The density of water is 1000 kg m^–3. The density of water vapour at 100 °C and 1 atm pressure is 0.6 kg m^–3. The volume of a molecule multiplied by the total number gives, what is called, molecular volume. The ratio (or fraction) of the molecular volume to the total volume occupied by the water vapour under the above conditions of temperature and pressure is:

1.  $5\times {10}^{-4}$

2.  $60\times {10}^{-4}$

3.  $50\times {10}^{-4}$

4.  $6\times {10}^{-4}$

The density of water is 1000 kg m^–3. The volume of a water molecule is:

1.  $4\times {10}^{-29} {\mathrm{m}}^3$

2.  $4\times {10}^{-28} {\mathrm{m}}^3$

3.  $3\times {10}^{-29} {\mathrm{m}}^3$

4.  $3\times {10}^{-29} {\mathrm{cm}}^3$

The density of water is 1000 kg m^–3. The density of water vapour at 100 °C and 1 atm pressure is 0.6 kg m^–3. What is the average distance between molecules (intermolecular distance) in water? (Given, the diameter of a water molecule in liquid state = 4 $\stackrel{\mathrm{o}}{\mathrm{A}}$)

1.  $47.45 \stackrel{\mathrm{o}}{\mathrm{A}}$

2.  $37.34 \stackrel{\mathrm{o}}{\mathrm{A}}$

3.  $20.23 \stackrel{\mathrm{o}}{\mathrm{A}}$

4.  $50.45 \stackrel{\mathrm{o}}{\mathrm{A}}$

A vessel contains two nonreactive gases: neon (monatomic) and oxygen (diatomic). The ratio of their partial pressures is \(3:2.\) The ratio of the number of molecules is:
(Atomic mass of Ne \(=20.2\) u, molecular mass of O₂ \(=32.0\) u)
1. \(2:3\)
2. \(3:2\)
3. \(1:3\)
4. \(3:1\)

A vessel contains two nonreactive gases: neon (monatomic) and oxygen (diatomic). The ratio of their partial pressures is 3:2. The ratio of mass density of neon and oxygen in the vessel is: (Atomic mass of Ne = 20.2 u, molecular mass of O₂ = 32.0 u).

1.  0.397

2.  0.937

3.  0.947

4.  1

A flask contains argon and chlorine in the ratio of 2:1 by mass. The temperature of the mixture is 27 °C. The ratio of average kinetic energy per molecule of the molecules of the two gases is: 

(Atomic mass of argon = 39.9 u; Molecular mass of chlorine = 70.9 u)

1.  1:2

2.  2:1

3.  1:1

4.  1:2

A flask contains argon and chlorine in the ratio of \(2:1\) by mass. The temperature of the mixture is \(27^{\circ}~\mathrm{C}\). The ratio of root mean square speed \(v_{rms}\) of the molecules of the two gases is: (Atomic mass of argon = \(39.9\) u; Molecular mass of chlorine = \(70.9\) u)
1. \(2.33\)
2. \(1.33\)
3. \(0.5\)
4. \(2\)

Uranium has two isotopes of masses 235 and 238 units. If both are present in Uranium hexafluoride gas, which would have the larger average speed?

Uranium has two isotopes of masses 235 and 238 units. If both are present in Uranium hexafluoride gas. If the atomic mass of fluorine is 19 units, what is the percentage difference in speeds of isotopes of Uranium at any temperature?

1.  0.43%

2.  0.34%

3.  0.55%

4.  Data insufficient

When a molecule (or an elastic ball) hits a ( massive) wall, it rebounds with the same speed. When a ball hits a massive bat held firmly, the same thing happens. However, when the bat is moving towards the ball, the ball rebounds at a different speed. Does the ball move faster or slower?