Matter in Our Surrounding | Extra Questions | Class 9

Fill in the blanks:-

1. Matter is made up of small_________.
2. The forces of attraction between the particles are _______ in solids, ______ in liquids and _________ in gases.
3. __________ is the change of gaseous state directly to solid state without going through liquid state, and vice-versa.
4. Evaporation causes __________.
5. Latent heat of fusion is the amount of heat energy required to change 1 kg of solid into liquid at its ________.
6. Solid, liquid and gas are called the three _______ of matter.
7. The smell of perfume gradually spreads across a room due to ______.
8. Rapid evaporation depends on the ______ area exposed to atmosphere.
9. As the temperature of a system increases, the pressure of the gases ______.
10. As the volume of a specific amount of gas decreases, it’s pressure _______.
11. As the temperature of a gas decreases, I’s volume ______.
12. Gas molecules at higher temperatures have more _______ than at cooler temperatures.
13. Usually the total charge of a plasma is _______.
14. The pressure inside of a sealed tube if you raise the temperature go ______
15. Forces of attraction in liquids are _______ than in olid.
16. Liquids that move quickly downhill are described as having _____.

Solution:

True/ False:-

1. Boiling is a bulk phenomenon.
2. Evaporation is a surface phenomenon.
3. The rate of evaporation depends only on the surface area exposed to the atmosphere.
4. Latent heat of vaporization is the heat energy required to change 1 kg. of a liquid to gas at atmospheric pressure at its melting point.
5. Water at room temperature is a liquid.
6. Atoms in a liquid are father apart than the atoms in a gas.
7. The molecules in a gas are in constant motion.
8. Gases present in air have the same pressure throughout the entire atmosphere.
9. All materials move from solid to liquid to gas as the temperature increases.
10. Because electrons have been stripped away from atoms in plasma, plasmas have a negative charge.
11. It is just as easy to compress a liquid, as it is to compress a gas.
12. Evaporation and boiling are the same processes because molecules move from a liquid to gaseous state.
13. If we pour liquid nitrogen into a glass, it will change its state to a solid.
14. You may find plasma in a star.
15. A system that changes from a solid state to a liquid state gains energy.
16. Plasmas are all made of the same ions. They have different colours due to different amounts of electricity.

Solutions:

 

Very Short Answer Questions-

1. Name the three states of matter. Give one example of each.
2. What are the two ways in which the physical state of matter can be changed?
3. Explain how gases can be liquefied?
4. What is sublimation? Give examples.
5. Define latent heat of fusion.
6. Define latent heat of vaporization.
7. What produces more severe burns, boiling water or steam?
8. How can the boiling point of a liquid be rased, without adding any impurity?
9. In how many forms did the earlier scientists classify matter?
10. Why does a summer rainstorm lower the temperature?
11. A beaker of a liquid with a vapour pressure of 350 torr at 25°C is set alongside a beaker of water (Vapour pressure of 23.76 torr) and both are allowed to evaporate. In which liquid does the temperature change at a faster rate? Why
12. At a given temperature, one liquid has a vapour pressure of 240 torr and another measure 420 torr. Which liquid probably has the lower boiling point? Which probably has the lower heat of vaporization?
13. A drop of dettol got evenly distributed in water. How?
14. Liquid nitrogen is used as a commercial refrigerant to flash freeze foods. Nitrogen boils at -196°C. What is this temperature on the Kelvin temperature scale?
15. What property or properties of gases can you point to support the assumption that most of the volume in a gas is empty space?
16. What is unit cell?
17. What is the effect on surface tension of temperature?
18. Surface tension is same for different liquids. Explain.

19.  What is condensation? How is the condensation of a gas carried out?

Short Answer Questions-

1. Why do solids not diffuse?

2. Convert the following Kelvin temperature to degrees Celsius.

  1. 175 K
  2. 295 K
  3. 300 K
  4. 225 K

 

3 Convert the following Celsius temperature to Kelvin temperature.

  1. 250C
  2. -150C
  3. 00C
  4. 30C

 

4. Arrange the following substances in increasing order of intermolecular force of attraction:

water, sugar, oxygen

5.  What is the physical state of water at the following temperatures?

(a) 250C

(b) 00C

(c) 1000C

6. Why does the temperature of a substance remain constant during melting and boiling even when heat is being supplied to it continuously?

7. Explain the diffusion of copper sulphate into water.

8. Why do the gases exert more pressure on the walls of the container than the solids?

9. The process in which a solid is converted directly into a gas is called sublimation. Iodine is an element that sublimes. A sample of solid iodine in a stoppered flask was allowed to stand undisturbed for several days. Crystals of solid iodine grew on the sides of the flask. Explain at the molecular level what happened?

10. Give three examples of crystalline and amorphous solids.

12. Describe why a drop of food coloring in a glass of water slowly becomes evenly distributed without the need for stirring?

13. Liquid mix more slowly than gases. Why?

14. Define the following terms:

  1. Melting point
  2. Freezing point
  3. Boiling point

15. A constant pressure tank of gas at 1.01 Atm has propane in it at 150C when it is at 255 cubic meters. What is its volume at 480C?

16. What is the mass of 15 liters of chlorine gas at STP?

17. How many liters of hydrogen at 00C and 1400mm of Hg are produced if 15g of magnesium reacts with sulphuric acid?

Test (Matter in Our Surroundings)

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