To determine the number of carbon atoms (C) present in the reactants of the chemical equation:
2C6H10 + 17O2 → 12CO2 + 10H2O
You can break down each molecule and count the carbon atoms. In the reactants, you have two molecules of C6H10, so you need to count the carbon atoms in each molecule and then multiply by 2:
C6H10 contains 6 carbon atoms per molecule, so 2C6H10 will have:
2 molecules × 6 carbon atoms/molecule = 12 carbon atoms
So, there are 12 carbon atoms in the reactants. The correct answer is 12.