250+ TOP MCQs on Compressibility and Answers

Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) on “Compressibility”.

1. What is the compressibility of ideal gases?
a) 1
b) 2
c) 3
d) 4

Answer: a
Clarification: Compressibility = PV/nRT, but for ideal gases PV = nRT, => Compressibility = 1.

2. Which of the following is true about compressibility of real gases?
a) Z = 1
b) Z < 1
c) Z > 1
d) Both Z < 1 and Z > 1

Answer: d
Clarification: For any value of compressibility except 1, the gas is real.

3. What is the pressure of CO₂ gas with compressibility z = 0.8, if the ideal gas pressure of CO₂ is 10 Pa, all other variables are same?
a) 5
b) 8
c) 10
d) 14

Answer: b
Clarification: Pressure of CO₂ = 0.8*10 = 8 Pa.

4. What is the pressure of H₂ with compressibility 0.6, molar volume 5 liter/mole at 27^oC?
a) 2.9 atm
b) 5.4 atm
c) 9.6 atm
d) 14.5 atm

Answer: a
Clarification: P = znRT/V, => P = 0.6*0.0821*300/5 = 2.9 atm.

5. At what temperature, does SO₂ with compressibility 2 has pressure 5 atm and molar volume 10 mole/s?
a) 300.5 K
b) 304.5 K
c) 310 K
d) 312.5 K

Answer: b
Clarification: T = PV/zR = 5*10/(2*0.0821) = 304.5 K.

6. What is the compressibility factor of water with density 1 g/liter at 27^oC and 1 atm?
a) 0.25
b) 0.59
c) 0.73
d) 0.91

Answer: c
Clarification: z = PM/dRT = 1*18/(1*0.0821*300) = 0.73.

7. What is the compressibility factor of a liquid of molar mass 90 g and density 10 g/liter at 27^oC and 2 atm?
a) 0.14
b) 0.39
c) 0.51
d) 0.73

Answer: d
Clarification: z = PM/dRT = 2*90/(10*0.0821*300) = 0.73.

8. What is the pressure of 80 grams of CH₄ with compressibility 5, with 10 liter volume at 27^oC?
a) 10.5 atm
b) 28.9 atm
c) 44.2 atm
d) 61.5 atm

Answer: d
Clarification: P = 5*5*0.0821*300/10 = 61.5 atm.

9. What is the compressibility of methane with density 10 g/liter at 27^oC and 500 atm?
a) 32.5
b) 34.8
c) 39.6
d) 44.1

Answer: a
Clarification: z = PM/dRT = 500*16/(10*0.0821*300) = 32.5.

10. What is the compressibility of neon (molar mass = 20) with density 20 g/liter at 27^oC and 100 atm?
a) 2.1
b) 3.5
c) 4
d) 6.8

Answer: c
Clarification: z = PM/dRT = 100*20/(20*0.0821*300) = 4.

11. 90 g glucose is filled in a container at 10 atm, if the volume of container is 2 liter, what is the temperature of glucose (z = 1.5)?
a) 25.4^oC
b) 51.7^oC
c) 76.9^oC
d) 103.5^oC

Answer: b
Clarification: T = PV/znR = 10*2/(1.5*0.5*0.0821) = 324.8 K = 51.7^oC.

12. How many grams of C₂H₆ (z = 1.4) is present in the container at 27^oC and 5 atm and with volume 10 liter?
a) 20 g
b) 30.4 g
c) 40.6 g
d) 50.8 g

Answer: c
Clarification: n = 5*10/(1.4*0.0821*300) = 1.45, mass of C₂H₆ = 1.45*28 = 40.6 g.

13. What is the volume of 21 g of propane (z = 1.9) at 1 atm and 27^oC?
a) 23.4 liter
b) 37.5 liter
c) 42.1 liter
d) 59.6 liter

Answer: a
Clarification: V = 1.9*0.5*0.0821*300/1 = 23.4 liter.

14. 1 mole of cyclohexane (z = 1.2) is filled in a container at 27^oC and 4 atm, what is the volume of container?
a) 3.8 liter
b) 4.4 liter
c) 5.6 liter
d) 7.4 liter

Answer: d
Clarification: V = 1.2*1*0.0821*300/4 = 7.4 liter.

15. 39 grams of benzene (z = 1.4) is filled in a container of volume 10 liter at 27^oC, what is the pressure of container?
a) 1.7 atm
b) 1.9 atm
c) 2.2 atm
d) 2.5 atm

Answer: a
Clarification: P = 1.4*0.5*0.0821*300/10 = 1.7 atm.