Posted by Brooke on .
what number should be placed in the blank to balance the equation C 3 H 8 + 50 2 > 3 CO 2 ___ H 2 O
I have been working on this Q for four hours and it is driving me CRAZY please HELP i hate chemistry or anything with numbers in it as a matter of fact.

Chemistry 
Dr Russ,
C3H8 + 02 > CO2 + H2O
There are two ways to balance an equation 1) by inspection 2) by maths. As you don't like numbers we will do it by inspection.
When balancing an equation look to see if there is an element on its own, in this case we have O as O2. So we can balance this last.
Start with the C atomss. There are three on the LHS so there must be three on the RHS.
C3H8 + 02 > 3CO2 + H2O
similarly there are 8 H atoms on the LHS so we need 8 H atoms on the RHS. We can achieve this by putting a 4 in fron of the H2O. There are 8 H atoms in 4 molecules of water.
C3H8 + 02 > 3CO2 + 4H2O
The last atom to balance are the O atoms. There are 6+4=10 O atoms on the RHS, so we need 10 O atoms on the LHS. There are 10 O atoms in 5 molecules of O2. So our balanced equation is:
C3H8 + 502 > 3CO2 + 4H2O