A certain compound was found to have a molar mass of 32.042 g.?

Question

A 3.827 g sample of this compound was burned in pure oxygen gas. The measured amount of CO2 produced was 5.256 g, while that of H2O was 4.303 g. No other products were produced in the reaction.

How many moles of carbon were in the original sample that underwent combustion ?

Answer 1

compound x + O2 ----> CO2 + H2O

moles compound x: 3.827g/ 32.042g/mol = 0.119mol
moles CO2: 5.256g/ 44g/mol = 0.119mol
moles H2O: 4.303g/ 18g/mol = 0.239mol

to get mol ratio, divide results by the smallest number of moles. in this case, divide them by 0.119mol. you will then get mole ratio:

1 mole compound x, 1 mole CO2 and 2 mol H2O

so, your balance equation becomes:

compound x + 2O2 ----> CO2 + 2H2O

you will see in the above's equation that one mole of carbon in the original sample underwent combustion.