What is the volume of the sample?

Question

A sample of methane gas collected at a pressure of 342 mm Hg and a temperature of 299 K has a mass of 23.1 grams.

Answer 1

We can use the ideal gas law to solve:

PV = nRT

V = nRT/P

R = 0.0821 L*atm/K*mol (gas constant) T = 299 K P = 341 mmHg (1 atm / 760 mmHg) = 0.449 atm

Before we can solve for V, we need to know n, the moles of gas. We are given the mass of methane (CH₄), so we can use its molar mass (16.04 g/mol) to convert.

23.1 g CH₄ * (1 mol CH₄ / 16.04 g CH₄) = 1.440 mol CH₄

Now we can plug everything into our ideal gas law equation and solve for V:

V = (1.440 mol * 0.0821 L*atm/K*mol * 299 K) / (0.449 atm) = 78.79 L

Round for significant figures and your final answer is V = 78.8 L