Question

Balance this equation: 1. P4 + O2 ----> P2 + O5 2. C2H6 + O2 ----> CO2 + H2O

Answer 1

When balancing chemical equations, add only coefficients (never change the subscripts). Therefore, count the number of each ion on each side and see if you can add a number in front to make the ion count the same.

Answer 2

\[P _{4}+O _{2}--->P _{2}+O _{5}\]

Answer 3

Eg. For the first equation, you have 2 P ions on the right side and 4 P ions on the left. To make them the same, add a coefficient of 2 in front of the P2. Then count the O ions on each side. You have 5 on one side, and 2 on the other, therefore add a coefficient of 5 to O2 and a coefficient of 2 to O5 so that there'll be 10 oxygens on each side of the arrow. Give the other one a try.

Answer 4

I'm thinking..... put a 3 behind H2 O, and then a 2 in front of CO2. Does this sound right?

Answer 5

If you do that, you'd have balanced the C and H ions, but not the oxygens. You now have 7 oxygens on one side, and only 2 on the other. You may have to play around with the coefficients of the other compounds to balance out the O.

Answer 6

How do you do fractional coefficients work? I need 02 to get to that O7?

Answer 7

Coefficients can only be whole numbers, so look back at the equation and see if you can do anything to the 3H2O (since the 3 is what causes the odd number of oxygen ions). If you try doubling it, you would get 6H2O and in that case, you can add a 7 in front of the O2 to make it balanced. Now the other compounds are unbalanced, so try changing the coefficients for them. Balancing equations is really just a lot of guesswork, but you get better at them the more you practice.