 g m−3 and the speed of the sound in gas is 330 m s−1. Then the degrees of freedom of the gas is

• 3

• 4

• 5

• 6

A partition divides a container having insulated walls into two compartments I and II. The same gas fills the two compartments. The ratio of the number of molecules in compartments I and II is

• 1 : 6

• 6 : 1

• 4 : 1

• 1 : 4