Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 38m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

8. Thermochemistry

Endothermic & Exothermic Reactions

General Chemistry

8. Thermochemistry

Endothermic & Exothermic Reactions

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Multiple Choice

Which of the following reactions is exothermic?

Photosynthesis

Evaporation of water

Melting of ice

Combustion of methane

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Verified step by step guidance

Understand the concept of exothermic reactions: Exothermic reactions are chemical reactions that release energy, usually in the form of heat, to the surroundings. This is often observed as an increase in temperature of the surroundings.

Identify the nature of each given reaction: Photosynthesis, evaporation of water, and melting of ice are processes that absorb energy from the surroundings, making them endothermic. Combustion of methane, however, releases energy, making it exothermic.

Examine the combustion of methane: The chemical equation for the combustion of methane is \( \text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O} \). This reaction releases energy as heat and light, indicating it is exothermic.

Compare the energy changes: In exothermic reactions like the combustion of methane, the energy released from forming the products is greater than the energy required to break the reactants' bonds.

Conclude that the combustion of methane is exothermic: Based on the energy release and the nature of the reaction, combustion of methane is the correct answer as an exothermic reaction.