States of Matter

A vessel contains 3.2 g of dioxygen gas at STP (273.15 K and 1 atm pressure). The gas is now transferred to another vessel at constant temperature, where pressure becomes one third of the original pressure. The volume of new vessel in L is : (Given : molar volume at STP is 22.4 L)

1. 67.2
2. 6.72
3. 2.24
4. 22.4

Four gas cylinders containing He, N2, CO2 and NH3 gases separately are gradually cooled from a temperature of 500 K. Which gas will liquefy first? (Given Tc in K – He : 5.3, N2 : 126, CO2 : 304.1 and NH3 : 405.5)

1. NH3
2. He
3. N2
4. CO2

Choose the correct option for graphical representation of Boyle's law, which shows a graph of pressure vs. volume of a gas at different temperatures :

1. [figure]
2. [figure]
3. [figure]
4. [figure]

Choose the correct option for the total pressure (in atm.) in a mixture of 4 g O2 and 2 g H2 confined in a total volume of one litre at 0 C is : [Given R = 0.082 L atm mol-1 K-1, T = 273 K]

1. 26.02
2. 2.518
3. 2.602
4. 25.18

A mixture of N2 and Ar gases in a cylinder contains 7 g of N2 and 8 g of Ar. If the total pressure of the mixture of the gases in the cylinder is 27 bar, the partial pressure of N2 is : [Use atomic masses (in g mol-1) : N = 14, Ar = 40]

1. 12 bar
2. 15 bar
3. 18 bar
4. 9 bar

A gas at 350 K and 15 bar has molar volume 20 percent smaller than that for an ideal gas under the same conditions. The correct option about the gas and its compressibility factor (Z) is -

1. Z < 1 and attractive forces are dominant
2. Z < 1 and repulsive forces are dominant
3. Z > 1 and attractive forces are dominant
4. Z > 1 and repulsive forces are dominant

Given van der Waals’ constant for NH3, H2, O2 and CO2 are respectively 4.17, 0.244, 1.36 and 3.59, which one of the following gases is most easily liquefied?

1. NH3
2. H2
3. O2
4. CO2

The correction factor ‘a’ to the ideal gas equation corresponds to

1. density of the gas molecules
2. volume of the gas molecules
3. electric field present between the gas molecules
4. forces of attraction between the gas molecules

Equal moles of hydrogen and oxygen gases are placed in a container with a pin-hole through which both can escape. What fraction of the oxygen escapes in the time required for one-half of the hydrogen to escape?

1. 3/8
2. 1/2
3. 1/8
4. 1/4

A gas such as carbon monoxide would be most likely to obey the ideal gas law at

1. low temperatures and high pressures
2. high temperatures and high pressures
3. low temperatures and low pressures
4. high temperatures and low pressures