# Chemistry

posted by
**mZ. YoU** on
.

Can you balance this equation please?

Fe2O3 + CO yeilds Fe + CO2

Fe2O3 + CO ==> Fe + CO2

Rule: balance by changing coefficients. You may not change subscripts.

Look at the Fe atoms. There are 2 Fe atoms on the left and only 1 on the right; therefore, we place a 2 in front of the Fe on the right. Like so.

Fe2O3 + CO ==> 2Fe + CO2

Count O on the left. I see 4. That means I need a 2 in front of the CO2 on the right. Like so.

Fe2O3 + CO ==> 2Fe + 2CO2

But we see that by changing CO2 on the right, we automatically mess up the C on the left. So we place a 2 in front of the CO on the left and TRY IT. It may not work.

Fe2O3 + 2CO ==> 2Fe + 2CO2

Now we check. Fe balances with 2 on the left and right. C balances with 2 on the left and right. O does not balance because there are 5 on the left and 4 on the right. Alas! What to do? Since there is an odd number of O atoms on the left, sometimes it helps to try the next higher number; i.e., instead of 2 on the CO2, let's try 3 for CO2 (and of course that makes us use 3CO on the left. Like so.

Fe2O3 + 3CO ==> 3Fe + 3CO2

Now let's check it. 2 Fe on left and right. 6 O on the left (3 from Fe2O3 and 3 from 3CO) and 6 on the right (3x2=6). And we have 3C on the left and 3C on the right. Everything balances. Yea!

But you have 3 fe on the right and only two on the left because the 2 behind the Fe is a subscript for Fe so the equation is:

Fe subscript 2 O subscript 3 yeilds Fe plus CO subscript 2

Thank you for calling that to my attention. I just made a typo. Notice in the step BEFORE I had a 2 in front of the Fe on the right side. I meant to keep the old numbers but change the CO and CO2. When I typed the next step I typed a 3 instead of a 2 Fe on the right. The complete balanced equation should look this way.

Fe2O3 + 3CO ==> 2Fe + 3CO2

Looks ok to me now.

Thank you