1. The mean kinetic energy of a gas at 300 K is 100 J. The mean energy of the gas at 450 K is equal to

a) 100 J

b) 3000 J

c) 450 J

d) 150 J

Explanation:

2. The capacity of a vessel is 3 litres. It contains 6 gm oxygen, 8 gm nitrogen and 5 gm \[CO_{2}\] mixture at 27°C. If R = 8.31 \[J/mole\times kelvin\] , then the
pressure in the vessel in \[N\diagup m^{2}\] will be (approx.)

a) \[5\times10^{5}\]

b) \[5\times10^{4}\]

c) \[10^{6}\]

d) \[10^{5}\]

Explanation:

3. In the absence of intermolecular force of attraction, the observed pressure P will be

a) P

b) < P

c) > P

d) Zero

Explanation: In the absence of intermolecular force of attraction, the observed pressure P will be > P

4. Two ideal gases at absolute temperature \[T_{1}\] and \[T_{2} \] are mixed. There is no loss of energy. The masses of the molecules are \[m_{1}\] and \[m_{2} \] and the number of
molecules in the gases are \[n_{1}\] and \[n_{2} \] respectively. The temperature of mixture will be

a) \[\frac{T_{1} + T_{2} }{2}energy\]

b) \[\frac{T_{1} + T_{2} }{n_{1} n_{2}}\]

c) \[\frac{n_{1}T_{1} +n_{2} T_{2} }{n_{1}+ n_{2}}\]

d) \[\left(T_{1} + T_{2}\right)\]

Explanation: \[\frac{n_{1}T_{1} +n_{2} T_{2} }{n_{1}+ n_{2}}\]

5. The molecules of an ideal gas at a certain temperature have

a) Only potential energy

b) Only kinetic energy

c) Potential and kinetic energy both

d) None of the above

Explanation: The molecules of an ideal gas at a certain temperature have only kinetic energy

6. Mean kinetic energy per degree of freedom of gas molecules is

a) \[\frac{3}{2}kT\]

b) kT

c) \[\frac{1}{2}kT\]

d) \[\frac{3}{2}RT\]

Explanation: Mean kinetic energy per degree of freedom of gas molecules is \[\frac{1}{2}kT\]

7. The temperature at which the average translational kinetic energy of a molecule is equal to the energy gained by an electron in
accelerating from rest through a potential difference of 1 volt is

a) \[4.6\times 10^{3}K\]

b) \[11.6\times 10^{3}K\]

c) \[23.2\times 10^{3}K\]

d) \[7.7\times 10^{3}K\]

Explanation:

8. The kinetic energy of one gm-mole of a gas at normal temperature and pressure is (R = 8.31
J/Mole-K)

a) \[0.56\times 10^{4}J\]

b) \[1.3\times 10^{2}J\]

c) \[2.7\times 10^{2}J\]

d) \[3.4\times 10^{3}J\]

Explanation:

9. The average kinetic energy of hydrogen molecules at 300 K is E. At the same temperature, the average kinetic energy of oxygen molecules will
be

a) E/4

b) E/16

c) E

d) 4 E

Explanation: The average kinetic energy of hydrogen molecules at 300 K is E. At the same temperature, the average kinetic energy of oxygen molecules will be E

10. The average translational kinetic energy of a hydrogen gas molecules at NTP will be
[Boltzmann’s constant \[K_{B}=1.38\times 10^{-23}J\diagup K\] ]

a) \[0.186\times 10^{-20}Joule\]

b) \[0.372\times 10^{-20}Joule\]

c) \[0.56\times 10^{-20}Joule\]

d) \[5.6\times 10^{-20}Joule\]

Explanation: