In a chemical reaction, the law of conservation of mass states that the total mass of the reactants must equal the total mass of the products.
In this case, the scientist is starting with 30 grams of calcium carbonate (CaCO3). According to the balanced chemical reaction provided:
\[ \text{CaCO}_3 \rightarrow \text{CO}_2 + \text{CaO} \]
the total mass of the products will also be 30 grams, since the mass is conserved during the reaction.
Therefore, the correct response is:
30 grams
10 answers