Question

Two gas-filled tanks have the same volume, temperature, and pressure. They are identical in every way except that one is filled with oxygen (O2) gas and the other is filled with nitrogen (N2) gas. Which container weighs more?

Answer 1

Answer:

The tank with O₂ weighs more.

Explanation:

We can find the mass of gas using the ideal gas equation.

$P.V=n.R.T=\frac{m}{M} .R.T\\m=\frac{P.V.M}{R.T}$

Considering the pressure (P), volume (V), temperature (T) and ideal gas constant (R) are the same, we can establish that:

m ∝ M

The mass is directly proportional to the molar mass. The molar mass of O₂ (32 g/mol) is higher than the molar mass of N₂ (28 g/mol). Therefore, the tank with O₂ weighs more.