Questions about Exothermic and Endothermic Processes
Multiple-Choice Questions – Exothermic and Endothermic Processes
1. What is the main difference between exothermic and endothermic processes?
A) One creates new atoms, the other destroys them
B) One involves energy transfer, the other doesn’t
C) One absorbs energy, the other releases it
D) One only happens in solids, the other in gases
E) Both release energy in the same direction
2. In an exothermic reaction:
A) Energy is absorbed
B) Temperature of surroundings drops
C) ΔH is positive
D) Heat is released
E) Products have more energy than reactants
3. An endothermic reaction is characterized by:
A) Heat release
B) Light emission
C) Absorption of heat
D) No energy change
E) Constant pressure
4. Which of the following is not an exothermic process?
A) Condensation of steam
B) Combustion of propane
C) Freezing of water
D) Boiling of water
E) Neutralization of acid and base
5. Which of the following processes is endothermic?
A) Burning of wood
B) Freezing
C) Melting
D) Condensation
E) Iron rusting
6. In which process is energy released to the surroundings?
A) Sublimation
B) Boiling
C) Condensation
D) Melting
E) Evaporation
7. Which of the following best describes the energy profile of an endothermic reaction?
A) Energy of products is lower than reactants
B) No change in energy
C) Energy of products is higher than reactants
D) Energy constantly decreases
E) Energy of products equals that of reactants
8. What happens to the temperature of the surroundings during an exothermic reaction?
A) It decreases
B) It stays the same
C) It increases
D) It becomes extremely cold
E) It becomes neutral
9. Which of the following is most likely to be an endothermic reaction?
A) Lighting a candle
B) Dissolving ammonium chloride in water
C) Firework explosion
D) Combustion of methane
E) Condensation of water vapor
10. Which process is exothermic?
A) Evaporation
B) Melting
C) Boiling
D) Freezing
E) Photosynthesis
11. What is true about exothermic and endothermic processes?
A) They both release heat
B) They both absorb energy
C) Exothermic releases heat; endothermic absorbs it
D) Exothermic is chemical only; endothermic is physical only
E) Only exothermic processes require activation energy
12. When ΔH is negative, the process is:
A) Endothermic
B) Exothermic
C) Neither
D) Undefined
E) Both
13. Photosynthesis is:
A) Exothermic because it produces glucose
B) Endothermic because it releases heat
C) Exothermic because it releases energy
D) Endothermic because it absorbs sunlight
E) Not a chemical reaction
14. Which of the following involves both endothermic and exothermic steps?
A) Combustion
B) Boiling water
C) Dissolving salt in water
D) Rusting
E) Condensation
15. Which of these temperature changes indicates an endothermic process?
A) A chemical reaction heats the container
B) Surroundings feel warmer
C) System absorbs heat and feels cooler
D) Water freezes
E) Steam condenses on a surface
16. A chemical cold pack used for injuries functions through:
A) Exothermic reaction
B) Combustion
C) Endothermic process
D) Radiation
E) Thermogenesis
17. Which of these is an exothermic phase change?
A) Melting
B) Boiling
C) Sublimation
D) Condensation
E) Evaporation
18. An endothermic reaction typically results in:
A) Warmer surroundings
B) No temperature change
C) Cooler surroundings
D) Hot product formation
E) Light emission
19. Why is melting ice an endothermic process?
A) It occurs below freezing
B) It releases energy to the air
C) It absorbs heat to break molecular bonds
D) It is irreversible
E) It forms hydrogen bonds
20. What would a positive ΔH value tell you about a reaction?
A) It releases heat
B) It is exothermic
C) It absorbs heat
D) It produces a gas
E) It involves no energy change
Answers with Full Explanations
1. C – Exothermic releases energy; endothermic absorbs it.
2. D – Heat is released during exothermic reactions.
3. C – Endothermic reactions absorb heat from surroundings.
4. D – Boiling requires heat input, so it is endothermic.
5. C – Melting requires absorption of heat.
6. C – Condensation releases heat to the surroundings.
7. C – Products have higher energy in endothermic reactions.
8. C – Exothermic reactions increase the temperature around them.
9. B – Dissolving ammonium chloride is a classic endothermic process.
10. D – Freezing releases heat (exothermic).
11. C – Clear definition: exothermic = release, endothermic = absorption.
12. B – Negative ΔH indicates an exothermic process.
13. D – Photosynthesis absorbs sunlight → endothermic.
14. C – Some salt dissolving involves both energy absorption and release.
15. C – Endothermic reactions absorb energy, cooling surroundings.
16. C – Cold packs absorb heat via endothermic reactions.
17. D – Condensation releases energy (exothermic).
18. C – Heat is drawn from surroundings → feels cooler.
19. C – Energy is needed to overcome intermolecular forces.
20. C – Positive ΔH = heat absorbed = endothermic.
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