posted by annabel on .
A 1.8 mole sample of a compound weighs 195 g and is found to be 11.18% H and 88.82% C. What is
the molecular formula for the compound?
Take a 100 g sample which will give you
11.18 g H and 88.82 g C.
mols C = 88.81/12 = ?
mols H = 11.18/1 = ?
Now find the ratio of the two elements to each other. I obtained C2H3.
empirical mass = 27
mols = grams/molar mass
You have moles and grams, solve for molar mass.
Then molar mass = empirical mass*y
Substitute and solve for y and from that the molecular formula.