Class 9 Science

Chapters

# Matter In Our Surroundings

### MCQs

Question:- 1. Which one of the following sets of phenomena would increase on raising the temperature?

1. Diffusion, evaporation, compression of gases
2. Evaporation, compression of gases, solubility
3. Evaporation, diffusion, expansion of gas
4. Evaporation, solubility, diffusion, compression of gasses

Answer: (c) Evaporation, diffusion, expansion of gas

Question:- 2. Seema visited a Natural Gas Compressing Unit and found that the gas can be liquefied under specific conditions of temperature and pressure. While sharing her experience with friends she got confused. Help her to identify the correct set of conditions

1. Low temperature, low pressure
2. High temperature, low pressure
3. Low temperature, high pressure
4. High temperature, high pressure

Answer: (c) Low temperature, high pressure

Question:3-The property to flow is unique to fluids. Which one of the following statements is correct?

1. Only gases behave like fluids
2. Gases and solids behave like fluids
3. Gases and liquids behave like fluids
4. Only liquids are fluids

Answer: (c) Gases and liquids behave like fluids

Question: -4. During summer, water kept in an earthen pot becomes cool because of the phenomenon of

1. diffusion
2. transpiration
3. osmosis
4. evaporation

Question: -5 -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?

1. Water, air, wind
2. Air, sugar, oil
3. Oxygen, water, sugar
4. Salt, juice, air

Question: -6 -On converting 25°C, 38°C and 66°C to kelvin scale, the correct sequence of temperature will be

1. 298 K, 311 K and 339 K
2. 298 K, 300 K and 338 K
3. 273 K, 278 K and 543 K
4. 298 K, 310 K and 338 K

Answer: (a) 298 K, 311 K and 339 K

Question: - 7. Choose the correct statement of the following

1. conversion of solid into vapours without passing through the liquid state is called vapourisation.
2. conversion of vapours into solid without passing through the liquid state is called sublimation.
3. conversion of vapours into solid without passing through the liquid state is called freezing.
4. conversion of solid into liquid is called sublimation.

Answer: (b) conversion of vapours into solid without passing through the liquid state is called sublimation.

Question: -8 -The boiling points of diethyl ether, acetone and n-butyl alcohol are 35°C, 56°C and 118°C respectively. Which one of the following correctly represents their boiling points in kelvin scale?

1. 306 K, 329 K, 391 K
2. 308 K, 329 K, 392 K
3. 308 K, 329 K, 391 K
4. 329 K, 392 K, 308 K

Answer: (c) 308 K, 329 K, 391 K

Question: -9 -. Which condition out of the following will increase the evaporation of water?

1. Increase in temperature of water
2. Decrease in temperature of water
3. Less exposed surface area of water
4. Adding common salt to water

Answer: (a) Increase in temperature of water

Question: -10 -In which of the following conditions, the distance between the molecules of hydrogen gas would increase?

1. Increasing pressure on hydrogen contained in a closed container
2. Some hydrogen gas leaking out of the container
3. Increasing the volume of the container of hydrogen gas
4. Adding more hydrogen gas to the container without increasing the volume of the container
1. (i) and (iii)
2. (i) and (iv)
3. (ii) and (iii)
4. (ii) and (iv)

## Matter in Our Surroundings

Anything that has both mass and volume is called matter. You can also say that anything which has mass and which occupies space is called matter.

## Is Matter Around Us Pure?

Elements and compounds are pure substances. All other substances are mixtures which means they are not pure substances.

## Atoms and Molecules

Read about law of conservation of mass, law of constant proportions and Dalton's atomic theory.

## Structure of Atoms

Atom is made of three particles; electron, proton and neutron. These particles are called fundamental particles of an atom or sub atomic particles.

## Cell: The Fundamental Unit of Life

A cell is capable of independent existence and can carry out all the functions which are necessary for a living being.

## Tissue

A groups of cells which is meant for a specific task is called tissue. Tissues are the first step towards division of labour in complex organisms.

## Diversity in Living Organisms

Without proper classification, it would be impossible to study millions of organisms which exist on this earth.

## Motion

If an object changes its position with respect to a reference point with elapse of time, the object is said to be in motion.

## Force & Laws of Motion

Force has numerous effects. Force can set a stationary body in motion. Force can stop a moving body.

## Gravitation

Earth attracts everything towards it by an unseen force of attraction. This force of attraction is known as gravitation or gravitation pull.

## Work & Energy

When force is exerted on an object and object is displaced, work is said to be done. It means work is the product of force and displacement.

## Sound

Sound is a type of energy. Sound travels in the form of wave from one place to another.

## Why Do We Fall Ill

Health is a state of physical, mental and social well being. A condition in which the affected person is unable to carry out normal activities is termed as disease.

## Natural Resources

Resources which are obtained from nature are called natural resources. Examples: Air, water, soil, wood, etc.

## Improvement in Food Production

Food security is said to exist when all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life.