How would you balance the following equation: CH3CH2CH3(g)+O2(g) --> CO2(g) + H2O(g)?

1 Answer
Dec 4, 2015

We can rewrite this as:

"C"_3"H"_8(g) + "O"_2(g) -> "CO"_2(g) + "H"_2"O"(g)C3H8(g)+O2(g)CO2(g)+H2O(g)

I would initially start with the number of carbons because the number of carbons in "CO"_2CO2 is even, and the number of oxygens in "O"_2O2 is also even.

"C"_3"H"_8(g) + "O"_2(g) -> 3"CO"_2(g) + "H"_2"O"(g)C3H8(g)+O2(g)3CO2(g)+H2O(g)

Then, I would realize that there are 88 hydrogens on the left, and I need 4xx24×2 on the right.

"C"_3"H"_8(g) + "O"_2(g) -> 3"CO"_2(g) + 4"H"_2"O"(g)C3H8(g)+O2(g)3CO2(g)+4H2O(g)

Lastly, I would balance the oxygen, because it is easy to only affect the number of oxygens. It only complicates things more to assign a number to "O"_2O2 first because you'll probably end up changing it again later.

color(blue)("C"_3"H"_8(g) + 5"O"_2(g) -> 3"CO"_2(g) + 4"H"_2"O"(g))C3H8(g)+5O2(g)3CO2(g)+4H2O(g)

Last confirmation:

"C"C: 1xx3 = 3xx11×3=3×1
"H"H: 1xx8 = 4xx21×8=4×2
"O"O: 5xx2 = 3xx2 + 4xx15×2=3×2+4×1

Since this cannot be reduced any further, this is good to go.