1. Balance the following equations:
a. -
C8H18(1) + ___02(g) +
CO2(g) +
H2O(1)

1. 2C8H18 + 25O2 —> 16CO2 + 18H2O

2. The coefficient of O2 is 25

Explanation:

C8H18 + O2 —> CO2 + H2O

The above equation can be balance as follow:

There are 8 atoms of C on the left side and 1 atom on the right side. It can be balance by putting 8 in front of CO2 as shown below:

C8H18 + O2 —> 8CO2 + H2O

There are 18 atoms of H on the left side and 2 atoms on the right. It can be balance by putting 9 in front of H2O as shown below:

C8H18 + O2 —> 8CO2 + 9H2O

Now, there are a total of of 25 atoms of O on the right side and 2 atoms on the left side. It can be balance by putting 25/2 in front of O2 as shown below:

C8H18 + 25/2O2 —> 8CO2 + 9H2O

Multiply through by 2 to clear the fraction as shown below :

2C8H18 + 25O2 —> 16CO2 + 18H2O

Now the equation is balanced.

2. 2C8H18 + 25O2 —> 16CO2 + 18H2O

From the balanced equation above, the coefficient of O2 is 25