According to the Law of Conservation of Mass, the total mass of the reactants must equal the total mass of the products.
In this case, the mass of carbon (C) used in the reaction is 24 g, and the mass of carbon dioxide (CO2) produced is 88 g.
To find the mass of dioxygen (O2) in the reactants, you can set up the equation:
Mass of reactants = Mass of products
Let \( m \) be the mass of dioxygen (O2):
\[ m + 24 , \text{g (mass of carbon)} = 88 , \text{g (mass of CO2)} \]
Solving for \( m \):
\[ m = 88 , \text{g} - 24 , \text{g} = 64 , \text{g} \]
Therefore, the mass of dioxygen (O2) in the reactants is 64 g.