Question

How do you balance nitrogen monoxide + oxygen -> nitrogen dioxide

Answer 1

The unbalanced reaction looks like:

$NO + O_2 = NO_2;$

First of all, we need to balance oxygen molecules: we place 2 before NO₂. After that we need to balance nitrogen: we place 2 before NO.

$2NO + O_2 = 2NO_2;$

As we see, now the equation is balanced - the amounts of atoms in the left and the right parts of the equation are equal.