Question

0.817 grams of an unknown gas occupies 1.25 L at 27.0 C and a pressure of 765

mm Hg. Is the gas most likely methane (CH 4 ), ethane (C 2 H 6 ), propane or butane?
Show work to support your answer.

Answer 1

The gas is most likely methane (CH₄)

Further explanation

In general, the gas equation can be written

`\large{\boxed{\bold{PV=nRT}}}`

where

P = pressure, atm

V = volume, liter

n = number of moles

R = gas constant = 0.08205 l.atm / mol K

T = temperature, Kelvin

`\tt PV=(mass)/(M)RT\\\\M=(mRT)/(PV)=(0.817* 0.082* 300)/(1,00658* 1.25)=15.97\approx=16`

So the gas is most likely methane (CH₄ )