Answer:
6 atoms of carbon are in the reactant side
Explanation:
Are on the reactant side in:
6CO2 + 6H2O → C6H12O6 + 6O2
In the reaction, there are 6 molecules of CO2 that are reacting with 6 molecules of H2O. As you can see, CO2 has only 1 atom of carbon per molecule whereas H2O hasn't.
That means the atoms of carbon are:
6 molecules CO2 * (1atom C / 1molecule CO2) =
6 atoms of carbon are in the reactant side
