Question

1. As you increase the temperature of a gas in a sealed, rigid con-

tainer, what happens to the density of the gas? Would the results
be the same if you did the same experiment in a container with
a movable piston at a constant external pressure? Explain.

Answer 1

If one increases the temperature of a gas in a sealed, rigid container, the density of gas will not change.

The key to this answer lays in the ideal gas equation:

pV = nRT

Thus, one can write: n = (m)/(M)where m is the mass of the gas and M is the molar mass of a gas.

pV = (m)/(M) RT

Hence, if one decides to divide the entire equation with volume, V, one may write:

p = (m)/(VM) RT

ρ = (m)/(V), where ρ is density

p = (ρ)/(M) RT

If one increases the temperature, in order to keep balance, the pressure will be increased, also. Container is rigid, so that means the volume is constant.

However, this will not affect the density because there is no difference in volume (V = const.) or the amount of gas (n = const).

If one had a container with a piston, yet, constant pressure, the change of the temperature will impact the density.

Step-by-step explanation: