Matter & Changes Around us Quiz

A student fills a glass bottle completely with water and seals it tightly. He then places it in a freezer. After a few hours, he finds that the bottle has changes from its original appearance. What is the best scientific explanation?

1. Water changes into gas, causing pressure inside the bottle to bulge the bottle.
2. Freezing makes water disappear, causing the bottle to collapse.
3. The bottle absorbs too much cold and breaks.
4. Water expands when it freezes, exerting pressure on the bottle.

Answer: (d) Water expands when it freezes, exerting pressure on the bottle.

Select the odd one out based on the type of change.

1. Cracking of glass
2. Sunrise and sunset
3. Beating of the heart
4. Changing seasons

Answer: (a) Cracking of glass

A scientist measures the temperature of a substance as it is heated. What is the best explanation for the flat section of the graph?

1. The substance is undergoing a phase change
2. The substance is cooling down before heating again.
3. The temperature sensor stopped working.
4. The substance becomes unreactive at that point.

Answer: (a) The substance is undergoing a phase change

Two students argue about stretching a spring. Student A says, "Stretching is irreversible because the shape is changing permanently." Student B says, "Stretching is reversible because the spring returns to its original shape when released."

1. Student A is correct because stretching always breaks the spring
2. Student B is correct because elastic materials return to their original form
3. Both are wrong because stretching is always a chemical change
4. Both are correct because stretching can be both reversible and irreversible

Answer: (d) Both are correct because stretching can be both reversible and irreversible

Your team is given four changes: 1. Combustion of fuel 2. Dissolving salt in water 3. Melting of metal 4. Rusting of iron You must group them as: Group A – Involves new substance formation Group B – Reversible and no new substance formed What is the correct grouping?

1. Group A: 2 and 3, Group B: 1 and 4
2. Group A: 1 and 2, Group B: 3 and 4
3. Group A: 1 and 4, Group B: 2 and 3
4. Group A: 1 and 3, Group B: 2 and 4

Answer: (c) Group A: 1 and 4, Group B: 2 and 3

A blacksmith heats a piece of iron until it glows red and then shapes it into a tool. What kind of change has taken place?

1. Slow and chemical change
2. Fast and physical change
3. Slow and physical change
4. Fast and chemical change

Answer: (b) Fast and physical change

A student performed an experiment where she heated a blue copper sulphate crystal until it turned white. When she added water to it, the blue colour reappeared. What can be concluded from this experiment?

1. Heating changed the substance permanently, making it a chemical change
2. The process was a physical change because the original blue colour could be restored
3. A new substance was formed, making it an irreversible chemical change
4. The colour change is evidence of a chemical reaction, making it a chemical change

Answer: (b) The process was a physical change because the original blue colour could be restored

When someone uses an aerosol spray can, the can often feels colder after the spray is released. Why does this happen?

1. The can loses heat because the liquid inside turns into a gas, and that process absorbs heat.
2. The can cools because the gas inside becomes a solid.
3. The can cools because the liquid inside gains heat
4. The can cools because the air outside of the can cools it down.

Answer: (a) The can loses heat because the liquid inside turns into a gas, and that process absorbs heat.

Choose the Correct Statements from the Following: A) Sublimation is an example of a chemical change. B) Water boiling is an irreversible change. C) Melting and freezing involve the same amount of energy but in opposite directions. D) Expansion and contraction occur only in metals.

1. C only
2. A and C
3. B and D
4. D only

Answer: (a) C only

A student performs two experiments: Experiment 1: Heating sugar in a test tube Experiment 2: Melting sugar on a hot plate Which inference is valid?

1. Both are irreversible
2. Both are reversible
3. Experiment 1 is irreversible, 2 is reversible
4. Experiment 1 is reversible, 2 is irreversible

Answer: (c) Experiment 1 is irreversible, 2 is reversible