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1.

Find out the incorrect statement(a) Accumulation for a process can be negative(b) Accumulation for a process can be positive(c) Accumulation for a process can be zero(d) None of the mentionedI got this question in exam.This interesting question is from Material Balances -III topic in portion Material Balances of Chemical Process Calculation

Answer» RIGHT ANSWER is (d) NONE of the mentioned

The best I can explain: ACCUMULATION for a process can be NEGATIVE, positive and zero.
2.

A ____________ is one in which material enters and leaves the system without interruption.(a) Continuous process(b) Batch process(c) Semi-batch process(d) None of the mentionedThe question was asked at a job interview.My question is based upon Material Balances -III in section Material Balances of Chemical Process Calculation

Answer»

The correct OPTION is (a) CONTINUOUS process

Easiest EXPLANATION: A continuous is one in which material enters and leaves the system WITHOUT INTERRUPTION.

3.

A system that does not have material crossing the system boundary is called(a) Closed System(b) Open System(c) Steady state system(d) None of the mentionedI got this question during an interview.My question comes from Material Balances -II topic in section Material Balances of Chemical Process Calculation

Answer»

Right CHOICE is (a) Closed System

For EXPLANATION I WOULD say: A system that does not have MATERIAL crossing the system BOUNDARY is called Closed System.

4.

Material balance equation cannot be applied to(a) Total moles(b) Mass of an atomic species(c) Moles of an atomic species(d) All of the mentionedThe question was asked during an online interview.Enquiry is from Material Balances -I in chapter Material Balances of Chemical Process Calculation

Answer»

Right choice is (a) TOTAL MOLES

The best explanation: Total moles MAY VARY.

5.

A depletion of material in a system is called ______________(a) Accumulation(b) Negative accumulation(c) Positive accumulation(d) None of the mentionedThe question was asked in an interview for job.This key question is from Material Balances -II topic in chapter Material Balances of Chemical Process Calculation

Answer»

The correct ANSWER is (B) NEGATIVE accumulation

Best explanation: A DEPLETION of MATERIAL in a system is called Negative accumulation.

6.

_________ is the line that encloses the portion of the process that you want to analyse.(a) System(b) Surrounding(c) System Boundary(d) None of the mentionedI got this question during a job interview.This intriguing question comes from Material Balances -II in division Material Balances of Chemical Process Calculation

Answer» CORRECT answer is (c) System BOUNDARY

Best EXPLANATION: System Boundary is the line that encloses the portion of the process that you want to ANALYSE.
7.

A fluid enters system at the rate of 10 liters/sand leaves in two pathways one with 7 liters/s, then what type of flow it is?(a) Steady-state(b) Unsteady-state(c) Cannot say(d) None of the mentionedI got this question in an online quiz.The question is from Material Balances -V topic in chapter Material Balances of Chemical Process Calculation

Answer»

Right ANSWER is (b) Unsteady-state

The BEST I can explain: Since the flow in rate and flow out rate of the fluid are not EQUAL, the system is in Unsteady-state.

8.

If A = 100 moles, what are the number of moles of C?(a) 151.4(b) 161.4(c) 171.4(d) 181.6I got this question in an international level competition.My query is from Material Balances -IV in chapter Material Balances of Chemical Process Calculation

Answer» CORRECT OPTION is (C) 171.4

To ELABORATE: Σxi = 1.
9.

What is the mass fraction of NaOH in A?(a) 0.2(b) 0.4(c) 0.6(d) 0.8The question was posed to me in an online interview.My query is from Material Balances -IV in section Material Balances of Chemical Process Calculation

Answer»

Right OPTION is (d) 0.8

The EXPLANATION is: ΣωI = 1 and ΣωIWi = 0 for each COMPONENT.

10.

Unsteady state system is also known as(a) Open system(b) Closed system(c) Transient system(d) None of the mentionedI had been asked this question during an online exam.This is a very interesting question from Material Balances -III topic in section Material Balances of Chemical Process Calculation

Answer» CORRECT ANSWER is (c) TRANSIENT system

Explanation: UNSTEADY state system is also known as transient system.
11.

Soup preparation is an example of _______where nothing is added in between the process.(a) Continuous process(b) Batch process(c) Semi-batch process(d) None of the mentionedThe question was asked in an online quiz.Question is taken from Material Balances -III topic in division Material Balances of Chemical Process Calculation

Answer»

Right choice is (B) Batch process

For explanation I would say: Batch process TREATS a FIXED amount of material.

12.

In a process, two feed A(400Kg) and B(400 Kg) is given. If the conversion is 50% and A & B converts in equal proportion, what is the weight of the product formed?(a) 200 Kg(b) 400 Kg(c) 600 Kg(d) 800 KgI got this question during an interview.Query is from Material Balances -VI topic in section Material Balances of Chemical Process Calculation

Answer»

Right option is (b) 400 Kg

For EXPLANATION I WOULD say: Product = (400*.05 + 400*0.5).

13.

What is the value of ω2 for A?(a) 0.5(b) 0.6(c) 0.7(d) 0.8The question was posed to me in exam.My doubt is from Material Balances -I topic in section Material Balances of Chemical Process Calculation

Answer»

The CORRECT ANSWER is (a) 0.5

For EXPLANATION I would SAY: Σω = 1.

14.

For a given system, Accumulation = Input – Output, where both the terms are distinct and non-zero, then the system(a) Steady-state(b) Closed(c) Non-reactive(d) None of the mentionedThe question was asked in an online interview.Question is taken from Material Balances -VI in section Material Balances of Chemical Process Calculation

Answer» CORRECT option is (C) Non-reactive

Best explanation: There is no mention of GENERATION and CONSUMPTION so it is a non-reactive system.
15.

The human body is _________(a) Closed System(b) Open System(c) Isolated System(d) None of the mentionedThe question was asked in homework.This key question is from Material Balances -V in section Material Balances of Chemical Process Calculation

Answer»

Correct CHOICE is (B) Open System

Explanation: Since AIR, WATER and food is GOING in and out of a human body, it’s an open system.

16.

A bucket of water is filled with oil. What kind of system is this?(a) Open(b) Closed(c) Transient(d) None of the mentionedI got this question in semester exam.This is a very interesting question from Material Balances -V in section Material Balances of Chemical Process Calculation

Answer»

Right CHOICE is (B) Closed

Easiest explanation: OIL is NEITHER ENTERING nor leaving.

17.

If A = 100 moles, what are the number of moles of B?(a) 51.4(b) 61.4(c) 71.4(d) 81.6I have been asked this question in exam.I'd like to ask this question from Material Balances -IV in chapter Material Balances of Chemical Process Calculation

Answer»

The CORRECT ANSWER is (C) 71.4

To EXPLAIN: Σxi = 1.

18.

What is the product stream of CO2?(a) 1.25 Kg/s(b) 2.50 Kg/s(c) 3.75 Kg/s(d) 5.00 Kg/sI have been asked this question in my homework.Question is taken from Material Balances -VI in chapter Material Balances of Chemical Process Calculation

Answer»

Correct OPTION is (B) 2.50 Kg/s

To explain: Mass fraction will be CONSTANT for PRODUCT stream as well.

19.

For a given system, Accumulation = Generation – Consumption, where both the terms are distinct and non-zero, then the system is(a) Steady-state(b) Closed(c) Non-reactive(d) None of the mentionedThis question was addressed to me by my school principal while I was bunking the class.I want to ask this question from Material Balances -VI topic in section Material Balances of Chemical Process Calculation

Answer» RIGHT option is (b) CLOSED

Best explanation: There is no mention of input and OUTPUT so it is a closed system.
20.

Wine pouring in a glass is an example of(a) Batch(b) Semi-batch(c) Neither of them(d) Both of themI had been asked this question by my college director while I was bunking the class.My enquiry is from Material Balances -V in chapter Material Balances of Chemical Process Calculation

Answer»

The correct OPTION is (b) Semi-batch

For EXPLANATION: WINE enters but doesn`t LEAVE, it`s a semi-batch.

21.

The depletion of a component in a system due to chemical reaction is _________(a) Consumption(b) Degradation(c) Decomposition(d) None of the mentionedThe question was asked in quiz.The query is from Material Balances -III in portion Material Balances of Chemical Process Calculation

Answer»

Right answer is (a) Consumption

To EXPLAIN I would say: The depletion of a COMPONENT in a SYSTEM due to CHEMICAL REACTION is consumption.

22.

An increase or decrease in the material in a system is called _________(a) Accumulation(b) Negative accumulation(c) Positive accumulation(d) None of the mentionedThe question was posed to me in unit test.The question is from Material Balances -II topic in division Material Balances of Chemical Process Calculation

Answer» RIGHT answer is (a) Accumulation

To elaborate: An INCREASE or DECREASE in the material in a SYSTEM is CALLED accumulation.
23.

Material balance equation can be applied to(a) Total mass(b) Mass of a component(c) Moles of a component(d) All of the mentionedI got this question in homework.Origin of the question is Material Balances -I topic in division Material Balances of Chemical Process Calculation

Answer»

The correct answer is (d) All of the mentioned

Best explanation: Material BALANCE EQUATION can be applied to all these as these are conserved under every CHANGE in a chemical process.

24.

A semi-batch process differ from an open process in ________(a) Input(b) Output(c) Generation(d) ConsumptionI have been asked this question in final exam.Enquiry is from Material Balances -V topic in portion Material Balances of Chemical Process Calculation

Answer»

The correct answer is (b) OUTPUT

The best I can EXPLAIN: A semi-batch PROCESS does not have output, while an OPEN system has output.

25.

In a process, two feed streams are there and one output stream. The feed streams have the feed rates as 500 kg/sec and 600 kg/sec. If the output stream rate is 800 kg/s, what is the mass stored in the chamber in five seconds?(a) 300 kg(b) 500 kg(c) 1000 kg(d) 1500 kgThis question was posed to me in unit test.This is a very interesting question from Material Balances -I in section Material Balances of Chemical Process Calculation

Answer» CORRECT option is (d) 1500 kg

To EXPLAIN: For five seconds, ACCUMULATION = 5(500+600-800) Kg.
26.

A reaction has reactants 1 moles of H2O and 1 mole of NaCl, and products NaOH and HCl, what are the total moles of products?(a) 1(b) 2(c) 3(d) 4I got this question in an interview for internship.Origin of the question is Material Balances -V in chapter Material Balances of Chemical Process Calculation

Answer»

Correct ANSWER is (b) 2

Easy explanation: In the PRODUCT there is one MOLE of NAOH and one mole of HCl is produced.

27.

Concept of material balance based upon?(a) Conservation of mass(b) Conservation of energy(c) Conservation of momentum(d) Conservation of VolumeThis question was posed to me during an online exam.Query is from Material Balances -IV in chapter Material Balances of Chemical Process Calculation

Answer»

Correct option is (a) Conservation of MASS

To explain: Material BALANCE is BASED on conservation of mass.

28.

A process in which material enters the system but product is not removed during operation is called(a) Continuous process(b) Batch process(c) Semi-batch process(d) None of the mentionedThis question was addressed to me in homework.The above asked question is from Material Balances -III in portion Material Balances of Chemical Process Calculation

Answer»
29.

A system in which all conditions remain constant with time is called(a) Open system(b) Closed system(c) Steady state system(d) None of the mentionedI had been asked this question in an interview for job.I'd like to ask this question from Material Balances -II in portion Material Balances of Chemical Process Calculation

Answer»

The CORRECT choice is (c) Steady STATE system

Best EXPLANATION: A system in which all CONDITIONS remain constant with TIME is called Steady state system.

30.

In a process, 5 Kgs of water is added to a container and after some interval 3 Kgs of water is taken out. If finally there is 7 Kgs of water then how much water was there in the very beginning?(a) 5 Kg(b) 10 Kg(c) 15 Kg(d) 20 KgThis question was addressed to me in unit test.I'd like to ask this question from Material Balances -V in portion Material Balances of Chemical Process Calculation

Answer»

The correct option is (a) 5 Kg

The explanation is: Final CONDITION = Initial condition + SUM of inputs – sum of OUTPUTS.

31.

What is the product stream of H2O?(a) 2.5(b) 3.5(c) 7.5(d) 10.5The question was posed to me during an interview.I want to ask this question from Material Balances -VI in chapter Material Balances of Chemical Process Calculation

Answer»

Correct OPTION is (c) 7.5

To explain I would SAY: MASS fraction will be constant for PRODUCT STREAM as well.

32.

What is the mass fraction of H2O in A?(a) 0.2(b) 0.4(c) 0.6(d) 0.8The question was asked in an interview.The above asked question is from Material Balances -IV in portion Material Balances of Chemical Process Calculation

Answer»

Correct CHOICE is (a) 0.2

The EXPLANATION: ΣωI = 1 and ΣωIWi = 0 for each COMPONENT.

33.

Any arbitrary portion of or whole process that is considered for analysis is called(a) System(b) Boundary(c) Surrounding(d) None of the mentionedThis question was posed to me during an interview.Enquiry is from Material Balances -II in division Material Balances of Chemical Process Calculation

Answer»

The correct choice is (a) System

To EXPLAIN I would say: Any arbitrary PORTION of or whole process that is CONSIDERED for analysis is CALLED system.

34.

5 moles of O2 is added to 5 moles of H2, how many moles of H2O will it produce?(a) 5(b) 10(c) 15(d) 20The question was asked in homework.My question is from Material Balances -V topic in division Material Balances of Chemical Process Calculation

Answer»

The correct ANSWER is (b) 10

Best explanation: Per mole of OXYGEN & Hydrogen there is TWO moles of WATER.

35.

What ids the value of ω2 for P?(a) 0.98(b) 0.88(c) 0.78(d) 0.68I have been asked this question during an internship interview.I would like to ask this question from Material Balances -I in division Material Balances of Chemical Process Calculation

Answer» RIGHT OPTION is (d) 0.68

Best EXPLANATION: ω2F + ω2A = ω2P.
36.

A fluid enters system at the rate of 10 liters/sand leaves in two pathways one with 7 liters/s and other with 3 liters/s, then what type of flow it is?(a) Steady-state(b) Unsteady-state(c) Cannot say(d) None of the mentionedThe question was asked at a job interview.I want to ask this question from Material Balances -V in chapter Material Balances of Chemical Process Calculation

Answer» RIGHT answer is (a) Steady-state

To explain I would say: SINCE the flow in RATE and flow out rate of the fluid are EQUAL, the system is in steady-state.
37.

______________is a process in which material is neither added nor removed from a process during operation.(a) Continuous process(b) Batch process(c) Semi-batch process(d) None of the mentionedI have been asked this question in an international level competition.This question is from Material Balances -III in division Material Balances of Chemical Process Calculation

Answer»

Correct choice is (B) Batch process

Easiest explanation: Batch process is a process in which MATERIAL is neither ADDED nor removed from a process during operation.

38.

Open system is also called a _______ system.(a) Flow(b) Free(c) Steady(d) None of the mentionedI have been asked this question in class test.The query is from Material Balances -II in chapter Material Balances of Chemical Process Calculation

Answer»

Right OPTION is (a) Flow

Explanation: Open system is also CALLED a flow system.

39.

If feed of 100 tonnes per hour at 5% concentration is fed to a crystallizer, the product obtained at 25% concentration is equal to ___________tonnes per hour.(a) 20(b) 25(c) 35(d) 40I got this question in an international level competition.This is a very interesting question from Material Balances -VI topic in division Material Balances of Chemical Process Calculation

Answer» RIGHT choice is (a) 20

To EXPLAIN: Mass BALANCE for the FEED.
40.

What is the mass in kg of H2O in feed and NaOH in product?(a) 65 and 50(b) 95 and 50(c) 65 and 75(d) 50 and 50I have been asked this question in quiz.The above asked question is from Material Balances -IV topic in division Material Balances of Chemical Process Calculation

Answer»

The correct ANSWER is (c) 65 and 75

Easiest EXPLANATION: ΣωI = 1 and mi= ωIW.

41.

A volatile solid material is placed in a tube and vacuum is created inside the tube. If the tube is heated and the solid vaporizes the weight of the material + tube will(a) Decrease(b) Increase(c) Remains same(d) None of the mentionedThe question was posed to me in examination.This key question is from Material Balances -III topic in chapter Material Balances of Chemical Process Calculation

Answer»

Right answer is (C) REMAINS same

For explanation I would SAY: Apply mass CONSERVATION.

42.

We don`t use volume balance in a chemical process because(a) Mass is not conserved in a process(b) Volume is not conserved in a process(c) Both a and b(d) Neither a nor bThis question was posed to me in unit test.My doubt stems from Material Balances -I topic in section Material Balances of Chemical Process Calculation

Answer»

Correct ANSWER is (b) Volume is not conserved in a process

Best EXPLANATION: Volume is not conserved in a process because different MATERIALS have different DENSITIES.

43.

A system in which one or more than one conditions vary with time is called(a) Open system(b) Closed system(c) Steady state system(d) Unsteady state systemThis question was posed to me in homework.Asked question is from Material Balances -III in portion Material Balances of Chemical Process Calculation

Answer»

Correct answer is (d) Unsteady STATE SYSTEM

For explanation I would say: A system in which ONE or more than one conditions VARY with time is called Unsteady state system.

44.

In the given tank, there are two feeds and one output. Consider a 2 hour operation; the feed rates are 4000 kg/hr and 6000 kg/hr. The accumulated material inside the tank is 2000 kg. What is the output rate kg/hr of the material?(a) 9000(b) 8000(c) 7000(d) 6000I had been asked this question by my school teacher while I was bunking the class.Question is from Material Balances -I in division Material Balances of Chemical Process Calculation

Answer»

The CORRECT ANSWER is (a) 9000

Explanation: INPUT = output, TAKE a basis: 2 hour.