What is the molar mass of a gas if 40.0 L of the gas has a mass of 36.0 g at 740.torr and 30.0^°C?

Question

Quizplus · Accepted Answer

We need to use the ideal gas law to solve the problem, which states:

PV = nRT

where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature in Kelvin.

We can rearrange the equation to solve for the number of moles:

n = PV/RT

We are given the volume (40.0 L), the pressure (740.0 torr), and the temperature (30.0°C = 303.15 K). We can also convert the mass to moles using the molar mass (M) of the gas:

n = m/M

So we have:

m/M = PV/RT

M = mRT/PV = (36.0 g)(0.0821 L·atm/mol·K)(303.15 K)/(740.0 torr)(40.0 L) = 23.0 g/mol

Therefore, the molar mass of the gas is 23.0 g/mol, which corresponds to choice C.

What Is the Molar Mass of a Gas If 40