Which of the following is a correctly balanced equation?

a.
2Cu + O2 → 2CuO

b.
2Cu + 2O2 → 2CuO

c.
Cu + O2 → 2CuO

d.
4Cu + O2 → 2CuO

1 answer

which is the only one with the same number of atoms of Cu and O on both sides?
Note that they all have 2 Cu and 2 O on the right.