103 + Interview Questions in The Chemical Reaction Equation & Stoichometry in Basic Chemical Engineering Page 1 InterviewSolution

1.	How many independent equation are possible if 1 has pure A, 2 has mixture of B and C, 3 has mixture of A, B and C, 4 has pure C, 5 has mixture of A and B.(a) 1(b) 3(c) 6(d) 9I got this question in an internship interview.My question is based upon Material Balances Problems Involving Multiple Units in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Correct choice is (C) 6 To elaborate: It will be just THRICE the NUMBER when there was only ONE component.

Discussion

2.	How many independent equations are possible if each stream contains mixture of A, B and C?(a) 1(b) 3(c) 6(d) 8I had been asked this question in a national level competition.The query is from Material Balances Problems Involving Multiple Units in chapter The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Correct option is (C) 6 For explanation: It will be just THRICE the NUMBER when there was only one component.

Discussion

3.	1 has pure A and 2 has pure B and 3, 4 and 5 has mixture of A and B, how many independent equations are possible?(a) 1(b) 2(c) 3(d) 4I had been asked this question during a job interview.This intriguing question comes from Material Balances Problems Involving Multiple Units in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Correct choice is (d) 4 The EXPLANATION is: It will be just TWICE the number when there is only ONE COMPONENT.

Discussion

4.	How many independent equations are possible, if two components are involved in each of streams?(a) 1(b) 2(c) 3(d) 4This question was posed to me by my school principal while I was bunking the class.My question comes from Material Balances Problems Involving Multiple Units topic in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Correct OPTION is (d) 4 Easiest explanation: It will be just the double of the number of independent EQUATIONS if there was only one component.

Discussion

5.	How many independent equations are possible, if only one component exists in each stream?(a) 1(b) 2(c) 3(d) 4I have been asked this question during an online exam.Query is from Material Balances Problems Involving Multiple Units topic in portion The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The correct ANSWER is (b) 2 To elaborate: For whole PROCESS: 1 + 2 = 4 + 5, for first REACTOR: 1 + 2 = 3, for second reactor: 3 = 4 + 5, but if we equate second and third equation we get the first one, so there are 2 independent equations.

Discussion

6.	What is the value of F?(a) 98.5 Kg/hr(b) 131.1 Kg/hr(c) 167.7 Kg/hr(d) 256.4 Kg/hrThis question was addressed to me in a job interview.The question is from Material Balances Problems Involving Multiple Units in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Right answer is (c) 167.7 Kg/hr The best I can explain: Material balance for ETHANOL: 2000.2 = F0.05 + D0.98, => 5F + 98D = 4000, material balance for water: 2000.8 = F0.95 + D0.02, => 95F + 2D = 16000, Solving both equations we get F = 167.7 Kg/hr.

Discussion

7.	What is the value of W?(a) 159.2 Kg/hr(b) 281.3 Kg/hr(c) 465.7 Kg/hr(d) 633.8 Kg/hrI have been asked this question in semester exam.This question is from Material Balances Problems Involving Multiple Units in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» RIGHT ANSWER is (a) 159.2 Kg/hr The EXPLANATION: A + W = B + C, => 1000 + W = 200 + 959.2, => W = 159.2 Kg/hr.

Discussion

8.	What is the value of C?(a) 400 Kg/hr(b) 689.5 Kg/hr(c) 819.6 Kg/hr(d) 959.2 Kg/hrThe question was posed to me in a national level competition.This interesting question is from Material Balances Problems Involving Multiple Units topic in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The CORRECT OPTION is (d) 959.2 Kg/hr To elaborate: Material balance for air: 0.941000 = 0.98C, => C = 959.2 Kg/hr.

Discussion

9.	What is the value of H/P in the following process, if 2P + H = 16?(a) 1(b) 3(c) 6(d) 8The question was asked in homework.My doubt is from Material Balances Problems Involving Multiple Units topic in portion The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The correct OPTION is (c) 6 Easiest explanation: P + 20 = H + 10, => H – P = 10, solving both EQUATIONS, we get H = 12, P = 2, => H/P = 6.

Discussion

10.	What is the value of P in the following process?(a) 5 mole(b) 10 mole(c) 15 mole(d) 20 moleI had been asked this question in homework.My doubt stems from Material Balances Problems Involving Multiple Units topic in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The correct ANSWER is (a) 5 mole The explanation is: 10 = P + 5, => P = 5 mole.

Discussion

11.	What is the value of F*P in the following process?(a) 25(b) 125(c) 150(d) 225The question was asked in an interview for internship.Origin of the question is Material Balances Problems Involving Multiple Units topic in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» CORRECT ANSWER is (b) 125 Easiest explanation: F = 15 + 10 = 25 mole, P + 20 = F = 25, => P = 5 mole, => F*P = 125.

Discussion

12.	What is the value of P in the following process?(a) 5 mole(b) 15 mole(c) 25 mole(d) 35 moleThe question was posed to me during an internship interview.I want to ask this question from Material Balances Problems Involving Multiple Units topic in portion The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The correct choice is (C) 25 mole Explanation: 10 + 20 = 5 + P, => P = 25 mole.

Discussion

13.	What is the value of P in the following process?(a) 5 mole(b) 10 mole(c) 15 mole(d) 20 moleI had been asked this question in my homework.My query is from Material Balances Problems Involving Multiple Units in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Right ANSWER is (c) 15 mole The best I can EXPLAIN: 10 + 20 = P + 10 + 5, => P = 15 mole.

Discussion

14.	Methane is at the rate 50 moles is supplied to a reactor with air at the rate 1000 moles, the reactor leaves O2, N2, CO2 and H2O, what is the percentage of N2 in products?(a) 25.4%(b) 45.2%(c) 75.2%(d) 95.6%The question was asked during an interview for a job.This interesting question is from Material Balances Involving Combustion in portion The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The CORRECT option is (C) 75.2% EASY explanation: The reaction is CH4 + 2O2 -> CO2 + 2H2O. O2 supplied = 100021/100 = 210 moles, N2 supplied = 100079/100 = 790 moles, => O2 unreacted = 210 – 100 = 110 moles, CO2 formed = 50 moles, H2O formed = 100 moles. => Percentage of N2 = 790/1050*100 = 75.2%.

Discussion

15.	Methane is at the rate 50 moles is supplied to a reactor with air at the rate 1000 moles, the reactor leaves O2, N2, CO2 and H2O, what is the percentage of H2O in products?(a) 5.8%(b) 9.5%(c) 15.4%(d) 20.7%This question was addressed to me in an internship interview.My question is taken from Material Balances Involving Combustion in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Right CHOICE is (b) 9.5% The EXPLANATION is: The reaction is CH4 + 2O2 -> CO2 + 2H2O. O2 supplied = 100021/100 = 210 moles, N2 supplied = 100079/100 = 790 moles, => Osub>2 unreacted = 210 – 100 = 110 moles, COsub>2 FORMED = 50 moles, Hsub>2O formed = 100 moles. => Percentage of H2O = 100/1050*100 = 9.5%.

Discussion

16.	Methane is at the rate 50 moles is supplied to a reactor with air at the rate 1000 moles, the reactor leaves O2, N2, CO2 and H2O, what is the percentage of CO2 in products?(a) 4.7%(b) 10.4%(c) 16.5%(d) 24.3%I had been asked this question in a national level competition.My query is from Material Balances Involving Combustion in chapter The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Right choice is (a) 4.7% The explanation is: The reaction is CH4 + 2O2 -> CO2 + 2H2O. O2 supplied = 100021/100 = 210 MOLES, N2 supplied = 100079/100 = 790 moles, => O2 unreacted = 210 – 100 = 110 moles, CO2 formed = 50 moles, H2O formed = 100 moles. => Percentage of CO2 = 50/1050*100 = 4.7%.

Discussion

17.	Methane is at the rate 50 moles is supplied to a reactor with air at the rate 1000 moles, the reactor leaves O2, N2, CO2 and H2O, what is the percentage of O2 in products?(a) 10.4%(b) 25.8%(c) 45.6%(d) 78.2%The question was posed to me by my college professor while I was bunking the class.Enquiry is from Material Balances Involving Combustion in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» RIGHT choice is (a) 10.4% Easiest explanation: The reaction is CH4 + 2O2 -> CO2 + 2H2O. O2 supplied = 100021/100 = 210 moles, N2 supplied = 100079/100 = 790 moles, => O2 unreacted = 210 – 100 = 110 moles, CO2 formed = 50 moles, H2O formed = 100 moles. => Percentage of O2 = 110/1050*100 = 10.4%.

Discussion

18.	Methane is at the rate 50 moles is supplied to a reactor with air at the rate 1000 moles, the reactor leaves O2, N2, CO2 and H2O, what is the rate of products?(a) 900 moles(b) 950 moles(c) 1000 moles(d) 1050 molesThe question was posed to me in exam.My question comes from Material Balances Involving Combustion in chapter The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Right choice is (d) 1050 moles For EXPLANATION: The reaction is CH4 + 2O2 -> CO2 + 2H2O. O2 supplied = 100021/100 = 210 moles, N2 supplied = 100079/100 = 790 moles, => O2 unreacted = 210 – 100 = 110 moles, CO2 FORMED = 50 moles, H2O formed = 100 moles. => Rate of products = 790 + 110 + 50 + 100 = 1050 moles.

Discussion

19.	Octane is burnt with 40% excess O2, what is the percentage of CO2 in products?(a) 18.18%(b) 36.36%(c) 54.54%(d) 72.72%I got this question in an interview for job.I would like to ask this question from Material Balances Involving Combustion topic in portion The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Correct choice is (B) 36.36% The BEST I can explain: The reaction is C8H18 + 12.5O2 -> 8CO2 + 9H2O. Basis: 10 moles of C8H18, => moles of O2 reacted = 125, => moles of O2 entered the PROCESS = 175, => moles of CO2, H2O and O2 in PRODUCTS are 80, 90 and 50, => percentage of CO2 = 80/220*100 = 36.36%.

Discussion

20.	Propane is burnt with 20% excess O2, what is the percentage of CO2 in products?(a) 12.5%(b) 25%(c) 45%(d) 75.5%This question was posed to me during an interview.My doubt stems from Material Balances Involving Combustion in portion The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» CORRECT OPTION is (a) 12.5% Explanation: The reaction is C3H8 + 5O2 -> 3CO2 + 4H2O. Basis: 10 MOLES of C3H8, => moles of O2 reacted = 50, => moles of O2 entered the process = 60, => moles of CO2, H2O and O2 in products are 30, 40 and 10, => percentage of CO2 = 10/80*100 = 12.5%.

Discussion

21.	Pentane is burnt with 100% of excess air, what is the percentage of H2O in the products?(a) 12.4%(b) 34.6%(c) 42.1%(d) 56.9%I have been asked this question in examination.The origin of the question is Material Balances Involving Combustion in portion The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Right OPTION is (c) 42.1% To explain: The reaction is C5H12 + 8O2 -> 5CO2 + 6H2O. Basis: 10 moles of C5H12, => moles of O2 reacted = 80, => moles of O2 entered the process = 160, => moles of CO2, H2O and O2 in products are 50, 60 and 80, => percentage of H2O = 80/190*100 = 42.1%.

Discussion

22.	Ethene is burnt with 150% of excess air, what is the percentage of O2 in the products?(a) 12.5%(b) 33.3%(c) 45.4%(d) 52.9%I have been asked this question in examination.My doubt stems from Material Balances Involving Combustion topic in chapter The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer»

Discussion

23.	Ethene is burnt with 50% of excess air, what is the percentage of CO2 in the products?(a) 11.11%(b) 36.36%(c) 66.66%(d) 72.72%This question was addressed to me during a job interview.My enquiry is from Material Balances Involving Combustion topic in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The CORRECT choice is (b) 36.36% For explanation I would say: The REACTION is C2H4 + 3O2 -> 2CO2 + 2H2O. Basis: 10 moles of C2H4, => moles of O2 reacted = 30, => moles of O2 ENTERED the process = 45, => moles of CO2, H2O and O2 in products are 20, 20 and 15 respectively, => percentage of CO2 = 20/55*100 = 36.36%.

Discussion

24.	144 grams of C5H12 is burnt with 64 grams O2, and 44 grams of CO2 is formed, what is the percentage of excess O2?(a) 25%(b) 50%(c) 75%(d) 100%I had been asked this question during an interview for a job.Query is from Material Balances Involving Combustion in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Correct option is (a) 25% The explanation is: The BALANCED chemical REACTION is C5H12 + 8O2 -> 5CO2 + 6H2O, => Extent of reaction = (44/44 – 0)/5 = 0.2. MOLES of O2 ENTERED the process = 64/32 = 2, Moles of O2 required = 0.28 = 1.6, => Percentage of excess oxygen = 100(2 – 1.6)/1.6 = 25%.

Discussion

25.	The extent of a reaction is 10, and the stoichiometric coefficient of O2 is 2.5, if the moles of O2 entering the process is 45, what is the percentage of excess air?(a) 20%(b) 40%(c) 60%(d) 80%I got this question during a job interview.I need to ask this question from Material Balances Involving Combustion topic in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Correct answer is (d) 80% To elaborate: MOLES of O2 REQUIRED = 102.5 = 25, => Percentage of excess air = 100(45 – 25)/25 = 80%.

Discussion

26.	What is the percentage of excess air if 50 grams of air is in excess and 150 grams of air enters the process?(a) 10%(b) 25%(c) 50%(d) 100%This question was addressed to me in an interview.The query is from Material Balances Involving Combustion in chapter The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The correct answer is (c) 50% Best explanation: Percentage of excess AIR = 100*50/(150 – 50) = 50%.

Discussion

27.	10 moles of ethane is supplied with 49 moles of oxygen, what is the percentage of excess oxygen?(a) 20%(b) 40%(c) 50%(d) 70%This question was addressed to me by my college professor while I was bunking the class.My doubt is from Material Balances Involving Combustion topic in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Correct option is (b) 40% For explanation I would say: The balanced REACTION is C2H6 + 3.5O2 -> 2CO2 + 3H2O, => O2 required = 3.510 = 35 moles, => percentage of excess oxygen = 100(49 – 35)/35 = 40%.

Discussion

28.	A reactor is supplied with 2 streams both at same rates, one has pure Cl2, and another has pure C2H6, if the product has 20% C2H5Cl and 50% HCl and 30% C2H6, what is the ratio of rate of feed and rate of product?(a) 0.2(b) 0.5(c) 2(d) 5This question was addressed to me in an interview for internship.I want to ask this question from Element Material Balances topic in chapter The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The correct option is (b) 0.5 For explanation: The reaction is C2H6 + CL2 -> C2H5Cl + HCl, LET the rate of feed and products be F and P respectively. ELEMENT balances, C: F(2) – 0.3P(2) = 0.2P(2), => F/P = 0.5.

Discussion

29.	What is the percentage of excess air, if 10 moles of air entered the process and only 5 moles of that are required?(a) 10%(b) 50%(c) 75%(d) 100%The question was posed to me in semester exam.I'd like to ask this question from Material Balances Involving Combustion topic in chapter The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» RIGHT answer is (d) 100% EXPLANATION: Percentage of excess AIR = 100*(10 – 5)/5 = 100%.

Discussion

30.	A reactor is supplied with 2 streams both at the rate 5 mole, one has 40% Cl2 and 60% N2, and another has pure C2H6, if the product has C2H5Cl, HCl and N2 at the rate 20 mole, what is the percentage of HCl in products?(a) 10%(b) 15%(c) 25%(d) 30%I have been asked this question in homework.This is a very interesting question from Element Material Balances in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Correct answer is (b) 15% For explanation: The reaction is C2H6 + Cl2 -> C2H5Cl + HCL, Let the fraction of C2H5Cl, HCl and N2 be x, y and (1 – x – y) respectively. ELEMENT balances, Cl: 0.45(2) = x10(1) + y10(1), => x + y = 0.4, C: 5(2) = x20(2), => x = 0.25, => y = 0.4 – 0.25 = 0.15, => percentage of HCl = 15%.

Discussion

31.	Ethane is supplied with chlorine in a reactor, how many independent element balances can you write?(a) 1(b) 2(c) 3(d) 4This question was posed to me in an international level competition.I need to ask this question from Element Material Balances topic in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The correct ANSWER is (c) 3 Easy explanation: The reaction is C2H6 + Cl2 -> C2H5Cl + HCl, Element balance C: 2F = 2xP, H: 6F = 5xP + (1 – x)P, CL: 2W = xP + (1 – x)P, => The equations are F = xP, 6F = 4xP + P, and 2W = P, which are INDEPENDENT.

Discussion

32.	A reactor is supplied with 2 streams both at same rates, one has pure Cl2, and another has pure C2H6, if the product has 20% C2H5Cl and 80% HCl, what is the ratio of rate of feed and rate of product?(a) 0.2(b) 0.5(c) 2(d) 5I had been asked this question during an interview.I'd like to ask this question from Element Material Balances in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Right CHOICE is (a) 0.2 The explanation is: The reaction is C2H6 + Cl2 -> C2H5Cl + HCl, Let the rate of feed and products be F and P RESPECTIVELY. ELEMENT balances, C: F(2) = 0.2P(2), => F/P = 0.2.

Discussion

33.	Ethane is supplied at the rate F with oxygen at the rate W and leaves the following products CO2, H2O, O2, C2H6 and H2 at the rate P. How many independent element balances are possible?(a) 1(b) 2(c) 3(d) 4I have been asked this question in homework.The above asked question is from Element Material Balances in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» CORRECT option is (c) 3 To explain I would say: The reaction is C2H6 + 3.5O2 -> 2CO2 + 3H2O, since there are three elements C, H and O, we can WRITE 3 independent material balances.

Discussion

34.	A reactor is supplied with 10 moles glucose and excess oxygen to produce CO2 and H2O, if the rate of products is 25 moles, what is the percentage of CO2 in the products?(a) 0.1(b) 0.2(c) 0.3(d) 0.4This question was posed to me during an interview.This question is from Element Material Balances in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The correct choice is (d) 0.4 Easy EXPLANATION: The REACTION is C6H12O6 + 6O2 -> 6CO2 + 6H2O. Let the fraction of CO2 be X, ELEMENT balances, C: 10(6) = 6x5(1), => x = 0.4.

Discussion

35.	A reactor is supplied with 10 moles glucose and excess oxygen to produce 40% CO2, 60% H2O, what is the rate of products?(a) 25 mole(b) 50 mole(c) 75 mole(d) 100 moleThe question was posed to me in an online quiz.This interesting question is from Element Material Balances topic in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» CORRECT answer is (a) 25 mole Explanation: The reaction is C6H12O6 + 6O2 -> 6CO2 + 6H2O, Let the rate of products be P. Element BALANCES, C: 10(6) = 6*0.4P(1), => P = 25 mole.

Discussion

36.	A reactor is supplied with glucose and oxygen to produce 40% CO2, 60% H2O, what is the ratio of glucose reacted and products?(a) 0.2(b) 0.4(c) 0.6(d) 0.8This question was addressed to me in final exam.This key question is from Element Material Balances topic in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Correct option is (B) 0.4 Best EXPLANATION: The reaction is C6H12O6 + 6O2 -> 6CO2 + 6H2O, Let the rate of glucose and products be F and P, Element balances, C: F(6) = 6*0.4P(1), => F/P = 0.4.

Discussion

37.	A reactor is supplied with 10 mole of Hexane and some hydrogen to produce 20% methane, 30% propane and 50% butane, what is the rate of products?(a) 10 mole(b) 16.6 mole(c) 26.6 mole(d) 40 moleThe question was posed to me in an interview for job.The question is from Element Material Balances topic in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» CORRECT answer is (c) 26.6 mole Easiest explanation: The reaction is 2C6H14 + 2H2 -> CH4 + 2C3H8 + C5H12, LET the rate of products be P. Element BALANCE, C: 210(6) = 0.2P(1) + 20.3P(3) + 0.5P(5), => 120 = 4.5P, => P = 26.6 mole.

Discussion

38.	A reactor is supplied with Hexane and hydrogen to produce 20% methane, 30% propane and 50% butane, what is the ratio of hydrogen consumed and the hexane reacted?(a) 0.21(b) 0.45(c) 0.59(d) 0.73I got this question in final exam.My question is based upon Element Material Balances topic in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Right option is (d) 0.73 To EXPLAIN I would say: The reaction is 2C6H14 + 2H2 -> CH4 + 2C3H8 + C5H12, Let the rate of Hexane, hydrogen and products be F, W and P RESPECTIVELY. Element BALANCES, C: 2F(6) = 0.2P(1) + 20.3P(3) + 0.5P(5), => 8F = 3P, H: 2F(14) + 2W(2) = 0.2P(4) + 20.3P(8) + 0.5P(12), => 7F + W = 2.9P, => W/F= 2.2/3 = 0.73.

Discussion

39.	A reactor supplied with CO2 and H2O, the product contains CO2, H2O and H2CO3, if the rate of products is 10 mole and percentage of CO2 in products is 20%, what is the feed rate of H2O?(a) 2 mole(b) 4 mole(c) 8 mole(d) 10 moleThe question was posed to me in quiz.The question is from Element Material Balances in portion The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» RIGHT choice is (C) 8 MOLE Easy explanation: The reaction is CO2 + H2O -> H2CO3. Let the rate of H2O be W, and percentage of H2O in products be x. Material balances, H: W(2) = x10(2) + (1 – x – 0.2)10(2), => W = 8 mole.

Discussion

40.	A reactor supplied with CO2 and H2O, the product contains 40% CO2, 30% H2O and 30% H2CO3, what is the ratio of feed rate of CO2 and rate of products?(a) 0.3(b) 0.4(c) 0.7(d) 0.9I had been asked this question in quiz.I want to ask this question from Element Material Balances in chapter The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Right answer is (c) 0.7 Explanation: The REACTION is CO2 + H2O -> H2CO3. LET the rate of CO2, H2O and H2CO3 be F, W and P RESPECTIVELY. Element balances, C: F(1) = 0.4P(1) + 0.3P(1), => F/P = 0.7.

Discussion

41.	A reactor supplied with CO2 and H2O, the product contains H2O and H2CO3, if the rate of H2O is 10 mole, what is the rate of products?(a) 5 mole(b) 10 mole(c) 15 mole(d) 20 moleThis question was addressed to me in exam.Asked question is from Element Material Balances topic in chapter The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The correct option is (b) 10 MOLE For explanation I would SAY: The reaction is CO2 + H2O -> H2CO3. Let the RATE of products be P, and the FRACTION of H2CO3 in products be x, material balances, H: 10(2) = xP(2) + (1 – x)P(2), => P = 10 mole.

Discussion

42.	A reactor supplied with CO2 and H2O, the product contains H2O and H2CO3, if the rate of CO2 is 10 mole, what is the percentage of H2CO3 in products?(a) 10(b) 50(c) 75(d) 100I got this question by my college director while I was bunking the class.My question comes from Element Material Balances in chapter The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» The correct answer is (d) 100 To elaborate: The reaction is CO2 + H2O -> H2CO3. Let the RATE of CO2 and H2O and product be F and W respectively, and the fraction of H2CO3 in products be x. ELEMENT balances, C: F(1) = x*10(1), => F = 10X, => x = 1, => percentage of H2CO3 = 100%.

Discussion

43.	A reactor supplied with CO2 and H2O, the product contains 10% H2CO3 and 90% H2O, what is the feed rate of CO2, if the rate of product is 50 mole?(a) 5 mole(b) 10 mole(c) 25 mole(d) 50 moleThe question was asked at a job interview.I want to ask this question from Element Material Balances topic in chapter The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Correct option is (a) 5 mole For explanation I would SAY: The reaction is CO2 + H2O -> H2CO3. Let the RATES of CO2 and H2O be F and W RESPECTIVELY. Element BALANCES, C: F(1) = 0.1P(1), => 10F = P, => F = 5 mole.

Discussion

44.	A reactor is supplied with 45 moles of C, and it undergoes following reactions C + 0.5O2 -> CO and C + O2 -> CO2, if 25 moles of CO2 was produced and 6 moles of C remains unreacted, what are the number of moles of CO produced?(a) 6(b) 9(c) 14(d) 17The question was asked during an internship interview.My question is based upon Processes Involving Multiple Units topic in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Right option is (c) 14 Easy explanation: Extent of second REACTION = (25 – 0)/1 = 25, => moles of C reacted in second reaction = 251 = 25, => moles of C reacted in first reaction = 45 – 25 – 6 = 14, => extent of first reaction = (0 – 14)/(-1) = 14, => moles of CO produced = 141 = 14.

Discussion

45.	A reactor is supplied with 20 moles of C, and it undergoes following reactions C + 0.5O2 -> CO and C + O2 -> CO2, if 10 moles of CO2 was produced and 5 moles of C remains unreacted, what are the number of moles of CO produced?(a) 1(b) 3(c) 5(d) 7This question was addressed to me by my college director while I was bunking the class.My question is taken from Processes Involving Multiple Units in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Right OPTION is (c) 5 The BEST explanation: Extent of SECOND reaction = (10 – 0)/1 = 10, => MOLES of C reacted in second reaction = 101 = 10, => moles of C reacted in first reaction = 20 – 10 – 5 = 5, => extent of first reaction = (0 – 5)/(-1) = 5, => moles of CO produced = 51 = 5.

Discussion

46.	A reactor is supplied with 25 moles of C, and it undergoes following reactions C + 0.5O2 -> CO and C + O2 -> CO2, if 13 moles of CO2 was produced and 5 moles of C remains unreacted, what are the number of moles of CO produced?(a) 1(b) 3(c) 5(d) 7This question was addressed to me in unit test.Query is from Processes Involving Multiple Units in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» RIGHT choice is (d) 7 For explanation: Extent of second reaction = (13 – 0)/1 = 13, => moles of C reacted in second reaction = 131 = 13, => moles of C reacted in first reaction = 25 – 13 – 5 = 7, => extent of first reaction = (0 – 7)/(-1) = 7, => moles of CO produced = 71 = 7.

Discussion

47.	A reactor is supplied with 15 moles of C, and it undergoes following reactions C + 0.5O2 -> CO and C + O2 -> CO2, if 8 moles of CO2 was produced and 3 moles of C remains unreacted, what are the number of moles of CO produced?(a) 1(b) 2(c) 3(d) 4This question was addressed to me in my homework.Asked question is from Processes Involving Multiple Units in division The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» RIGHT choice is (d) 4 Easy explanation: Extent of second reaction = (8 – 0)/1 = 8, => moles of C reacted in second reaction = 81 = 8, => moles of C reacted in first reaction = 15 – 8 – 3 = 4, => extent of first reaction = (0 – 4)/(-1) = 4, => moles of CO PRODUCED = 41 = 4.

Discussion

48.	A reactor is supplied with 5 moles of C4H10, and it undergoes following reactions C4H10 + 4H2O -> 4CO + 9H2 and C4H10 + 6.5O2 -> 4CO2 + 5H2O, if 8 moles of CO2 was produced and 2 moles of C4H10 remains unreacted, what are the number of moles of CO produced?(a) 1(b) 2(c) 3(d) 4This question was addressed to me at a job interview.My enquiry is from Processes Involving Multiple Units in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer»

Discussion

49.	A reactor is supplied with 12 moles of C, and it undergoes following reactions C + 0.5O2 -> CO and C + O2 -> CO2, if 4 moles of CO2 was produced and 4 moles of C remains unreacted, what are the number of moles of CO produced?(a) 1(b) 2(c) 3(d) 4The question was posed to me in an online interview.My query is from Processes Involving Multiple Units topic in section The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer»

Discussion

50.	A reactor is supplied with 5 moles of C4H10, and it undergoes following reactions C4H10 + 4H2O -> 4CO + 9H2 and C4H10 + 6.5O2 -> 4CO2 + 5H2O, if 8 moles of CO2 was produced and 2 moles of C4H10 remains unreacted, what are the number of moles of water produced?(a) 2(b) 5(c) 7.5(d) 10This question was addressed to me in an interview.I'm obligated to ask this question of Processes Involving Multiple Units topic in portion The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering
Answer» Right ANSWER is (d) 10 To explain: EXTENT of second reaction = (8 – 0)/4 = 2, => moles of water produced = 5*2 = 10.

Discussion

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