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 best describes how energy is used in chemical reactions?

Energy is only released during the formation of chemical bonds.

Energy is absorbed during the formation of chemical bonds.

Energy is absorbed to break bonds and released when new bonds are formed.

Energy is neither absorbed nor released during chemical reactions.

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Verified step by step guidance

Understand that chemical reactions involve breaking and forming chemical bonds. Energy is required to break bonds, and energy is released when new bonds are formed.

Recognize that the process of breaking bonds is endothermic, meaning it absorbs energy. This is because energy is needed to overcome the forces holding the atoms together.

Identify that the process of forming new bonds is exothermic, meaning it releases energy. This occurs because the system releases energy as atoms come together to form stable bonds.

Consider the overall energy change in a chemical reaction, which is determined by the balance between the energy absorbed to break bonds and the energy released when new bonds are formed.

Conclude that the correct description of energy use in chemical reactions is: 'Energy is absorbed to break bonds and released when new bonds are formed.' This reflects the dynamic nature of energy changes during chemical reactions.