text: how many moles of   hydrogen   were in the original sample that underwent combustion ? a certain compound was found to have a molar mass of   32.042 g.   a   4.187 g   sample of this compound was burned in pure oxygen gas. the measured amount of   co2   produced was   5.751 g,   while that of   h2o   was   4.708 g.   no other products were produced in the reaction.  how many moles of   hydrogen   were in the original sample that underwent combustion ?    enter a numeric answer only, do not enter units. 1) determine the mass of carbon, hydrogen and oxygen. carbon: 5.751 g x (12 / 44) = 1.568 g hydrogen: 4.708 g x (2 / 18) = 0.523 g oxygen: 4.187 - 1.568 - .523 = 2.096 g  2) convert to moles. carbon: 1.568 / 12 = 0.131 mol hydrogen: 0.523 / 1 = 0.523 mol oxygen: 2.096 / 16 = 0.131 mol  3) divide each molar amount by the lowest value to obtain small integers carbon: 0.131 / 0.131 = 1 hydrogen: 0.523 l / 0.131 = 4 oxygen: 0.131 / 0.131 = 1  the empirical formula of the substance is (ch4o)n the atomic masses add up to 32, which is also the molar mass of the compound. therefore n=1 and we find ch4o as final result.