Chemical Process Calculation Multiple Choice Questions & Answers (MCQs) focuses on “Element Material Balances”.
1-3. For the given hydro-cracking problem, mole percent of products C4H10, C3H8 and C2H6 are 20.2%, 58.4% and 21.4% respectively.
1. What is the mole percent of C6H14 in the feed?
a) 40.2
b) 50.2
c) 60.2
d) 70.2
Answer: c
Clarification: Element material balance for each element.
2. What is the mole percent of H2 in the feed?
a) 59.2
b) 49.2
c) 39.2
d) 29.9
Answer: b
Clarification: Element material balance for each element.
3. Molar ratio of H2 consumed to Hexane reacted in the process?
a) 1.2
b) 1.4
c) 1.6
d) 1.8
Answer: a
Clarification: Element material balance for each element.
4-6. For producing 40 % Methane, 20% Ethane and 40% Butane, a reactor is feed with Pentane and Hydrogen.
4. What is the mole fraction of Hydrogen in the feed?
a) 0.284
b) 0.484
c) 0.684
d) 0.884
Answer: c
Clarification: Element material balance for each element.
5. What is the mole fraction of Pentane in the feed?
a) 0.315
b) 0.215
c) 0.115
d) None of the mentioned
Answer: a
Clarification: Element material balance for each element.
6. What is the ratio of Hydrogen to the Pentane in the feed?
a) 1.167
b) 2.167
c) 3.167
d) 4.167
Answer: b
Clarification: Ratio = 104/48 = 2.167.
7-10. C3H8 is burned in air with a composition of 40 moles and 100 moles.
7. What is the number of moles of CO2 in the product?
a) 12.6
b) 10.6
c) 8.6
d) 4.6
Answer: a
Clarification: Moles of CO2 = Extent of the reaction*3.
8. What is the number of moles of H2O in the product?
a) 4.8
b) 8.8
c) 16.8
d) 32.8
Answer: c
Clarification: Moles of H2O = Extent of the reaction*2.
9. What is the number of moles of C3H8 in the product?
a) 25.8
b) 35.8
c) 45.8
d) 55.8
Answer: b
Clarification: Moles of C3H8 = 40-Extent of the reaction.
10. How many moles of O2 are required for the complete combustion of C3H8?
a) 160.48
b) 170.48
c) 180.48
d) 190.48
Answer: d
Clarification: Suppose x moles are required then 0.21x = 48.