How many atoms of Oxygen (O) in the reactants of the equation below:

6CO2 + 6H2O - -> C6H12O6 + 6O2

18

19

20

30

The correct option is 18

Explanation:

There are two reactant specie in the equation; carbon dioxide (CO₂) and water (H₂O). From the equation, there are 6 molecules of CO₂, hence the number of oxygen atoms from CO₂ is 6 * 2 = 12 and there are also 6 molecules of H₂O, hence the number of oxygen atoms from H₂O is 6 * 1 = 6.

The total number of oxygen atoms in the reactants is therefore 12 + 6 = 18

Answer: 18 atoms

Explanation: the reactant contains 6O2 and 6O and this gives a total of 18