1. Which of the following is a characteristic of a physical change?
A. A new substance is formed.
B. The chemical composition remains the same.
C. It is usually irreversible.
D. Light or heat is always produced.
2. What happens during a chemical change?
A. The substance only changes its shape.
B. The atoms are rearranged to form new substances.
C. The substance changes from a solid to a liquid.
D. The total mass of the substance increases.
3. Which process is an example of a physical change?
A. Burning a piece of paper.
B. Baking a cake in the oven.
C. Melting an ice cube.
D. Digestion of food in the stomach.
4. Which of these is a clear indicator that a chemical change has occurred?
A. Change in state (e.g., solid to liquid).
B. Formation of a precipitate.
C. Change in size.
D. Dissolving sugar in water.
5. When iron reacts with oxygen to form rust, what kind of change is it?
A. Physical change.
B. Chemical change.
C. Change in state.
D. Phase change.
6. Cutting a wooden log into small chips is a physical change because...
A. The wood changes into a new material.
B. The color of the wood changes.
C. Only the shape and size change, not the identity.
D. It releases energy in the form of heat.
7. Which of the following is NOT a sign of a chemical reaction?
A. Evolution of a gas (bubbles).
B. Change in temperature.
C. Change in shape.
D. Production of an odor.
8. Is dissolving salt in water a physical or chemical change?
A. Chemical, because the salt disappears.
B. Physical, because the salt can be recovered by evaporation.
C. Chemical, because a new liquid is formed.
D. Physical, because the water changes color.
9. What type of change occurs when a candle burns?
A. Only physical change.
B. Only chemical change.
C. Both physical and chemical change.
D. No change occurs.
10. Which of the following describes a chemical property?
A. Density.
B. Boiling point.
C. Flammability.
D. Solubility.
11. Baking soda reacting with vinegar to produce carbon dioxide gas is a...
A. Physical change.
B. Chemical change.
C. Change of state.
D. Reversible process.
12. The process of sublimation (e.g., dry ice turning into gas) is a...
A. Chemical change.
B. Physical change.
C. Chemical reaction.
D. Permanent change.
13. Which statement is true about the Law of Conservation of Mass?
A. Mass is lost during a chemical change.
B. Mass is gained during a physical change.
C. Mass stays the same in both physical and chemical changes.
D. Mass only stays the same in physical changes.
14. Which of these is a chemical change?
A. Breaking a glass bottle.
B. Sharpening a pencil.
C. Fireworks exploding.
D. Mixing sand and water.
15. A slice of apple turning brown when left out in the air is an example of...
A. A physical change due to temperature.
B. A chemical change called oxidation.
C. A change in state.
D. Evaporation of water from the apple.
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