Table of contents

1. The Chemical World9m
- The Scientific Method
  9m
2. Measurement and Problem Solving2h 19m
3. Matter and Energy2h 15m
4. Atoms and Elements2h 33m
5. Molecules and Compounds1h 50m
6. Chemical Composition1h 23m
7. Chemical Reactions1h 43m
8. Quantities in Chemical Reactions1h 8m
9. Electrons in Atoms and the Periodic Table2h 32m
10. Chemical Bonding2h 10m
11 Gases2h 7m
12. Liquids, Solids, and Intermolecular Forces1h 11m
13. Solutions3h 1m
14. Acids and Bases2h 14m
15. Chemical Equilibrium1h 27m
16. Oxidation and Reduction1h 33m
17. Radioactivity and Nuclear Chemistry53m

3. Matter and Energy

Physical & Chemical Changes

Introduction to Chemistry

3. Matter and Energy

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 change in chemical composition or just a change in physical form.

Consider the option 'Milk sours when left out of the refrigerator'. This involves a chemical change because new substances are formed as the milk spoils.

Look at the option 'Tums (containing CaCO3) neutralizes stomach acid'. This is a chemical change because it involves a reaction between calcium carbonate and stomach acid, producing new substances.

Evaluate the option 'Tearing a piece of paper'. This is a physical change because the paper is only changing its shape and size, not its chemical composition.