You're trying to balance the combustion reaction of butane (C4H10) with oxygen (O2). Here's how to do it:

1. Write the Unbalanced Equation:

C4H10 + O2 → CO2 + H2O

2. Balance the Carbon Atoms:

There are 4 carbon atoms on the left side (in C4H10) and 1 on the right side (in CO2). Put a 4 in front of CO2:

C4H10 + O2 → 4CO2 + H2O

3. Balance the Hydrogen Atoms:

There are 10 hydrogen atoms on the left side (in C4H10) and 2 on the right side (in H2O). Put a 5 in front of H2O:

C4H10 + O2 → 4CO2 + 5H2O

4. Balance the Oxygen Atoms:

There are 2 oxygen atoms on the left side (in O2) and 13 on the right side (8 from 4CO2 and 5 from 5H2O). Put a 13/2 in front of O2:

C4H10 + 13/2 O2 → 4CO2 + 5H2O

5. Eliminate Fractions (Optional):

To get rid of the fraction, multiply the entire equation by 2:

2C4H10 + 13O2 → 8CO2 + 10H2O

Balanced Equation:

The balanced chemical equation for the combustion of butane is:

2C4H10 + 13O2 → 8CO2 + 10H2O