[roneddy]

A sample of 1.5g of Copper (I) oxide and copper (II) oxide is heated in hydrogen gas to give 1.298g of pure copper metal. Calculate the percent composition by mass of the two copper compounds in the sample.

[Borek]

Please read the forum rules.

You have to show your attempts at solving the question to receive help. This is a forum policy, and we are not a free "we will do your homework" service.

[Hunter2]

A sample of 1.5g of Copper (I) oxide and copper (II) oxide is heated in hydrogen gas to give 1.298g of pure copper metal. Calculate the percent composition by mass of the two copper compounds in the sample.

You have to develop two equations.  You get information of the mass difference about oxygen. You can calculate the molecular weight of the mixture. You know the mole of copper and oxygen obtained.

[roneddy]

x=mass of CuO
y=mass of Cu2O

x+y=1.5 [1]
0.18=(x) (16/79.54) + (y) ( 16/143.08)

is this correct?

[Borek]

0.18=(x) (16/79.54) + (y) ( 16/143.08)

Please explain what these numbers are. Molar masses of copper oxides are obvious, but what are the others? Especially, what is the 0.18 on the left?