The balanced equation for the combustion of C3H6O (propanal) is:

2 C3H6O + 9 O2 → 6 CO2 + 6 H2O

Here's how to balance it:

1. Identify the reactants and products:

* Reactants: Propanal (C3H6O) and Oxygen (O2)

* Products: Carbon dioxide (CO2) and Water (H2O)

2. Start balancing the carbon atoms: There are 3 carbon atoms on the left side and 1 on the right. Add a coefficient of 3 in front of CO2.

* 2 C3H6O + 9 O2 → 6 CO2 + 6 H2O

3. Balance the hydrogen atoms: There are 12 hydrogen atoms on the left side and 12 on the right, so they are already balanced.

4. Balance the oxygen atoms: There are 18 oxygen atoms on the left side and 18 on the right. The equation is now balanced.

This balanced equation shows that 2 moles of propanal react with 9 moles of oxygen to produce 6 moles of carbon dioxide and 6 moles of water.