Answer:
2KNO3 + Na --> 2KO2 + NaO2 + N2
Step-by-step explanation:
on the left side there is 1 Nitrogen molecule, but on the right side there are 2.
So, by adding a coefficient of 2 on the left side the N balances out.
Then, the K's aren't balanced anymore. There are 2 K on the left and 1 K on the right.
So, if a coefficient of 2 is added to KO2 on the left, the K is then balanced.
Now check all the other molecules, and everything else is balanced!
On both sides there are 2 K's, 2 N's, 6 O's, 1 Na.