Complete combustion of 0.858 g of compound X gives 2.63 g of cO2 and 1.28 g of water. What is the molar mass of X?

mass of CO2 = 2.630 g or since the molar mass of CO2 is 44g / mole we have
0.05976 moles of CO2 since there is 1 mole so C in CO2
we have 0.05976 moles of C or 0.718 g of C
mass of H2O = 1.280 g or since the molar mass of wateris 18 g / mol we have
0.07105 moles of H2O since there are2 moles of H in 1 moles of H2O =
0.14210 moles of H or 0.143 g of H
molar ratio of C : H = 0.05976 : 0.14210
mass of C+H = 0.861 g
or after dividing by the smallest 0.05976
molar ratio of C : H = 1.000 : 2.378
multiply by 3 to get whole numbers 3.000 7.134 :

empirical formula is C3H7
so minimum molar mass is 43g / mol