CHEMISTRY COMMUNITY

Hello, I am having trouble solving problem H17 of the homework.

Balance C7H16->CO2H2O.

Since there is an oxygen atom in the product and none in the reactants, is it accurate/allowed to add oxygen atoms to the reactant?

In the reactants, there is an O2.

There actually is an O2 in the reactants. if you reread the question, it states that the reaction is a combustion with oxygen gas and liquid heptane!

This reaction is a combustion reaction, so O2 would be one of the reactants. Therefore, the chemical equation would be O2 + C7H16 -> CO2 + H2O. You would first balance the carbon, so you would put 7 as the stoichiometric coefficient in front of the carbon dioxide on the products side. Then, you would balance hydrogen, so since there are 16 hydrogens on the reactants side, you would need to put an 8 in front of the H2O on the product side. Finally, you would balance oxygen. On the products side, there would be 22 oxygen. So, you would need to balance the reactants side of the equation by putting 11 in front of the O2. Your final balanced chemical equation would be 11O2 + C7H16 -> 7CO2 + 8H2O.

make sure when writing down chemical formulas you don't miss any parts. Take your time with the question. The final answer should've been 11O2 + C7H16 -> 7CO2 + 8H2O.

Be sure to pay attention to what type of reaction it is, so you don't miss anything important for the equation. You can't just add oxygen atoms to the reaction unless it's given (which it is for H17 :))