Class 9 Science CBSE Long Answer type questions for matter in our Surroundings

Given below are the Class 9 Science CBSE Long Answer type questions for matter in our Surroundings
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Question 1. Explain why?
i. A gas fill a vessel completely.
ii. Camphor disappears without leaving any residue.
iii. The temperature does not rise during the process of melting and boiling, through heat energy is constantly supplied.
iv. Water stored in an earthen vessel becomes cool.
v. An iron almirah is a solid at room temperature.

Question 2. Which phenomenon occurs during the following changes?
ii. Wax melts in the sun.
iii. Drying of wet clothes
iv. Formation of clouds
v. Density of liquids is more than gases.

Question 3. Calculate each of the following quantities for an ideal gas
a) The volume of the gas in liters, if 2.46 mol has a pressure of 1.28 atm at a temperature of -60C;
b) The absolute temperature of the gas at which 4.79 x 10-2 mol occupies 135 mL at 720 torr;
c) The pressure, in atmospheres, if 5.52 x 10-2 mol occupies 413 mL at 880C;
d) The quantity of gas, in moles, if 88.4 L at 540C has a pressure of 9.84 kPa.

Question 4. Vessel A contains CO(g) at 00C and 1 atm. Vessel B contains SO2 (g) at 200C and 0.5 atm. The two vessels have the same volume.
a) Which contains more molecules?
b) Which contains more mass?
c) In which vessel is the average kinetic energy of molecules higher?

Question 5. Define:
i. Melting point
ii. Boiling point
iii. Vapourisation
iv. Freezing
v. Brownian motion
Question 6.. Differentiate between amorphous and crystalline solids.

Question 7.Match the following

Question 8.Arrange the state in increasing order of the forces of attraction between the particles
b) Gas
c) Solid

Question 9.What is Plasma and Bose-Einstein Condensate
Question 10. On converting 25C, 38C and 66C to kelvin 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

Question 11. A glass tumbler containing hot water is kept in the freezer compartment of a refrigerator (temperature < 0C). If you could measure the temperature of the content of the tumbler, which of the following graphs would correctly represent the change in its temperature as a function of time.

Question 12. A student heats a beaker containing ice and water. He measures the temperature of the content of the beaker as a function of time. Which of the following would correctly represent the result? Justify your choice.

Question 13.Why does the temperature of a substance remain constant during its melting point or boiling point?

Question 14.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)


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