What is the molecular formula of each of the following compounds? (a) empirical formula HCO₂, molar mass = 90.0 g/mol

Video transcript

Hey everyone. So here we have the empirical formula of a compound which is C. Three H four N 20. And it has a molar mass of 168.15 g per mole. And we asked calculate the molecular formula. We know that the empirical formula is this the relative number of atoms. And for the molecular formula this gives us the actual number of atoms. So now we need to first find what number to multiply the subscript by to get the whole number ratios for the molecular formula. We can do this by using the formula X. Equal smaller mass about about the empirical mass. In the empirical mask fc three age four into L. It's three Time is swell like 011g plus four Times 1.008g plus two Times 14.007g plus 15 .999 grams. And this will give us 84 .08 g. So now if you plug it in we get X. Because 168.15 Divided by 0.8. And this will give us two. So now we need to multiply the subscript and empirical formula by two UFC three age four into oh And they give us 6 6 age eight in four 02. So for the molecular formula we get C. Sex H. Eight in four 02. Thanks for watching my video and I hope it was helpful