Question

The mystery compound CxHy is completely reacted with O2 to yield 44 gr CO2 and 18gr H2O. What is the empirical formula of CxHy?

I got : C1H2

How much O2 in grams was used in this reaction??

Answer 1

2CH2 + 3O2 ==> 2CO2 + 2H2O
mols CO2 = 44/44 = 1
mols O2 = 1 mol CO2 x (3 mols O2/2 mols CO2) = 1*3/2 = ?

You can check this to see you get the same number using water.'
mols H2O = 18/18 = 1
mols O2 = 1 mol H2O x (3 mols O2/2 mols H2O) = 1*3/2 = ?

Convert mols O2 to grams. grams = mols x molar mass = ?