The Matter In Our Surroundings | Class IX | Chemistry | Questions and Answers |MBOSE| Part-1

Q.1. Which of the following constitute matter?

(Smell of roses, water, air, love, pain, idea, stone, table, sitar)

Answer: Water, air, table and sitar constitutes matter.

Q.2. A few substances are arranged in the increasing order of 'forces of attraction between their particles.

Which one of the following represents a correct arrangement? (a) Water, air, salt (b) air, sugar, oil (c) oxygen, water, sugar (d) salt, juice, air

Answer: Option (c) oxygen, water ,sugar

Explanation: Force of attraction is maximum in solid and least in gases.

Q.3. What do you understand by the term diffusion?

Answer: The intermixing of particles of two different substances on their own is called diffusion.

Q.4. In which state of matter, diffusion is: (a) fastest, (b) slowest?

Answer: (a) Gases

(b) Solids.

Q.5. Define the following: (a) intermolecular forces, (b) intermolecular spaces.

Answer: (a) The force of  attraction exists between the smallest particles of matter is called intermolecular forces.

(b) The spaces in between the molecules are called intermolecular spaces.

Q.6. In which states of matter, the intermolecular forces  are: (a) maximum, (b) minimum?

Answer: (a) The intermolecular forces are maximum in solid state.

(b) The intermolecular forces are minimum in gases.

Q.7. Write three characteristics of particulate nature of matter.

Answer: The three characteristics of particulate nature of matter are as follows-

1. Matter ( elements or compounds) consists of extremely small particles, which are not visible to the unaided eye.
2. The molecules are in the state of continuous motion.
3. Kinetic energy of the molecules increases with the rise in temperature and vice versa.

Q.8. Why does the smell of perfume of the incense stick fill the whole room in few minutes, when lighted?

Answer: When the incense stick is lighted, the heat energy makes the particles of perfume move rapidly. Thus, they easily drift through the air in the room and hence, we

can smell it anywhere in the room.

Q.9. How will you show the particulate nature of matter?

Answer: The particulate nature of matter refers to the fact that matter is composed of small particles such as atoms, molecules, or ions. There are several ways to demonstrate the particulate nature of matter:

Diffusion: One way to show the particulate nature of matter is by demonstrating diffusion, which is the movement of particles from an area of high concentration to an area of low concentration. A simple experiment involves placing a drop of food coloring in a glass of water. Over time, the food coloring will diffuse throughout the water, showing that the particles in the water are in constant motion.

Brownian motion: Brownian motion is the random movement of particles in a fluid due to collisions with other particles. This can be demonstrated by placing small particles such as pollen or smoke in a container of water or air. The particles will move around randomly, showing the particulate nature of matter.

Evaporation and condensation: Another way to demonstrate the particulate nature of matter is by showing the process of evaporation and condensation. When a liquid is heated, the particles gain energy and move faster, eventually breaking away from the liquid and becoming a gas. When the gas cools down, the particles lose energy and slow down, eventually condensing back into a liquid. This process demonstrates that matter is composed of small particles that can change states.

Filtration: Filtration is the process of separating a mixture of substances based on the size and shape of their particles. By passing a mixture through a filter, it is possible to separate particles of different sizes and show that matter is composed of discrete particles.

Overall, these experiments and demonstrations provide evidence for the particulate nature of matter and help to illustrate the behavior of particles in different states of matter.