. Write the unbalanced chemical equation.
Left would be the reactant side, while right would be the product side.
C3H8 + O2 ---> H2O + CO2
2. Start by balancing elements which is NOT Hydrogen or Oxygen. Hydrogen should be second to the last and Oxygen last.
As we can see, Carbon is not balanced. There are 3 carbon atoms while in the product side, only one. So to balance it, we need to write 3 as a stoichiometric coefficient. It is the number in the front of a compound.
This will now be:
C3H8 + O2 ---> H2O + 3CO2
3. Next, we're now only left with H and O, we must first balance Hydrogen. In the reactant side, there are 8 H atoms, while, there are only 2 H atoms at the right. So in order to make 2, eight, we need to multiply it by 4. So you have to put a coefficient in front of H in the product side.
C3H8 + O2 ---> 4H2O + 3CO2
4. Now, we finally balance O. In the left, there are 2 atoms while at the right, Oxygen has 4 atoms in H2O plus 6 atoms in CO2 (3*2) so at the product side, we have 10 atoms at the product side.
To balance it, we'll need to multiply 2 by 5 in the reactant side.
C3H8 + 5O2 ---> 4H2O + 3CO2
hope it helps a bit!!!