Derive the formula for nitric oxide if it contains 63.64% nitrogen.

Let us denote: a is the number of nitrogen atoms, b is the number of oxygen atoms, m is the molecular weight of the oxide.
The relative atomic mass of nitrogen is 14, oxygen is 16.
Let’s compose the following expressions:
0.6364 = 14 * a / m;
0.3636 = 16 * b / m;

Let us express the molecular weight from the expressions:
m = 14 * a / 0.6364 = 22a;
m = 16 * b / 0.3636 = 44b;

Let’s equate the obtained expressions:
22a = 44b; This means that a = 2, b = 1. The oxide formula is N2O.

Answer: The formula for nitric oxide is N2O.