CBSE Class 11 The Gaseous State and The Gas Laws Worksheet A

Question. The kinetic theory of gases perdicts that total kinetic energy of a gaseous assembly depends on
a. Pressure of the gas
b. Temperature of the gas
c. Volume of the gas
d. Pressure, volume and temperature of the gas
Answer : B

Question. The density of neon will be highest at:
a. S.T.P.
b. 0°C, 2 atm
c. 273°C, 1 atm
d. 273°C, 2 atm
Answer : B

Question. Indicate the correct statement for a 1-L sample of N₂ (g) and CO₂ (g) at 298 K and 1 atm pressure
a. The average translational KE per molecule is the same in N₂ and CO₂
b. The rms speed remains constant for both N2 and CO₂
c. The density of N₂ is less than that of CO₂
d. The total translational KE of both N₂ and CO₂ is the same Pressure of an Ideal Gas
Answer : A, C, D

Question. If the inversion temperature of a gas is –80°C, then it will produce cooling under Joule-Thomson effect at
a. 298 K
b. 273 K
c. 193 K
d. 173 K
Answer : D

Question. Ratio of C_P and C_v of a gas 'X' is 1.4. The number of atoms of the gas 'X' present in 11.2 litres of it at N.T.P. is
a. 6.02×10²³
b. 1.2×10²⁴
c. 3.01×10²³
d. 2.01×10²³
Answer : A

Question. A gas at a certain volume and temperature has pressure 75 cm. If the mass of the gas is doubled at the same volume and temperature, its new pressure is:
a. 37.5 cm
b. 75 cm
c. 150 cm
d. 300 cm
Answer : C

Question. The ratio of root mean square velocity to average velocity of gas molecules at a particular temperature is
a. 1.086 : 1
b. 1 : 1.086
c. 2 : 1.086
d. 1.086 : 2
Answer : A

Question. At room temperature, the rms speed of the molecules of certain diatomic gas is found to be 1930 m/s. The gas is:
a. H₂
b. F₂
c. O₂
d. Cl₂
Answer : A

Question. According to kinetic theory of gases, for a diatomic molecule
a. The pressure exerted by the gas is proportional to the mean velocity of the molecules
b. The pressure exerted by the gas is proportional to the root mean square velocity of the molecules
c. The root mean square velocity is inversely proportional to the temperature
d. The mean translational kinetic energy of the molecules is proportional to the absolute temperature
Answer : D

Question. The density of air is 0.00130 g/ml. The vapour density of air will be:
a. 0.00065
b. 0.65
c. 14.4816
d. 14.56
Answer : D

Question. A cylinder of capacity 20 litres is filled with H₂ gas. The total average kinetic energy of translatory motion of its molecules is 1.5×10⁵ J . The pressure of hydrogen in the cylinder is:
a. 2×10⁶ N /m²
b. 3×10⁶ N /m²
c. 4×10⁶ N /m²
d. 5×10⁶ N /m²
Answer : D

Question. The molecules of a given mass of a gas have a rms velocity of 200 m/sec at 27°C and 1.0 x 10⁵ N /m² pressure. When the temperature is 127°C and pressure is 0.5×10⁵ N /m² , the rms velocity in m/sec will be:
a. 100 √2/3
b. 100 √2
c. 400/√3
d. None of these
Answer : C

Question. A vessel contains a mixture of one mole of oxygen and two moles of nitrogen at 300 K. The ratio of the average rotational kinetic energy per O₂ molecule to that per N₂ molecule is:
a. 1 : 1
b. 1 : 2
c. 2 : 1
d. Depends on the moments of inertia of the two molecules
Answer : A

Question. Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will:
a. Increase
b. Decrease
c. Remain same
d. Decrease for some, while increase for others
Answer : C

Question. The speeds of 5 molecules of a gas (in arbitrary units) are as follows: 2, 3, 4, 5, 6. The root mean square speed for these molecules is:
a. 2.91
b. 3.52
c. 4.00
d. 4.24
Answer : D

Question. The average translational energy and the rms speed of molecules in a sample of oxygen gas at 300 K are 6.21 x 10^-21 J and 484 m/s respectively. The corresponding values at 600 K are nearly: (assuming ideal gas behaviour)
a. 12.42 10^-21 J,968m/ s
b. 8.78 10^-21 J ,684m/ s 
c. 6.21 10^-21 J,968m/ s 
d. 12.42 10^-21 J,684m/ s
Answer : D

Question. A balloon contains 500 m³ of helium at 27°C and 1 atmosphere pressure. The volume of the helium at – 3°C temperature and 0.5 atmosphere pressure will be:
a. 500 m³
b. 700 m³
c. 900 m³
d. 1000 m³
Answer : C

Question. Which of the following statement is true?
a. Absolute zero degree temperature is not zero energy temperature
b. Two different gases at the same temperature pressure have equal root mean square velocities
c. The rms speed of the molecules of different ideal gases, maintained at the same temperature are the same
d. Given sample of 1cc of hydrogen and 1cc of oxygen both at N.T.P. oxygen sample has a large number of molecules
Answer : A

Question. A flask contains 10^–3 m³ gas. At a temperature, the number of molecules of oxygen are 3.0×10²² . The mass of an oxygen molecule is 5.3x10⁻²⁶ kg and at that temperature the rms velocity of molecules is 400 m/s. The pressure in N / m² of the gas in the flask is:
a. 8.48×10⁴
b. 2.87×10⁴
c. 25.44×10⁴
d. 12.72×10⁴
Answer : A

Question. At what temperature is the root mean square velocity of gaseous hydrogen molecules is equal to that of oxygen molecules at 47°C:
a. 20 K
b. 80 K
c. – 73 K
d. 3 K
Answer : A

Question. Gas at a pressure P0 in contained as a vessel. If the masses of all the molecules are halved and their speeds are doubled, the resulting pressure P will be equal to:
a. 4P₀
b. 2P₀
c. P₀
d. P₀/ 2
Answer : B

Question. At what temperature the RMS velocity of SO₂ be same as that of O₂ at 303 K:
a. 273 K
b. 606 K
c. 303 K
d. 403 K
Answer : B

Question. The r.m.s. velocity of a certain gas is v at 300 K . The temperature, at which the r.m.s. velocity becomes double:
a. 1200 K
b. 900 K
c. 600 K
d. 150 K
Answer : A

Question. A gas in container A is in thermal equilibrium with another gas in container B. both contain equal masses of the two gases in the respective containers. Which of the following can be true?
a. P_A V_A = P_B V_B
b. P_A = P_B ,V_A ≠ V_B
c. P_A ≠ P_B ,V_A = V_B
d. P_A/V_A = P_BV_B
Answer : B, C

Question. At constant temperature on increasing the pressure of a gas by 5% will decrease its volume by:
a. 5%
b. 5.26%
c. 4.26%
d. 4.76%
Answer : D

Question. Air is filled at 60°C in a vessel of open mouth. The vessel is heated to a temperature T so that 1 / 4^th part of air escapes. Assuming the volume of vessel remaining constant, the value of T is:
a. 80°C
b. 444°C
c. 333°C
d. 171°C
Answer : D

Question. The expansion of an ideal gas of mass m at a constant pressure P is given by the straight line D. Then the expansion of the same ideal gas of mass 2m at a pressure P/ 2 is given by the straight line

a. E
b. C
c. B
d. A
Answer : D

Question. A perfect gas at 27°C is heated at constant pressure to 327°C. If original volume of gas at 27°C is V then volume
at 327°C is:
a. V b. 3V
c. 2V
d. V/2
Answer : C

Question. Two gases occupy two containers A and B the gas in A, of volume 0.10 m³, exerts a pressure of 1.40 MPa and that in B of volume 0.15 m³ exerts a pressure 0.7 MPa. The two containers are united by a tube of negligible volume and the gases are allowed to intermingle. Then it the temperature remains constant, the final pressure in the container will be: (in MPa)
a. 0.70
b. 0.98
c. 1.40
d. 2.10
Answer : B

Question. The average kinetic energy per molecule of helium gas at temperature T is E and the molar gas constant is R, then Avogadro’s number is:
a. RT/2E
b. 3RT/E
c. E/2RT
d. 3RT/2E
Answer : D

Question. On 0°C pressure measured by barometer is 760 mm. What will be pressure on 100°C?
a. 760 mm
b. 730 mm
c. 780 mm
d. None of these
Answer : D

Question. The ratio of rms speeds of the gases in the mixture of nitrogen oxygen will be:
a. 1 : 1
b. √3 : 1
c. √8 : √7
d. √6 : √7
Answer : C

Question. At which of the following temperature would the molecules of a gas have twice the average kinetic energy they have at 20°C:
a. 40°C
b. 80°C
c. 313°C
d. 586°C
Answer : C

Question. A flask is filled with 13 gm of an ideal gas at 27°C and its temperature is raised to 52°C. The mass of the gas that has to be released to maintain the temperature of the gas in the flask at 52°C and the pressure remaining the same is:
a. 2.5 g
b. 2.0 g
c. 1.5 g
d. 1.0 g
Answer : D

Question. If the value of molar gas constant is 8.3 J/mole-K, the n specific gas constant for hydrogen in J/mole-K will be:
a. 4.15
b. 8.3
c. 16.6
d. None of these
Answer : A

Question. A box containing N molecules of a perfect gas at temperature T₁ and pressure P₁. The number of molecules in the box is doubled keeping the total kinetic energy of the gas same as before. If the new pressure is P₂ and temperature T₂, then:
a. P₂ = P₁ , T₂ = T₁
b. P₂ = P₁ , T₂ = T₁/2
c. P₂ = 2P₁ , T₂ = T₁
d. P₂ = 2P₁ , T₁ = T₁/2
Answer : B

Question. A gas at 27°C has a volume V and pressure P. On heating its pressure is doubled and volume becomes three times.
The resulting temperature of the gas will be:
a. 1800°C
b. 162°C
c. 1527°C
d. 600°C
Answer : C

Question. If pressure of a gas contained in a closed vessel is increased by 0.4% when heated by 1°C, the initial temperature must be:
a. 250 K
b. 250°C
c. 2500 K
d. 25°C
Answer : A

Question. Under which of the following conditions is the law PV = RT obeyed most closely by a real gas:

a. High pressure and high temperature
b. Low pressure and low temperature
c. Low pressure and high temperature
d. High pressure and low temperature
Answer : C

Question. Hydrogen gas is filled in a balloon at 20°C. If temperature is made 40°C, pressure remaining same, what fraction of hydrogen will come out?
a. 0.07
b. 0.25
c. 0.5
d. 0.75
Answer : A

Question. The capacity of a vessel is 3 litres. It contains 6 gm oxygen, 8 gm nitrogen and 5 gm CO₂ mixture at 27°C. If R = 8.31 J/mole × kelvin, then the pressure in the vessel in N/m² will be: (approx.)
a. 5×10⁵
b. 5×10⁴
c. 106
d. 105
Answer : A

Question. At standard temperature and pressure the density of a gas is 1.3 gm/ m³ and the speed of the sound in gas is 330 m/sec. Then the degree of freedom of the gas will be:
a. 3
b. 4
c. 5
d. 6
Answer : C

Question. A closed vessel contains 8g of oxygen and 7g of nitrogen. The total pressure is 10 atm at a given temperature. If now oxygen is absorbed by introducing a suitable absorbent the pressure of the remaining gas in atm will be:
a. 2
b. 10
c. 4
d. 5
Answer : D

Question. Temperature of an ideal gas is T K and average kinetic energy is E = 2.07x10⁻²³ T Joule/molecule. Number of molecules in 1 litre gas at S.T.P. will be:
a.2.68×10²²
b. 2.68×10²⁵
c. 2.68×10²⁸
d. 1.68×10²²
Answer : A

Question. If the mean free path of atoms is doubled then the pressure of gas will become:
a. P/4
b. P/2
c. P/8
d. P
Answer : B

Question. For a gas the difference between the two specific heats is 4150 J/kg K. What is the specific heats at constant volume of gas if the ratio of specific heat is 1.4:
a. 8475 J/kg - K
b. 5186 J/kg - K
c. 1660 J/kg - K
d. 10375 J/kg - K
Answer : D

Question. The equation of state of a gas is given by (P + aT²/V)V^c= = (RT + b) , where a, b, c and R are constants. The isotherms can be represented by P = AV^m − BVⁿ , where A and B depend only on temperature then:
a. m = −c and n = −1
b. m = c and n =1
c. m = −c and n =1
d. m = c and n = −1
Answer : A

Question. Energy of all molecules of a monoatomic gas having a volume V and pressure P is (3/2)PV . The total translational kinetic energy of all molecules of a diatomic gas as the same volume and pressure is:
a. (1/2)PV
b. (3/2)PV
c. (5/2)PV
d. 3 PV
Answer : B

Question. Two cylinders A and B fitted with pistons contain equal amounts of an ideal diatomic gas at 300K. The piston of A is free to move while that of B is held fixed. The same amount of heat is given to the gas in each cylinder. If the rise in temperature of the gas in A is 30 K, then the rise in temperature of the gas in B is :
a. 30
K b. 18 K
c. 50 K
d. 42 K
Answer : D

Question. A monoatomic gas expands at constant pressure on heating. The percentage of heat supplied that increases the internal energy of the gas and that is involved in the expansion is:
a. 75%, 25%
b. 25%, 75%
c. 60%, 40%
d. 40%, 60%
Answer : C

Question. The mean free path of nitrogen molecules at a pressure of 1.0 atm and temperature 0°C is 0.8x10 m⁻⁷ . If the number of density of molecules is 2.7×10²⁵ perm³ , then the molecular diameter is:
a. 3.2 nm
b. 3.2 Å
c. 3.2μm
d. 2.3mm
Answer : B

Question. Find the ratio of specific heat at constant pressure to the specific heat constant volume for NH₃ :
a. 1.33
b. 1.44
c. 1.28
d. 1.67
Answer : C

Question. For a gas R/C_v = 0.67 This gas is made up of molecules which are:
a. Diatomic
b. Mixture of diatomic and polyatomic molecules
c. Monoatomic
d. Polyatomic
Answer : C

Question. The density of a polyatomic gas is standard conditions is 0.795 kgm⁻³ . The specific heat of the gas at constant volume is:
a. 1 1 930 J-kg⁻¹ K⁻¹
b. 1 1 1400 J- kg⁻¹ K⁻¹
c. 1 1 1120 J- kg⁻¹ K⁻¹
d. 1 1 925 J- kg⁻¹ K⁻¹
Answer : B

Question. The specific heat of a gas:
a. Has only two values of C_p and C_v
b. Has a unique value at a given temperature
c. Can have any value between 0 and ∞
d. Depends upon the mass of the gas
Answer : C

Question. The temperature of 5 mole of a gas which was held at constant volume was changed from 100^oC to 120^oC. The change in internal energy was found to be 80 J. The total heat capacity of the gas at constant volume will be equal to:
a. 1 8 J K⁻¹
b. 1 0.8 J K⁻¹
c. 1 4 J K⁻¹
d. 1 0.4 J K⁻¹
Answer : C

Question. A gas, is heated at constant pressure. The fraction of heat supplied used for external work is:

Answer : B

Question. If two moles of diatomic gas and one mole of monoatomic gas are mixed with then the ratio of specific heats is:
a. 7/3
b. 5/4
c. 19/13
d.15/19
Answer : C

1. Define Boyle’s law.

2. Why helium and hydrogen gases not liquefied at room temperature by applying very high pressure?

3. At what temperature will the volume of a gas at 0° c double itself, pressure remaining constant?

4. How is the pressure of a given sample of a gas related to temperature at volume?

5. Define absolute zero temperature.

6. 50 cm³ of hydrogen gas enclosed in a vessel maintained under a pressure of 1400 Torr, is allowed to expand to 125 cm³ under constant temperature conditions. What would be its pressure?

7. State the law depicting the volume-temperature relationship. 

8. State Avogadro’s Law. Is the converse of Avogadro’s law true? 

Click on link below to download CBSE Class 11 The Gaseous State and The Gas Laws Worksheet A.