# How would you balance the equation for the combustion of octane: C8H18(l)+O2(g)---->CO2(g)+H2O(l)?

##### 2 Answers

The complete combustion of any hydrocarbon gives carbon dioxide and water. I will represent the combustion of hexane.

#### Explanation:

Is this equation balanced? How do you know? How is the complete combustion of octane,

or

#### Explanation:

**First**, you need to tally all the atoms.

Based on the subscripts, you have

*left side:*

C = 8

H = 18

O = 2

*right side:*

C = 1

H = 2

O = 2 + 1 (do not add this up yet)

**Second**, find the easiest atom to balance. In this case, the

*left side:*

C = **8**

H = 18

O = 2

*right side:*

C = (1 x **8**

H = 2

O = (2 x

Since

**Third**, balance the next easiest atom.

*left side:*

C = **8**

H = **18**

O = 2

*right side:*

C = (1 x 8) = **8**

H = (2 x **18**

O = (2 x 8) + (1 x

Now all that is left is to balance are the

Thus,

*left side:*

C = **8**

H = **18**

O = (2 x **25**

*right side:*

C = (1 x 8) = **8**

H = (2 x 9) = **18**

O = (2 x 8) + (1 x 9) = **25**

But if you don't want fractions as coefficients, you can always multiply the WHOLE equation by 2.

=

Both answers are considered correct.