I think there are four total. This comes from adding the 1 O from the NO to 2O from the O2. However the oxygen needs to be balanced. Multiplying the left NO and the NO2 on the right side by 2 you get:2NO + 2O -> 2NO2 Left to Right:2 x 1 N =2N -> 2 x 1 N = 2N 2x(One) Oxygen+ O2 (Two Oxygen) = Four Oxygen or 4O Read more on Brainly - https://brainly.com/sf/question/6460084
