Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

1. Matter and Measurements

Physical & Chemical Changes

GOB Chemistry

1. Matter and Measurements

Physical & Chemical Changes

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Multiple Choice

Which of the following is a physical change?

Milk sours when left out of the refrigerator

Tums (containing CaCO₃) neutralizes stomach acid.

Sugar caramelizing when heated on a skillet.

Tearing a piece of paper.

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Verified step by step guidance

Understand the difference between physical and chemical changes. A physical change affects the form of a chemical substance, but not its chemical composition. In contrast, a chemical change results in the formation of one or more new substances with new chemical properties.

Examine each option to determine if it involves a physical or chemical change. For example, when milk sours, it undergoes a chemical change as new substances are formed.

Consider the process of Tums neutralizing stomach acid. This is a chemical change because it involves a reaction between calcium carbonate (CaCO3) and hydrochloric acid (HCl) in the stomach, producing new substances.

Analyze the caramelization of sugar. This is a chemical change because heating sugar causes it to break down and form new compounds, changing its chemical structure.

Identify tearing a piece of paper as a physical change. Tearing paper changes its shape and size but does not alter its chemical composition, making it a physical change.