Question

Calculate the percentage by mass of oxygen in the following compounds.
.
.
.
Part C
cocaine, C17H21NO4

%O = ________ %

Answer 1

Gravimeteric factor

(Molecular mass Oxygen/Molecular Mass cocaine)*100

Answer 2

What's a gravimetric factor?

Answer 3

Its just what the formula is called for figuring out amount of an element present in a compound
if you wanted to know how much oxygen is in cocaine this will give you the ratio of oxygen to cocaine
(Molecular mass Oxygen/Molecular Mass cocaine)

then you can just multiply that ratio by a mass of cocaine to figure what of that mass is made up by Oxygen

The formula is simply

[ (Molecular Mass of element)/(Molecular Mass of entire compound) ]*mass of compound = Mass of individual element in compound