Question

How do you balance:
Fe203 + CO -> Fe + CO2?

Answer 1

this is an annoying one, but keep in mind that O can never be an odd number in the products. Fe can be anything, so balance it last. The trick is to make the total O on the left even by using a 3 with CO.

Answer 2

so what would it look like?

Answer 3

put a 3 by the CO, that makes 3 C and 6 O on the left. Put a 3 by the CO2, that makes 3 C and 6 O, you just need to put a 2 by the Fe on the right, and done!