Please help with this chemistry question.?

Question

2.37 Phosphorus forms two compounds when it reacts with oxygen. In one compound, there are 1.00

grams of phosphorus for every 1.30 grams of oxygen, and in the other compound, there are 1.00 grams of

phosphorus for every 0.77 grams of oxygen. Show how these compounds illustrate the law of multiple

proportions.

I dont really get it :(

Answer 1

1 g P = 1.00 g/30.975 g/mol = 0.03228 mol P atoms

1.3 g O = 1.30 g/16.00 g/mol = 0.08125 mol O atoms

ratio P:O = 1:2.5

P2O5

1 g P = 1.00 g/30.975 g/mol = 0.03228 mol P atoms

0.77 g O = 0.77 / 16.00 g/mol = 0.04812 mol O atoms

ratio P:O = 1:1.5

P2O3