Help with H2 chemistry question

LastRide7 SG

70cm^3 of a mixture of methane and ethene were exploded in 200cm^3 of oxygen. The volume of the residual gases was found to be 130cm^3. On being shaken with sodium hydroxide, the final volume was found to be 35cm^3. What is the composition of the mixture?

A: Volume of methane : 20cm^3 | Volume of ethene : 50cm^3
B: Volume of methane : 35cm^3 | Volume of ethene : 35cm^3
C: Volume of methane : 45cm^3 | Volume of ethene : 25cm^3
D: Volume of methane : 50cm^3 | Volume of ethene : 20cm^3

Can someone explain to me on how to do this question?

UltimaOnline SG

Let x cm3 be the volume of methane, and (700-x)cm3 be the volume of ethene. Based on stoichiometry of the balanced combustion equations for both methane and ethene (separate equations!), you can work out the volume of CO2(g) generated, in terms of x. Equate this volume (in terms of x) with (130 - 35), and solve for x.

LastRide7 SG

Thank you so much for the explanation, that helps a lot :)

UltimaOnline SG

Thank you so much for the explanation, that helps a lot :)

You're welcome

Chemfreak022 SG

There is something wrong with the question. Did not mention the temperature where the volume of gases was measured.

Nelstar SG

There is something wrong with the question. Did not mention the temperature where the volume of gases was measured.

The usual r.t.p.