5. The law of conservation of __ must be satisfied for a chemical equation to be balanced atoms moles mass proportions

## Step 1<br />The law of conservation of mass is a fundamental principle. It states that matter cannot be created or destroyed in an isolated system. This principle is particularly important when balancing chemical equations.<br /><br />## Step 2<br />In a balanced chemical equation, the number of atoms of each element is the same on both the reactant (left) side and the product (right) side. This is because the law of conservation of mass requires that the total mass of the reactants equals the total mass of the products.<br /><br />## Step 3<br />The other options, such as atoms, moles, and proportions, are not the correct answer because they do not directly relate to the law of conservation of mass. While atoms and moles are involved in the balancing of chemical equations, they are not the principle being conserved. Proportions are the relative amounts of reactants and products, but they do not represent the conservation of mass.