Basic Chemical Engineering Questions and Answers Part-9

1. Which of the following is not the unit of concentration?
a) Mole/m3
b) Molar
c) N/m3
d) ppm

Answer: c
Explanation: Concentration is moles per unit volume or mass per unit volume, so N/m3 cannot be a unit of concentration.

2. What is the concentration of a 22 grams of carbon dioxide occupying 0.5 m3 volume?
a) 1 mole/m3
b) 2 mole/m3
c) 11 mole/m3
d) 22 mole/m3

Answer: a
Explanation: Moles of carbon dioxide = 22/44 = 0.5, => concentration = 0.5/0.5 = 1 mole/m3.

3. What is the concentration of 100 lbs. of solution occupying 25 m3 of volume?
a) 1.8 Kg/m3
b) 2.7 Kg/m3
c) 4 Kg/m3
d) 8 Kg/m3

Answer: a
Explanation: Mass of solution = 100*0.453 = 45.3 kg, => Concentration of solution = 45.3/25 = 1.8 kg/m3.

4. What is the molarity of a solution with a mass of solute 10 kg mass and 100 liter volume?
a) 0.1 molar
b) 1 molar
c) 10 molar
d) 100 molar

Answer: a
Explanation: Molarity = 10/100 = 0.1 molar.

5. What is the concentration of a solution with 10 grams of calcium in 1000 m3 of water?
a) 150 ppm
b) 250 ppm
c) 800 ppm
d) 1000 ppm

Answer: b
Explanation: Moles of calcium = 10/40 =0.25, => concentration in ppm = (0.25/1000)*106 = 250 ppm.

6. Which of the following is not a unit of temperature?
a) Celsius
b) Fahrenheit
c) Therm
d) Rankine

Answer: c
Explanation: Them is a unit of energy, 1 therm = 105 BTU.

7. Which of the following is greatest?
a) 10oC
b) 10oR
c) 10oF
d) 10 K

Answer: a
Explanation: 10oC = 283 K = 50oF = 510oR, => 10oC is greatest.

8. Absolute zero temperature is approximately equal to?
a) -160oR
b) -273oR
c) -373oR
d) -460oR

Answer: d
Explanation: Absolute zero temperature = 0 K = -273oC = -460oR.

9. If change in temperate is 212 degree Fahrenheit, what is the change in temperature in degree Rankine?
a) 100oR
b) 212oR
c) 273oR
d) 460oR

Answer: b
Explanation: Since ∆TR = ∆TF, => 212oF = 212oR.

10. If change in temperate is 180 degree Rankine, what is the change in temperature in degree Celsius?
a) 100oC
b) 180oC
c) 212oC
d) 273oC

Answer: a
Explanation: ∆TR = 1.8∆TC, => Change in temperature = 180/1.8 = 100oC.