A mixture of $He$ (molar mass 4) and $CH X_{4}$ (molar mass 16) has a total mass of $10.0 g$ . At a total pressure of $1.0 atm$ the partial pressure of $He$ is $0.60 atm$ . The mass of $CH X_{4}$ in grams (two decimals) is

Numerical answer type, answer in g, tolerance 0.02.

Answer: 7.27 g

Mole fractions:

x_{He} = 0.60

x_{CH X_{4}} = 0.40

. Mass ratio

He : CH X_{4} = 0.60 \times 4 : 0.40 \times 16 = 2.4 : 6.4

. Mass of

CH X_{4} = 10.0 \times \frac{6.4}{8.8} = 7.2727 \approx 7.27 g