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Question (21)

QN001061

Which of the following changes is reversible?

(A) Burning wood
(B) Rusting iron
(C) Evaporation of water
(D) Cooking vegetables

Correct Answer: C

Explanation:

Water vapour can condense back into water.

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Question (22)

QN001062

A clay toy is broken into smaller pieces. Why is this considered a physical change?

(A) The material remains clay
(B) A gas is produced
(C) Heat is evolved
(D) Chemical reaction occurs

Correct Answer: A

Explanation:

The substance remains unchanged.

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Question (23)

QN001063

Which of the following statements is true for all physical changes?

(A) They are always irreversible
(B) They always produce light
(C) No new substance is formed
(D) They always involve combustion

Correct Answer: C

Explanation:

Physical changes do not form new substances.

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Question (24)

QN001064

A student observes droplets on the outside of a cold bottle. Which process mainly causes this?

(A) Combustion
(B) Condensation
(C) Rusting
(D) Burning

Correct Answer: B

Explanation:

Water vapour condenses on the cold surface.

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Question (25)

QN001065

Which of the following changes involves only a temporary change in appearance?

(A) Folding paper fan
(B) Cooking noodles
(C) Burning leaves
(D) Formation of curd

Correct Answer: A

Explanation:

Folding changes only appearance temporarily.

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Question (26)

QN001066

Which process shows a physical change involving change of state?

(A) Ice cream melting
(B) Milk souring
(C) Digestion of food
(D) Burning coal

Correct Answer: A

Explanation:

Melting is a physical change of state.

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Question (27)

QN001067

Why is boiling water considered a physical change?

(A) Steam is harmful
(B) Water changes colour
(C) Water vapour can be condensed back to water
(D) Oxygen reacts with water

Correct Answer: C

Explanation:

The original substance can be recovered.

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Question (28)

QN001068

A student inflated two balloons. One was pricked with a pin. What makes this situation different from simply releasing air slowly?

(A) The balloon cannot return to original form after bursting
(B) New rubber is formed
(C) Air changes into another gas
(D) The balloon becomes heavier

Correct Answer: A

Explanation:

Bursting damages the balloon permanently.

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Question (29)

QN001069

Which of the following changes is mainly due to change in arrangement of particles, not formation of new particles?

(A) Rusting
(B) Melting butter
(C) Burning fuel
(D) Fermentation

Correct Answer: B

Explanation:

Melting changes only particle arrangement.

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Question (30)

QN001070

A student kept water in a freezer overnight. Which conclusion is correct?

(A) Water changed chemically into ice
(B) Ice is a different substance from water
(C) Only the state changed
(D) Water lost its mass completely

Correct Answer: C

Explanation:

Freezing changes liquid water into solid water only.

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Question (21)

Which of the following changes is reversible?

Explanation:

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Question (22)

A clay toy is broken into smaller pieces. Why is this considered a physical change?

Explanation:

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Question (23)

Which of the following statements is true for all physical changes?

Explanation:

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Question (24)

A student observes droplets on the outside of a cold bottle. Which process mainly causes this?

Explanation:

Link:

Question (25)

Which of the following changes involves only a temporary change in appearance?

Explanation:

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Question (26)

Which process shows a physical change involving change of state?

Explanation:

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Question (27)

Why is boiling water considered a physical change?

Explanation:

Link:

Question (28)

A student inflated two balloons. One was pricked with a pin. What makes this situation different from simply releasing air slowly?

Explanation:

Link:

Question (29)

Which of the following changes is mainly due to change in arrangement of particles, not formation of new particles?

Explanation:

Link:

Question (30)

A student kept water in a freezer overnight. Which conclusion is correct?

Explanation:

Link:

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