The combustion of 1.00g of vitamin C, compound that contains only carbon, hydrogen and oxygen produced 1.500g of co2 and 0.401g of H2O. Find the molecular formula of vitamin C knowing that its molecular mass is 176

Answer 1

g C = 1.500 g CO2 x (atomic mass C/molar mass CO2) = ?
g H = 0.401 g H2O x (2*atomic mass H/molar mass H2O) = ?
g O = 1.00-g C - g H = ?

Convert grams to mols.
mols C = g C/12 = ?
mols H = g H/1 = ?
mols O = g O/16 = ?

Find the ratio of the elements to each other with the smallest being 1.00. The easy way to do that is to divide the smallest number by itself which will give you 1.000 for that element. Then divide the other numbers by the same small number. The values you obtain can not be rounded to whole numbers so do this. Multiply each by 2,then 3, then 4, etc until you come up with values that can be rounded to whole numbers. I think you will find 3 ok. That will give you the empirical formula.
Now to find the molecular formula
Calculate the empirical formula mass. Then (176/empirical formula mass) = some number which I will call n. Round to a whole number. The molecular formula will be
(empirical formula)_n.
Post your work if you get stuck.