How many grams of methane gas (CH4) are in a 15.8-liter sample at 1.2 atmospheres and 27°C? Show all work used to solve this problem

12.31 g

Solution:

Let us suppose that the gas is acting ideally, then according to Ideal Gas Equation,

P V = n R T

Also,

n = Mass / M. mass = m / M

So,

P V = m/M R T

Solving for m,

m = P V M / R T

Data Given:

P = 1.2 atm

V = 15.8 L

M = 16 g/mol

T = 27 C + 273 = 300 K

R = 0.0821 atm. L/mol. K

Putting Values,

m = (1.2 atm * 15.8 L * 16 g/mol) / (0.0821 atm. L/mol. K * 300 K)

m = 12.31 g