Chemical Engineering

Material Balances Involving Ideal Gases

Question 1
Marks : +2 | -2
Pass Ratio : 100%
N2 with pressure 10 atm and H2 with pressure 30 atm, both with volume 10 liter at 27oC are passed into a reactor, how many moles NH3 is produced?
4
8
12
16
Explanation:
The reaction is N2 + 3H2 -> 2NH3, moles of N2 = 10*10/(0.0821*300) = 4, moles of H2 = 30*10/(0.0821*300) = 12, => extent of reaction = (0 – 4)/(-1) = 4, => moles of NH3 = 4*2 = 8.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
CO with pressure 10 atm at 27oC is passed through a reactor with O2, what is the pressure of CO2 produced if 60% CO reacted?
2 atm
6 atm
10 atm
14 atm
Explanation:
The reaction is 2CO + O2 -> 2CO2, pressure of CO2 = 10*0.6 = 6 atm.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
CH4 with pressure 10 atm and volume 5 liter at 27oC is passed into a reactor with 50% excess oxygen, how many moles of oxygen is left in the products?
2
4
6
8
Explanation:
The reaction is CH4 + 2O2 -> CO2 + 2H2O, moles of CH4 = 10*5/(0.0821*300) = 2, => moles of O2 left = 2*2(50/100) = 2.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
Glucose with pressure 10 atm at 27oC is passed through a reactor with O2, what is the temperature of CO2 produced if pressure becomes thrice?
150 K
240 K
300 K
330 K
Explanation:
The reaction is C6H12O6+ 9O2 -> 6CO2 + 6H2O, => 30/T = 6(10/300), => T = 150 K.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
H2 at 27oC with pressure 10 atm and volume 10 liter is passed through a reactor with 6 moles of oxygen, if the limiting reagent reacts completely, how many moles of oxygen is left unreacted?
1
2
4
6
Explanation:
The reaction is 2H2 + O2 -> 2H2O, moles of H2 passed = 10*10/(0.0821*300) = 4, => moles of H2 reacted = 4, => moles of O2 reacted = 4, => moles of O2 left unreacted = 6 – 2 = 4.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
A mixture with 60% O2 and 40% H2 with pressure 5 Pa at 27oC at the rate 15 liter/s is passed through a reactor with another stream containing pure H2 with pressure 10 Pa at 27oC at the rate 5 liter/s, what is the fraction of H2 with pressure 5 Pa at 27oC in product?
0.2
0.4
0.6
0.8
Explanation:
Overall material balance: 15 + 5 = P, => P = 20 mole/s, Overall O2 balance: 0.4*5*15 + 1*10*5 = 20*x*5, => x = 0.8.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
A gas mixture with 50% H2 at the rate F is passed through a reactor and it produced a gas mixture with 80% H2 at the rate 15 liter/s, what is the value of F?
5 liter/s
8 liter/s
15 liter/s
24 liter/s
Explanation:
Overall H2 balance: 0.5F = 0.8*15, => F = 24 liter/s.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
A gas mixture has 10% CH4 with pressure 5 Pa at 27oC at the rate F, is passed through a reactor with another stream containing 60% CH4 with pressure 5 Pa at -73oC at the rate 10 liter/s, if the percentage of CH4 with pressure 5 Pa at 27oC in product is 80%, what is the value of F?
1 liter/s
1.4 liter/s
2 liter/s
2.6 liter/s
Explanation:
Overall material balance: F + 10 = P, Overall CH4 Balance: 0.1*F*5/300 + 0.6*10*5/200 = 0.8*P*5/300, => F + 90 = 8P, => F = 10/7 = 1.4 liter/s.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
A gas mixture with 6% O2 with pressure 1 atm at 27oC is entered a reactor with rate F, and another stream with pure O2 with 2 atm pressure at 27oC entered the reactor with rate 1 liter/s, product has 10% O2 with same conditions with rate P, what is the value of F?
575.5 liter/s
725 liter/s
895 liter/s
997.5 liter/s
Explanation:
Overall material balance: F + 1 = P, O2 balance: 0.06*F + 2*1*1 = 0.1*P, => 6F + 400 = 10P, => F = 399*2.5= 997.5 liter/s.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
A gas mixture with 20% O2 with pressure 100 Pa at 27oC at the rate 50 liter/s is passed through a reactor and products a gas mixture with 40% O2 with pressure 25 Pa at 27oC, what is the rate of product?
50 liter/s
100 liter/s
200 liter/s
400 liter/s
Explanation:
O2 balance: 0.2*100*50 = 0.4*25*P, => P = 100 liter/s.