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

1. Intro to General Chemistry

Classification of Matter

General Chemistry

1. Intro to General Chemistry

Classification of Matter

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Multiple Choice

Which of the following is an example of a pure substance?

Salt water

Sand

Air

Carbon dioxide

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Verified step by step guidance

Understand the definition of a pure substance: A pure substance is a material that has a constant composition and has consistent properties throughout the sample. It is composed of only one type of particle.

Identify the characteristics of mixtures: Mixtures are composed of two or more different substances that are physically combined. They can be homogeneous (uniform composition) or heterogeneous (non-uniform composition).

Examine each option: Salt water is a mixture of salt (sodium chloride) and water, making it a homogeneous mixture. Sand is a heterogeneous mixture of different particles, such as minerals and rock fragments. Air is a homogeneous mixture of gases, including nitrogen, oxygen, and other trace gases.

Recognize that carbon dioxide (CO₂) is a pure substance: Carbon dioxide is a chemical compound consisting of one carbon atom and two oxygen atoms. It has a fixed composition and distinct chemical properties, making it a pure substance.

Conclude that carbon dioxide is the correct answer: Based on the definition of a pure substance, carbon dioxide fits the criteria as it is composed of only one type of molecule, CO₂, with a consistent composition.