Which would have a larger mass, an iron bar before or after it rusts? can you explainCalculate the percent copper by mass in Copper(I) oxide and Copper(II) oxide.Thank you for your help :)
The question is, to be polite, vague.
I think it's the same don't you know : mass is conserved during a chemical reaction
I think after it rusts. Fe--Fe2O3, mass will increase since oxidized. Cu2O molecular weight is 64*2+16144, 128/144 % 89% CuO molecular weight is 64+1680 64/80 %80%
