A gaseous mixture contains 50% helium and 50% methane by volume. What is the percent by weight of methane in the mixture ?

Question

A gaseous mixture contains 50% helium and 50% methane by volume. What is the percent by weight of methane in the mixture ? (A) 19.97% (B) 20.05 % (C) 50 % (D) 75 %

Tardigrade Admin · Accepted Answer

( textVol. of He/ textVol. of CH4)=(50/50)=(1/1) ( textNo. of molecules of He/ textNo. of molecules of CH4)=(1/1) ( textMass of He/ textMass of CH4)=(4/16)=(1/4) ∴ Percentage of CH4 in mixture (4/5)×100=80 %

Q. A gaseous mixture contains 50% helium and 50% methane by volume. What is the percent by weight of methane in the mixture ?

19.97%

20.05 %

50 %

75 %

80.03%

$\frac{Vol. of He}{Vol. of C H _{4}} = \frac{50}{50} = \frac{1}{1}$
$\frac{No. of molecules of He}{No. of molecules of C H _{4}} = \frac{1}{1}$
$\frac{Mass of He}{Mass of C H _{4}} = \frac{4}{16} = \frac{1}{4}$
$∴$ Percentage of $C H_{4}$ in mixture $\frac{4}{5} \times 100 = 80%$