Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

In a chemical reaction, what happens to the atoms of the reactants?

1. They disappear and do not form products

2. They remain unchanged during the reaction

3. They rearrange to form new substances

4. They travel in straight lines

The correct answer is: They rearrange to form new substances

In a chemical reaction, the atoms of the reactants rearrange to form new substances. This process is a fundamental aspect of chemical reactions, as it illustrates the law of conservation of mass, which states that matter is neither created nor destroyed during a chemical reaction. Instead, the atoms present in the reactants are simply rearranged to create products. When a chemical reaction occurs, bonds between atoms in the reactants break and new bonds form to create different molecules, which are the products of the reaction. This concept is crucial in understanding how chemical reactions work and highlights the transformative nature of the interactions at the atomic level. The other options reflect misunderstandings of chemical processes. For instance, stating that atoms disappear ignores the conservation of mass principle, while saying that they remain unchanged doesn't account for the fact that bonds are broken and formed. Additionally, the idea that atoms travel in straight lines is not applicable in the context of chemical bonding and reactions, as the movement and interactions of atoms are influenced by forces and their environments during a reaction.