A gas mixture is made by combining 7.0 g each of Ar, Ne, and an unknown diatomic gas. At STP, the mixture occupies a volume of 16.60 L. What is the molar mass of the unknown gas?

Question

36626 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-11-17T13:00:18

Considering molar mass of

$Ar->40" g/mol"$

$Ne->20" g/mol"$

$"Molar mass of unknown gas"->m" g/mol"$

The total number of moles Ar , Ne and unknown gas in the gas mixture each having mass of 7g is

$=(7/40+7/20+7/m)mol$

Total Volume of these three gases at STP is

$(7/40+7/20+7/m)molxx22.4L/"mol"=16.60L$

$=>(7/40+7/20)22.4L+7/mxx22.4L=16.60L$

$=>21/40xx22.4+7/mxx22.4=16.60$

$=>11.76+7/mxx22.4=16.60$

$=>7/mxx22.4=(16.60-11.76)=4.24$

$=>m=(7xx22.4)/4.24~~36.98"g/mol"$