Chemical Engineering

Condensation

Question 1
Marks : +2 | -2
Pass Ratio : 100%
A process is carried out for the feed mixture of 95% air and 5% ammonia vapor, the compressor recovered 40% of ammonia, what is the exit pressure of the compressor, if the partial pressure of ammonia vapor is 10 mm Hg?
225.4 mm Hg
326.8 mm Hg
451.2 mm Hg
593.5 mm Hg
Explanation:
Exit components, ammonia: 0.05*0.6 = 0.03, air: 0.95, => yammonia = 0.03/0.98 = 0.0306, => Total exit pressure = 10/0.0306 = 326.8 mm Hg.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
If the fraction of water vapor at 27oC and 5 atm is 0.5, then what is the fraction of water vapor at 27oC and 1 atm?
0.1
0.2
0.5
0.8
Explanation:
Fraction of water vapor at 27oC and 1 atm = 0.5/5 = 0.1.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
A process is carried out for the feed mixture of 90% air and 10% water vapor, the compressor recovered 90% of water, what is the exit pressure of the compressor if the partial pressure of water vapor is 50 mm Hg?
286.1 mm Hg
396.4 mm Hg
458.7 mm Hg
529.5 mm Hg
Explanation:
Exit components, water: 0.1*0.1 = 0.01, air: 0.9, => water = 0.0109 => Total exit pressure = 50/0.109 = 458.7 mm Hg.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
Condensation starts at which point?
Dew point
Bubble point
Triple point
None of the mentioned
Explanation:
A dew point is a temperature at which condensation starts.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
A process is carried out for the feed mixture of 80% air and 20% CO2, the compressor recovered 50% of CO2, what is the exit pressure of the compressor, if the partial pressure of CO2 is 15 mm Hg?
135 mm Hg
145 mm Hg
175 mm Hg
200 mm Hg
Explanation:
Exit components, CO2: 0.2*0.5 = 0.1, air: 0.8, => yCO2 = 0.1/0.9 = 0.111, => Total exit pressure = 15/0.111 = 135 mm Hg.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
Which of the following defines condensation?
Change of solid to vapor
Change of vapor to liquid
Change of liquid to vapor
Change of vapor to solid
Explanation:
Condensation is phase change from vapor to liquid.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
What is the fraction of water vapor at 27oC and 1 atm, if the fraction of water vapor at 127oC and 1 atm is 0.8?
0.2
0.4
0.6
0.8
Explanation:
Fraction of water vapor at 127oC and 1 atm = 0.8*300/400 = 0.6.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is not a way of condensation of vapor?
Cooling at constant volume
Cooling at constant pressure
Compress it isothermally
Compress it
Explanation:
Compressing a gas and its temperature is increasing does not condense the vapor, compressing vapor at constant temperature is a way of condensation.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
A process is carried out for the feed mixture of 50% air and 50% methane vapor, the compressor recovered 20% of methane, what is the exit pressure of the compressor, if the partial pressure of methane vapor is 25 mm Hg?
56.3 mm Hg
78.9 mm Hg
92.1 mm Hg
98.7 mm Hg
Explanation:
Exit components, methane: 0.5*0.8 = 0.4, air: 0.5, => ymethane= 0.4/0.9 = 0.444, => Total exit pressure = 25/0.444 = 56.3 mm Hg.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
A process is carried out for the feed mixture of 40% air and 60% oxygen, the compressor recovered 2% of oxygen, what is the exit pressure of the compressor, if the partial pressure of oxygen vapor is 5 mm Hg?
2.4 mm Hg
4.8 mm Hg
6.5 mm Hg
8.4 mm Hg
Explanation:
Exit components, oxygen: 0.6*0.98 = 0.588, air: 0.4, => yoxygen= 0.588/0.988 = 0.595, => Total exit pressure = 5/0.595 = 8.4 mm Hg.