Question

A sample of 0.370 mol of a metal oxide (m2o3) weighs 55.45 g. how many grams of o are in the sample?

Answer 1

0.370 mol metal oxide = 55.45 g 

1 mol = 55.45/0.370 = 149.86 g 

in 1 mol there are 3 mol O = 16 * 3 = 48 g of O 

there is 48/149.86 * 100% O in the sample 

the sample has 48/149.86 * 0.370 = 0.119 g O