A. Choose the correct option.
1. Which of the following is true about atoms and molecules
a. They are very small. b. They are always in motion. C. They exert force on each other. D. All of these
Answer. D. All of these
2. What of the following is true about the features of particles of matter?
a. Very small particles always at rest, have space between them, and exert force on each other.
b. Very small, particles always at rest, have space in between them, and do not exert force on each other.
c. Very small particles, always in motion have space in between them, and do not exert force on each other.
d. Very small particles, always in motion have space in between them, and do not exert force on each other.
Answer. c. Very small, always moving, space between, exert force.
Q3. Which of the following can be used to determine whether a given substance is a solid, liquid or gas?
- Volume and area. b. Shape and length. C. Volume and shape. d. Shape and area.
Answer. c. Volume and shape
Q4. Which of the following states of matter has fixed volume and a fixed shape?
- Solid. b. liquid. C. Gas. d. All of these.
Answer. a. Solid
Q5. Which of the following states of matter can flow freely in every direction?
- Solid. b. liquid. C. Gas. d. All of these.
Answer. C. Gas
- Assertion and Reason question.
Q1. Assertion (A): Air is an example of matter.
Reason (R): Anything that has mass and occupies space is called matter.
- Both A and R are true. b. Both A and R are false. c. A is true and R is true. d. A is false and R is true.
Answer: a. Both A and R are true.
Air is matter because it has mass and fills space.
Q2. Question:
Assertion (A): Solids cannot be compressed.
Reason (R): The particles in a solid are loosely packed.
- Both A and R are true. b. Both A and R are false. c. A is true and R is true. d. A is false and R is true.
Answer: c. A is True and R is False
– Correction for R: The particles in a solid are tightly packed, not loosely packed.
c. True/False Statements
1. Anything that has mass and occupies space is called matter, not just a solid.
Answer. False
2. Gas particles move freely and do not have a fixed position.
Answer. False
3. Solid particles are arranged very close together.
Answer .True
4. Particles in liquids vibrate and slide over one another.
Answer. True
5. Gases are easy to compress, not difficult.
Answer. False
D. Match the Following
| Column A | Column B |
| Matter is composed of these | Solids |
| These take the shape of the container | b.Gases |
| These have the strongest inter-particle attraction | c.Powder |
| These have the greatest inter-particle distance | d. Particles |
| This form of solid can appear to flow like a liquid | e. Liquids |
1. d. Particles
2. e. Liquids
3. a. Solids
4. b. Gases
5. c. Powder
E. Give Reasons for the following.
Q1.Milk takes the shape of the glass it is poured into
Answer. Because it is a liquid, and liquids flow to take the shape of their container.
Q2. Containers without solids or liquids are not empty
Answer. They contain gas (like air), which is also matter.
Q3. A table has a fixed shape and volume –
Answer. It is a solid, and solids have tightly packed particles that do not move freely.
Q4. We can smell incense from a distance.
Answer. We can smell incense because gases diffuse and spread in all directions.
Q5. Gas needs a closed container, but liquid does not –
Answer. Gases need a closed container because they escape if not sealed, while liquids stay in place due to gravity.
Q6. Gases can be compressed easily. Answer. Gases can be compressed easily because gas particles have large spaces between them.
F. Short Answer Questions
Q1. Name three states of matter. Give two examples of each.
Answer. – Solid, e.g., wood, ice
Liquid, e.g., water, oil
Gas, e.g., oxygen, carbon dioxide
Q2. Explain the Difference between the arrangement of particles in liquids and gases with the help of diagrams.
Answer. Liquids: Particles are close but can slide past each other.
Gases: Particles are far apart and move freely.
Q3. Why do Gases expand to fill the container, whereas liquids do no, but liquids do not
Answer. Gas particles have weak forces and fill all space, while liquids have stronger forces and stay together.
Q4.Reema’s mother took a tall, thin glass and a flat cup and poured 200 ml of hot Chocolate into each. Reema took the tall, thin glass, thinking that it had more chocolate in each. Reema took a thin glass, thinking that it had more chocolate than the other. Which property of liquid is she missing here?
Question
Answer: Reema is missing the property that liquids take the shape of the container but do not change in volume. Both glasses have the same amount.
G. Long Answer Questions
Q1. Compare and contrast properties of solids, liquids, and gases:
Answer. Solids: Fixed shape/volume, strong forces, particles vibrate in place.
Liquids: No fixed shape takes the container shape, moderate forces, and particles slide.
Gases: No fixed shape/volume, weak forces, particles move freely.
Q2. Sugar can be made to flow from one tumbler to another. Do you think it is liquid? Explain the answer
Answer. No, sugar is a solid. It flows because its small grains move like a powder, but each grain is still a solid.
Q3. What would happen to the properties of particles of matter if Water is frozen to ice?
Answer. The particles change from loosely packed liquid to tightly packed solid, losing the ability to flow.
Q4. Table Completion:
| Object | Define Volume | Definite shape | Needs a container | Can be cut | Flows easily |
| Honey | |||||
| Helium | Yes | ||||
| Paper |
Answer.
| Object | Define Volume | Definite shape | Needs a container | Can be cut | Flows easily |
| Honey | Yes | No | yes | No | Yes |
| Helium | No | No | Yes | NO | Yes |
| Paper | yes | Yes | No | Yes | NO |