Question

calculating mass quick check
which option correctly describes the reactants and products of a chemical reaction? (1 point)
the mass of the reactants must be equal to the mass of the products. the total number of moles of the reactants can be more or less than the total number of moles of the products
the mass of the reactants must be equal to the mass of the products. the total number of moles of the reactants must also be equal to the total number of moles of the products
the mass of the reactants can be more or less than the mass of the products. the total number of moles of the reactants can also be more or less than the total number of moles of the products
the mass of the reactants can be more or less than the mass of the products. the total number of moles of the reactants must be equal to the total number of moles of the products

Explanation:

According to the law of conservation of mass, the mass of reactants must equal the mass of products in a chemical reaction. However, the number of moles of reactants and products can vary. For example, in the reaction \(2H_2 + O_2
ightarrow 2H_2O\), the number of moles of reactants (\(2 + 1=3\) moles) and products (\(2\) moles) are different.

Answer:

The mass of the reactants must be equal to the mass of the products. The total number of moles of the reactants can be more or less than the total number of moles of the products.