Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) on “Ideal Gas Law”.
1. Which of the following term does not involve in ideal gas law?
a) Pressure
b) Volume
c) Temperature
d) Time
Answer: d
Clarification: Ideal gas law is PV = nRT, which does not involve time.
2. What is the shape of a P-T curve for ideal gas?
a) Straight line
b) Parabolic
c) Hyperbolic
d) Ellipse
Answer: a
Clarification: P-T curve is a straight line for ideal gas.
3. What is the shape of a V-T curve for ideal gas?
a) Straight line
b) Parabolic
c) Hyperbolic
d) Ellipse
Answer: a
Clarification: V-T curve is straight line for ideal gas.
4. What is the shape of a P-V curve for an ideal gas?
a) Straight line
b) Parabolic
c) Hyperbolic
d) Ellipse
Answer: c
Clarification: P-V curve is hyperbolic for an ideal gas.
5. Which of the following is not true about ideal gas molecules?
a) They have negligible size
b) They do not have attractive forces
c) They do not apply pressure
d) They move in random motion
Answer: c
Clarification: Ideal gas molecules apply pressure to the walls of a container.
6. What is the pressure of a 5 liter/mole ideal gas at temperature 27oC?
a) 2.5 atm
b) 3.8 atm
c) 4.4 atm
d) 5.3 atm
Answer: d
Clarification: PV = nRT, => P*5 = 0.0821*300, => P = 5.3 atm.
7. What is the Temperature of a 2 liter/mole ideal gas with pressure 10 atm?
a) 243.6 K
b) 268.4 K
c) 289.1 K
d) 313.5 K
Answer: a
Clarification: PV = nRT, => 10*2 = 0.0821*T, => T = 243.6 K.
8. First of the two ideal gases has twice molar volume as much as the second at same temperature, what is the ratio of their pressures?
a) 4:1
b) 1:4
c) 2:1
d) 1:2
Answer: d
Clarification: P1V1 = n1RT1, P2V2 = n2RT2 dividing both the equations, => P1😛2 = 1:2.
9. 88 grams of CO2 at 27oC is applying 5 atm pressure, what is the volume occupied by it?
a) 5.6 liter
b) 7.9 liter
c) 9.8 liter
d) 12.2 liter
Answer: c
Clarification: n = 88/44 = 2, PV = nRT, => 5*V = 2*0.0821*300, => V = 9.8 liter.
10. What is the density of O2 at 27oC with pressure 1 atm?
a) 1.1 g/L
b) 1.3 g/L
c) 1.5 g/L
d) 1.7 g/L
Answer: b
Clarification: Molecular wt. of O2= 44 g, PV = nRT, => PV = (m/M)RT, => d = PM/RT = (1*32)/(0.0821*300) = 1.3 g/L.
11. What is the molecular mass of an ideal gas with pressure 1 atm, and density 10 g/L at temperature 27oC?
a) 84.5 g
b) 135.1 g
c) 186.8 g
d) 246.3 g
Answer: d
Clarification: M = dRT/P = 10*0.0821*300/1 = 246.3 g.
12. What is the specific gravity of CO2 at 27oC and pressure 1 atm with respect to air of with density 1 g/L?
a) 1.23
b) 1.55
c) 1.78
d) 1.96
Answer: c
Clarification: Density of CO2 = PM/RT = 1*44/(0.0821*300) = 1.78 g/L, => Specific gravity = 1.78/1 = 1.78.
13. What is the specific gravity of CO at 27oC and pressure 5 atm with respect to air (molecular wt. = 29 g) at 27oC and pressure 10 atm?
a) 0.48
b) 0.56
c) 0.64
d) 0.72
Answer: a
Clarification: Density of CO = 5*28/(0.0821*300) = 5.68 g/L, density of air = 10*29/(0.0821*300) = 11.77 g/L, => specific gravity = 5.68/11.77 = 0.48.
14. What is the compressibility factor for an ideal gas?
a) 1
b) 2
c) 3
d) Depends on the gas
Answer: a
Clarification: Compressibility of an ideal gas is always 1.
15. Which of the following is not the unit of R?
a) Atm.liter/K.mole
b) Pa.m3/K
c) N.Kg.m3/K.mole
d) None of the mentioned
Answer: c
Clarification: N.Kg.m/K.mole is the unit of R.