Worksheet Solutions: Particulate Nature of Matter | Worksheets with Solutions for Class 8 PDF Download

Multiple Choice Questions

Q1. Which of the following statements is not correct for liquid state?
(a) Particles are loosly packed in the liquid state
(b) Fluidity is the maximum in the liquid state
(c) Liquids can be compressed
(d) Liquids take up the shape of any container in which these are placed
Ans: (b)
Fluidity is maximum in the gaseous state and not in the liquid state.

Q2. What happens to the particles of a solid when it is heated to its melting point?
(a) They move farther apart and become a gas
(b) They vibrate more vigorously and become a liquid
(c) They stop moving completely
(d) They compress closer together
Ans: (b)
When a solid is heated to its melting point, the particles vibrate more vigorously, weakening interparticle forces, and the solid transitions to a liquid.

Q3. Why do liquids take the shape of their container but not gases?
(a) Liquids have stronger interparticle attractions than gases
(b) Liquids have no interparticle spaces
(c) Gases have a fixed volume
(d) Liquids have maximum interparticle spacing
Ans: (a)
Liquids have slightly weaker interparticle attractions than solids, allowing particles to move and take the container’s shape, while gases have negligible attractions, causing them to fill the entire container.

Q4. What does Activity with potassium permanganate in water demonstrate?
(a) The compressibility of liquids
(b) The fixed volume of liquids
(c) The continuous motion of liquid particles
(d) The strong interparticle forces in liquids
Ans: (c)
Activity shows that potassium permanganate particles spread in water, indicating that water particles are in constant motion, causing diffusion.

Fill in the Blanks

Q2. The forces of attraction between the particles are _______ in solids, ______ in liquids and _________ in gases.
Ans: Maximum, intermediate, minimum

Q3. Solid, liquid and gas are called the three _______ of matter.
Ans: States

Q4. The smell of perfume gradually spreads across a room due to ______.
Ans: Diffusion

Q5. Gas molecules at higher temperatures have more _______ than at cooler temperatures.
Ans: Kinetic energy

Q6. Forces of attraction in liquids are _______ than in solid.
Ans: Weaker

Very Short Answer Questions

Q1. What are the basic building blocks of matter called?
Ans: Constituent particles.

Q2. Why do solids have a fixed shape?
Ans: Strong interparticle attractions hold particles in fixed positions.

Q3. What happens to sugar particles when dissolved in water?
Ans: They break into tiny particles and occupy spaces between water particles.

Q4. Why can gases be compressed easily?
Ans: Gases have large interparticle spaces that can be reduced under pressure.

Q5. What causes the fragrance of an incense stick to spread in a room?
Ans: Diffusion due to the constant motion of gas particles.

Short Answer Questions

Q2. A substance is in liquid state at room temperature and changes into gas upon heating. What will you call its gaseous state? 
Ans: The gaseous state of the substance is called vapour. Gaseous state of a substance which exists as liquid also is known as vapour.

Q3. What happens to the particles of sugar when it dissolves in water, and why can’t we see them anymore?
Ans: When sugar dissolves in water, it breaks down into its constituent particles, which are too small to be seen. These particles spread out and occupy the interparticle spaces between water particles, making the solution taste sweet but appear clear.

Q4. Why do solids like chalk and iron have a fixed shape and volume?
Ans: Solids have a fixed shape and volume because their constituent particles are closely packed and held together by strong interparticle attractions, allowing only vibrations and not free movement.

Q5. How does the interparticle spacing in liquids compare to that in solids, and what does this mean for their properties?
Ans: In liquids, interparticle spacing is slightly more than in solids, allowing particles to move past each other. This results in liquids having a definite volume but no fixed shape, as they take the shape of their container.

Q6. What role does heating play in changing a solid to a liquid, and what is this process called?
Ans: Heating increases the thermal energy of particles, causing them to vibrate more vigorously and weaken interparticle attractions. This process, where a solid turns into a liquid, is called melting, and it occurs at the melting point.

Q7. Why do gases fill the entire space of their container, unlike solids and liquids?
Ans: Gases have negligible interparticle attractions and maximum interparticle spacing, allowing their particles to move freely in all directions and occupy the entire available space.