Question

If 1.0 g of each of the following gases is taken and kept under the same conditions
of temperature and pressure, which will occupy the smallest volume?

A.H2 B.CH4 C.N2 D.CO2

Answer 1

Answer:

CO2

Explanation:

no. of moles of CO2 is least in these four compounds for same mass.so it will occupy least volume

Answer 2

Given: 1 g of each of the gases H2, CH4, N2 and CO2 is taken and kept under same conditions of temperature and pressure.

To find: The gas that occupies the least volume

Explanation: The ideal gas equation that has to be used is PV= nRT where P is pressure, V is volume, R is gas constant, T is temperature and n is the number of moles.

Here, it is given that the pressure and temperature is constant for all gases. It means that volume is directly proportional to the number of moles.

Number of moles of H2

= given mass/ Molar mass of H2

= 1/2

= 0.5

Number of moles of CH4

= given mass/ Molar mass of CH4

= 1/16

= 0.0625

Number of moles of N2

= given mass/ Molar mass of N2

= 1/28

= 0.0357

Number of moles of CO2

= given mass/ Molar mass of CO2

= 1/44

= 0.0227

Clearly, the number of moles of CO2 is least among all the gases which means volume occupied by CO2 is also the least.

Therefore, option (D) CO2 occupies the smallest volume.