Which of the following best describes what thermochemistry involves?

• A. The classification of elements based on their atomic structure.
• B. The study of energy changes, especially heat, that occur during chemical reactions.
• C. The analysis of the rate at which chemical reactions occur.
• D. The measurement of the concentration of solutions in chemical reactions.

Answer: (B)

Verified step by step guidance

1. Understand that thermochemistry is a branch of chemistry focused on energy changes during chemical processes.
2. Recognize that it specifically deals with heat transfer and energy changes when substances undergo chemical reactions or physical changes.
3. Note that thermochemistry does not involve classifying elements, analyzing reaction rates, or measuring solution concentrations.
4. Recall that the key concept in thermochemistry is the study of heat (thermal energy) absorbed or released in reactions.
5. Conclude that the best description of thermochemistry is: the study of energy changes, especially heat, that occur during chemical reactions.