Here's how to balance the equation for the complete combustion of one mole of C3H7OH (propanol):

Unbalanced Equation:

C3H7OH + O2 → CO2 + H2O

Balancing the Equation:

1. Carbon (C): There are 3 carbon atoms on the left side and 1 on the right. Multiply CO2 by 3:

C3H7OH + O2 → 3CO2 + H2O

2. Hydrogen (H): There are 8 hydrogen atoms on the left side and 2 on the right. Multiply H2O by 4:

C3H7OH + O2 → 3CO2 + 4H2O

3. Oxygen (O): There are 3 oxygen atoms on the left side and 10 on the right. Multiply O2 by 9/2:

C3H7OH + 9/2 O2 → 3CO2 + 4H2O

4. Whole Number Coefficients: Since we usually use whole number coefficients, multiply the entire equation by 2 to get rid of the fraction:

2C3H7OH + 9O2 → 6CO2 + 8H2O

Answer: The coefficient for oxygen in the balanced equation is 9.