What is the total number of oxygen atoms on the right-hand side of this chemical equation?

The chemical equation is

Cu (s) + 4HNO3 (aq) ⇒ Cu (NO3) 2 (aq) + 2NO2 (g) + 2H2O (g)

Answer:

12

Explanation:

In the right hand side of the equation, there are three compound which contains O2, which are;

Cu (NO3) 2, number of oxygen atoms = 3*2 = 6

2NO2, number of oxygen atoms = 2*2=4

2H2O, number of oxygen atoms = 2*1=2

Total number of oxygen atoms on the right side of equation = 6+4+2 = 12