Which of the following statements is NOT true about what happens in all chemical reactions?

• A. Chemical bonds are broken and new bonds are formed.
• B. Energy is always absorbed during a chemical reaction.
• C. Atoms are rearranged to form new substances.
• D. The total mass of reactants equals the total mass of products.

Answer: (B)

Verified step by step guidance

1. Understand that in all chemical reactions, chemical bonds between atoms are broken and new bonds are formed to create different substances. This is a fundamental characteristic of chemical reactions.
2. Recognize that atoms are rearranged during chemical reactions, meaning the same atoms present in the reactants are reorganized to form the products, but no atoms are lost or gained.
3. Recall the Law of Conservation of Mass, which states that the total mass of reactants must equal the total mass of products in a chemical reaction, because matter is neither created nor destroyed.
4. Consider the energy changes in chemical reactions: energy can be either absorbed (endothermic) or released (exothermic), so it is not true that energy is always absorbed during a chemical reaction.
5. Conclude that the statement 'Energy is always absorbed during a chemical reaction' is NOT true for all chemical reactions, as some reactions release energy instead.