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3.GASES eLearn.Punjab

Excercise

Q 1: Select the correct answer out of the following alternative suggestions.
(i) Pressure remaining constant, at which temperature the volume of a gas will become twice of what it is
at 0°C.

a. 546°C b. 200°C c. 546K d. 273K
(ii) Number of molecules in one dm3 of water is close to

a. 6.02 x 1023 b. 12.04 x 1023 c. 18 x 1023 d. 55.6 x 6.02 x 1023
22.4 22.4 22.4

(iii) Which of the following will have the same number of molecules at STP?

a. 280 cm3 of CO2 and 280 cm3 of N2O
b. 11.2 dm3 of O2 and 32 g of O2
c. 44 g of CO2 and 11.2 dm3 of CO
d. 28 g of N2 and 5.6 dm3 of oxygen
(iv) If absolute temperature of a gas is doubled and the pressure is reduced to one half, the volume of the

gas will

a. remain unchanged b. increase four times

c. reduce to 1/4 d. be doubled

(v) How should the conditions be changed to prevent the volume of a given gas from expanding

when its mass is increased?

a. Temperature is lowered and pressure is increased.

b. Temperature is increased and pressure is lowered.

c. Temperature and pressure both are lowered.

d. Temperature and pressure both are increased.

(vi) The molar volume of CO2 is maximum at c. 0°C and 2 atm d. 273°C and 2 atm
a. S TP b. 127°C and 1 atm

(vii) The order of the rate of diffusion of gases NH3, SO2, Cl2, an CO2 is:

a. NH3 > SO2 > Cl2 > CO2 b. NH3 > CO2 > SO2 > Cl2

c. Cl2 > SO2 > CO2 > NH3 d. NH3 > CO2 > Cl2 > SO2

(viii) Equal masses of methane and oxygen are mixed in an empty container at 25°C. The fraction

of total pressure exerted by oxygen is

a. 1/3 b. 8/9 c. 1/9 d. 16/17

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