# Using the the equation 2Cu +O_2 -> 2CuO, how many grams of copper must react if 3.18 moles of CuO are produced?

The equation explicitly tells you that $2 \times 63.55 \cdot g$ copper metal reacts with $32.0 \cdot g$ dioxygen gas to form $2 \times 79.55 \cdot g$ $C u O$.
You have finished with $3.18 \cdot m o l$ $C u O$. How many moles of copper were necessary? And how many grams?