Answer:
8.9 grams of Cu (copper).
Step-by-step explanation:
We have a balanced equiation, so lets solve this by first converting the Cu₂O to moles and then use the equation coefficients to find the moles of Cu we should expect to find.
10 grams of Cu₂O is (10 g/(143.1 g/mole) =0.070 moles of Cu₂O.
The balanced equation promises that we'll obtain 8 moles of Cu for every 4 moles of Cu₂O. That's a molar ratio of 8/4 or 2 (moles Cu/mole Cu₂O).
Therefore: (0.070 moles of Cu₂O)*(2 moles Cu/mole Cu₂O) = 0.140 moles Cu.
(0.140 moles Cu)*(63.55 g/mole Cu) = 8.9 grams of copper
A lot of work for a little copper. Next time, try MgO. It would be fun to ignite it after the synthesis.