We have provided Matter in Our Surroundings Class 9 Extra Questions With Answers to help students understand the concept very well. You can also practice Motion and Time Class 7 Extra Questions with Answers on cbsesamplepapers.info.

## Matter in Our Surroundings Class 9 Extra Questions With Answers

Question 1.
Which of the following phenomena would increase on raising the temperature?
(a) Diffusion, evaporation, compression of gases
(b) Evaporation, compression of gases, solubility
(c) Evaporation, diffusion, expansion of gases
(d) Evaporation, solubility, diffusion, compression of gases
(c) Evaporation, diffusion, expansion of gases

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.
(a) Low temperature, low pressure
(b) High temperature, low pressure
(c) Low temperature, high pressure
(d) High temperature, high pressure
(c) Low temperature, high pressure

Question 3.
The property of flow is unique to fluids. Which one of the following statements is correct?
(a) Only gases behave like fluids
(b) Gases and solids behave like fluids
(c) Gases and liquids behave like fluids
(d) Only liquids are fluids
(c) Gases and liquids behave like fluids

Question 4.
During summer, water kept in an earthen pot becomes cool because of the phenomenon of
(a) diffusion
(b) transpiration
(c) osmosis
(d) evaporation
(d) 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?
(a) Water, air, wind
(b) Air, sugar, oil
(c) Oxygen, water, sugar
(d) Salt, juice, air
(c) Oxygen, water, sugar

Question 6.
On converting 25°C, 38°C and 66°C to Kevlin scale, the correct sequence of temperature will be
(a) 298 K, 311 K and 339 K
(b) 298 K, 300 K and 338 K
(c) 273 K, 278 K and 543 K
(d) 298 K, 310 K and 338 K
(a) 298 K, 311 K and 339 K

Question 7.
Choose the correct statement from the following:
(a) Conversion of solid into vapour without passing through the liquid state is called vapourisation.
(b) Conversion of vapour into solid without passing through the liquid state is called sublimation.
(c) Conversion of vapour into solid without passing through the liquid state is called freezing.
(d) Conversion of solid into liquid is called sublimation.
(b) Conversion of vapour 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?
(a) 306 K, 329 K and 391 K
(b) 308 K, 329 K and 392 K
(c) 308 K, 329 K and 391 K
(d) 329 K, 392 K and 308 K
(c) 308 K, 329 K and 391 K

Question 9.
Which condition out of the following will increase the evaporation of water?
(a) Increase in temperature of water
(b) Decrease in temperature of water
(c) Less exposed surface area of water
(d) Adding common salt to water
(a) Increase in temperature of water

Question 10.
In which of the following conditions, the distance between the molecules of hydrogen gas would increase?
(i) Increasing pressure on hydrogen contained in a closed container
(ii) Some hydrogen gas leaking out of the container
(iii) Increasing the volume of the container of hydrogen gas
(iv) Adding more hydrogen gas to the container without increasing the volume of the container
(a) (i) and (iii)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (ii) and (iv)
(c) (ii) and (iii)

Question 11.
The boiling point of water at sea level is
(a) 0°C
(b) 273 K
(c) 373 K
(d) 273°C
(c) 373 K

Question 12.
Which of the following has the strongest interparticle forces at room temperature?
(a) Oxygen
(b) Water
(c) Bromine
(d) Iron
(d) Iron

Question 13.
Which of the following conditions is most favourable for converting a gas into a liquid?
(a) High pressure, low temperature
(b) Low pressure, low temperature
(c) Low pressure, high temperature
(d) High pressure, high temperature
(a) High pressure, low temperature

Question 14.
Dry ice is
(a) water in solid state
(b) water in gaseous state
(c) CO2 in liquid state
(d) CO2 in solid state
(d) CO2 in solid state

Complete the crossword given below:

Down:
1. Process of changing water to water vapour on heating.
2. Process of changing of a liquid into solid.
3. Physical state of water at 120°C.
Across:
4. Process of changing a solid directly to gaseous state.
5. Process of changing a solid into liquid.
6. Process of changing a gas into liquid on cooling.
7. SI unit of temperature.

Down:
1. Vapourisation
2. Solidification
3. Gas

Across:
4. Sublimation
5. Fusion
6. Condensation
7. Kelvin

Fill in the blanks:

1. Evaporation of a liquid at room temperature leads to a ………….. effect.