Question

Cu2S + O2- 2Cu +SO2

when 10.2 mol Cu2S react with oxygen, how many moles of Cu are formed?
path?

Answer 1

Look at the equation. The coefficients are not there because they look pretty.
1 mol Cu2S yields 2 mols Cu;
2 mol Cu2S yields 4 mols Cu;
5 mol Cu2S yields 10 mols Cu;
10 mol Cu2S yields 20 mols Cu.
Get the picture?
So 10.2 mol Cu2S yields ...... mols Cu.

Answer 2

so it is 20.4 mols cu???