Question

Moles:
1) A compound is made up using 1.2g carbon and 1.6g oxygen and 0.2g hydrogen. Find the empirical formula of the compound?
2) The molecular mass (molar mass) of this compound is known to be 120 g/mol. Find the molecular formula of the compound?

Answer 1

the Molecular Wt's of
1 mole of C is 12 g/ mol
1 mol of O is 16 g/ mol
and 1 mol of is 1 g/ml

can you see a connection??

Answer 2

Number 1.

n = m/M

1) Find the moles using the above formula for C, H and O.
2) Use the smallest moles you find in part 1) , divide all of them by this to get a ratio of C, H and O.
3) Whatever number you get is the number of each element in the compound.

__________________

Number 2.

Find your molar mass from the above C,H, O empirical formula to get your actual molar mass, and divide it by 120 g/mol, then times whatever number you get for this by every number of each element in the C, H, O empirical formula to get the molecular formula.

Answer 3

zpupster: Yes, thank you!
mariacristi: Thank you very much !