Question

1. what is thermochemistry?
2. if energy in the system (reactants) decreases, where does the energy go?
3. what type of change is it when energy is released?
4. if energy in the system increases, from where is the energy absorbed?
5. what type of change is it when energy is absorbed?
6. label the reaction processes in the image below.
7. what type of reaction is it when the radiant energy from the sun is changed to chemical energy in glucose molecules?
8. what type of reaction is it when animals obtain chemical energy in the form of glucose?

Explanation:

1. Thermochemistry is the study of heat changes that occur during chemical reactions and physical changes of state.
2. If energy in the system (reactants) decreases, the energy is released to the surroundings, usually in the form of heat.
3. When energy is released, it is an exothermic change. Heat is given off to the surroundings.
4. If energy in the system increases, the energy is absorbed from the surroundings, often in the form of heat.
5. When energy is absorbed, it is an endothermic change. Heat is taken in from the surroundings.
6. Left - exothermic (since energy of system decreases and is released to surroundings); Right - endothermic (since energy of system increases and is absorbed from surroundings).
7. The conversion of radiant energy from the Sun to chemical energy in glucose molecules is a photosynthesis reaction, which is an endothermic reaction as it absorbs energy from sunlight.
8. When animals obtain chemical energy in the form of glucose, they undergo cellular respiration, which is an exothermic reaction as energy is released during the breakdown of glucose.

Answer:

1. The study of heat changes in chemical reactions and physical state - changes.
2. Released to the surroundings.
3. Exothermic change.
4. Absorbed from the surroundings.
5. Endothermic change.
6. Exothermic; Endothermic
7. Endothermic reaction (photosynthesis).
8. Exothermic reaction (cellular respiration).