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

2. Atoms & Elements

Law of Conservation of Mass

General Chemistry

2. Atoms & Elements

Law of Conservation of Mass

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Multiple Choice

Which of the following processes is an example of the Law of Conservation of Mass?

Photosynthesis converting carbon dioxide and water into glucose and oxygen

Melting of ice into water

Evaporation of water from a lake

Burning wood resulting in ash and smoke

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Verified step by step guidance

Understand the Law of Conservation of Mass: This law states that mass is neither created nor destroyed in a chemical reaction. The total mass of the reactants equals the total mass of the products.

Analyze each process: For each given process, determine if the mass of the substances before the process is equal to the mass of the substances after the process.

Photosynthesis: In this process, carbon dioxide and water are converted into glucose and oxygen. Write the balanced chemical equation: \( 6\text{CO}_2 + 6\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \). Check if the number of atoms of each element is the same on both sides of the equation.

Melting of ice: This is a physical change where ice (solid water) turns into liquid water. The mass of water remains the same before and after melting, but this is a physical change, not a chemical reaction.

Burning wood: This is a chemical reaction where wood reacts with oxygen to produce ash, smoke, and gases. The mass of the reactants (wood and oxygen) should equal the mass of the products (ash, smoke, and gases), but often gases escape, making it seem like mass is lost. This process can be tricky to measure accurately in terms of mass conservation.