[Manni]

A 0.732 g mixture of methane and ethane is burned yielding 2.064 g of CO2. What is the percent composition of this mixture a) by mass and b) on a mole basis.

Hey, I'm wondering how to approach this question. Tried a lot of different things, none of them worked. Help?

[Borek]

Assume m_m and m_e to be masses of methane and ethane respectively. Sum of these unknowns is given - that's one equation. Express mass of produced carbon dioxide (hint: stoichiometry) in terms of these unknowns as well - that yields second equation. Two equations in two unknowns - solve.