Canned poultry is more often spoiled by

Saccharolytic Clostridia than by putrefactive

putrefactive than by Saccharolytic Clostridia

Saccharolytic Clostridia than by putrefactive

Heating always results in an increase in temperature. The statement isa) Correctb) Incorrectc) Always correctd) None of the mentioned 4-8. Q = UA(T2-T1); A formula for heat transfer is givenwhere: Q – Rate of Heat transfer U – Empirical constant (T2-T1) – Temperature difference between surrounding and system4. When Q < 0

Always correctd) None of the mentioned 4-8. Q = UA(T2-T1); A formula for heat transfer is givenwhere: Q – Rate of Heat transfer U – Empirical constant (T2-T1) – Temperature difference between surrounding and system4. When Q < 0a) Heat is transferred from systemb) Heat is transferred from surroundingc) Heat is gained by system

Correctb) Incorrectc) Always correctd) None of the mentioned 4-8. Q = UA(T2-T1); A formula for heat transfer is givenwhere: Q – Rate of Heat transfer U – Empirical constant (T2-T1) – Temperature difference between surrounding and system4. When Q < 0a) Heat is transferred from system

Incorrectc) Always correctd) None of the mentioned 4-8. Q = UA(T2-T1); A formula for heat transfer is givenwhere: Q – Rate of Heat transfer U – Empirical constant (T2-T1) – Temperature difference between surrounding and system4. When Q < 0a) Heat is transferred from systemb) Heat is transferred from surrounding

Always correctd) None of the mentioned 4-8. Q = UA(T2-T1); A formula for heat transfer is givenwhere: Q – Rate of Heat transfer U – Empirical constant (T2-T1) – Temperature difference between surrounding and system4. When Q < 0a) Heat is transferred from systemb) Heat is transferred from surroundingc) Heat is gained by system

None of the mentioned 4-8. Q = UA(T2-T1); A formula for heat transfer is givenwhere: Q – Rate of Heat transfer U – Empirical constant (T2-T1) – Temperature difference between surrounding and system4. When Q < 0a) Heat is transferred from systemb) Heat is transferred from surroundingc) Heat is gained by systemd) None of the mentionedView Answer

If one of the two fluids flowing through a heat exchanger of NTU = 2 remains at constant temperature throughout the exchanger length, the effectiveness of the heat exchanger will be

\(\dfrac{{1 - {e^{ - 2}}}}{2}\)

Heat treatment of metal is necessary

To make good appearance on the component

To produce certain desired properties

To make good appearance on the component

To decrease strength of the metal

For the same inlet and exit temperatures of the hot and cold fluids, the Log mean temperature difference (LMTD) is

Same for both parallel and counter flow heat exchangers.

Greater for parallel flow heat exchangers than the counter flow heat exchanger

Greater for counter flow heat exchanger than the parallel flow heat exchanger.

Same for both parallel and counter flow heat exchangers.

Depending on the properties of fluid.

In heat exchangers, the degree of approach is defined as the difference between temperatures of

Hot medium outlet and cold water outlet

Hot medium outlet and cold water inlet

Hot medium outlet and cold water outlet

A fan is provided in the water cooling system to

Provide drive to the water pump.

Draw the air through the radiator.

Provide drive to the water pump.

Cool the engine by blowing air over it.

Effectiveness (ε) and NTU relation for condenser may be written as

\({\rm{\varepsilon }} = \frac{{NTU}}{{1 + NTU}}\)

Air can be best heated by steam in a heat exchanger of

Double pipe type with fins on steam side

Double pipe type with fins on air side

In shell and tube heat exchanger, baffles are mainly used for

Direct the flow in desired direction

Reduce fouling of the tube surface

Increase the heat transfer area

Case hardening of steel

Involves diffusion of carbon & nitrogen in the surface of steel above the critical temperature on heating

Is the hardening of the casing or surface of steel above steel by proper heat treatment

Involves diffusion of carbon & nitrogen in the surface of steel above the critical temperature on heating

Is the saturation of surface of steel with any element by its diffusion from the surrounding medium at high temperature

In a double-pipe heat exchanger, the cold fluid is water with an inlet temperature 20°C and mass flow rate 20 kg/s and the hot fluid water inlet temperature 80°C and mass flow rate 10 kg/s. Assume that for water Cp = 4.2 kJ/kg°C, independent of temperature. What is the maximum temperature to which the cold fluid can be heated in a parallel flow and in a counter flow heat exchanger?

40°C in parallel flow and 80°C in counter flow

80°C in both parallel flow and counter flow

50°C in both parallel flow and counter flow

40°C in parallel flow and 50°C in counter flow

40°C in parallel flow and 80°C in counter flow

For a specified inlet and outlet temperatures, for which kind of heat exchange will the log mean temperature difference, ΔTlm will be highest?

Double pipe parallel-flow heat exchanger

Double pipe counter flow heat exchanger

Multi-pass shell and tube heat exchanger

In a concentric double-pipe heat exchanger where one of the fluids undergoes phase change

The two fluids should flow opposite to each other

The two fluids should flow parallel to each other

The two fluids should flow normal to each other

The directions of flow of the two fluids are of no consequence

In counter flow heat exchangers between two fluids

Both the fluids at exit are in their hottest state

Both the fluids at inlet are in their hottest state

Both the fluids at exit are in their hottest state

One fluid in hottest state and the other in coldest state

Any combination possible depending heat exchanger design

In a shell and tube heat exchanger, baffles are provided on the shell side to ______

Prevent the stagnation of shell side fluid

Effectiveness of heat exchanger is function of:

Surface area of heat exchanger only

341 + Mcqs in Heat in Chemical Process Calculation Page 1 McqOptions

1.	Canned poultry is more often spoiled by
A.	putrefactive than by Saccharolytic Clostridia
B.	Saccharolytic Clostridia than by putrefactive
C.	Saccharomyces species
D.	Micrococcus species
Answer» B. Saccharolytic Clostridia than by putrefactive

2.	Sulfur stinker spoilage, caused by is uncommonly found in
A.	low acid foods
B.	medium acid foods
C.	high acid foods
D.	any of these
Answer» B. medium acid foods

3.	Heat can travel only
A.	Upwards
B.	Downwards
C.	Upwards and Downwards
D.	None of the mentioned
Answer» E.

4.	A cold body contains no heat. The statement is
A.	Correct
B.	Incorrect
C.	Always correct
D.	None of the mentioned
Answer» C. Always correct

6.	Two state are given as followingI: Heat is a substanceII: Heat is proportional to temperature
A.	Both I and II are correct
B.	Both I and II are incorrect
C.	Only I is correct
D.	Only II is correct
Answer» C. Only I is correct

7.	In a single pass counter-flow heat exchanger, air enters at 700 K and leaves at 400 K. water enters at 300 K and leave at 600 K. Find the LMTD for the heat exchanger.
A.	144 K
B.	200 K
C.	100 K
D.	150 K
Answer» D. 150 K

8.	For what purpose annealing is done.
A.	Softness
B.	Hardness
C.	Toughness
D.	Ductility
Answer» B. Hardness

9.	______ is not a type of heat exchanger flow.A. Cross flowB. Counter flowC. Parallel flowD. Consecutive flow
A.	A
B.	B
C.	C
D.	D
Answer» E.

10.	A double pipe (shell and tube) heat exchanger is constructed of a stainless steel inner tube of inner diameter is 1.5 cm (Di) and outer diameter is (1.9 cm) The thermal resistance of the heat exchanger/unit length as 0.0532°C/W. determine the overall heat transfer co-efficient for the inner and outer surface area of the tube respectively.
A.	350 and 450 W/m2°C
B.	399 and 315 W/m2°C
C.	299 and 215 W/m2°C
D.	350 and 315 W/m2°C
Answer» C. 299 and 215 W/m2°C

11.	Hot shortness is a phenomenon of:
A.	hardening of nonferrous metals
B.	annealing of nonferrous metals
C.	annealing of ferrous metals
D.	hardening of ferrous metals
Answer» C. annealing of ferrous metals

12.	If one of the two fluids flowing through a heat exchanger of NTU = 2 remains at constant temperature throughout the exchanger length, the effectiveness of the heat exchanger will be
A.	1 – e-4
B.	1 – e-2
C.	\(\dfrac{{1 - {e^{ - 2}}}}{2}\)
D.	\(\dfrac{{1 - {e^2}}}{2}\)
Answer» C. \(\dfrac{{1 - {e^{ - 2}}}}{2}\)

17.	In heat exchanger, 50 kg of water is heater per minute from 50°C to 110°C by hot gases which enter the heat exchanger at 250°C. The value of Cp for water is 4.186 kJ/kg.K and for air is 1 kJ/kg.K. If the flow rate of gases is 100 kg/min, the net change of enthalpy of air will be nearly
A.	17.6 MJ/min
B.	15.0 MJ/min
C.	12.6 MJ/min
D.	10.0 MJ/min
Answer» D. 10.0 MJ/min

21.	Case hardening is done on mild steel by _____ process.
A.	normalizing
B.	hardening
C.	annealing
D.	nitriding
Answer» E.

27.	A cross-flow type air heater has an area of 50 m2. The overall transfer coefficient is 100 W/m2 K; and heat capacity of the stream, be it hot or cold, is 1000 W/K. What is the NTU?
A.	500
B.	50
C.	5
D.	0.5
Answer» D. 0.5

28.	In general, which of the following is the medium used to harden the high speed steel?
A.	Soda water
B.	Water
C.	Oil
D.	Salt water solution
Answer» D. Salt water solution

13.	In a condenser of a power plant, the steam condenses at a temperature of 60o C. The cooling water enters at 30o C and leaves at 45o C. The logarithmic mean temperature difference (LMTD) of the condenser is
A.	16.2°C
B.	21.6°C
C.	30°C
D.	37.5°C
Answer» C. 30°C

14.	In a counter flow heat exchanger, the product of specific heat and mass flow rate is same for the hot and cold fluids. If NTU is equal to 0.5 then the effectiveness of the heat exchanger is
A.	1
B.	0.5
C.	0.33
D.	0.2
Answer» D. 0.2

15.	Hot gases enter a heat exchanger at 200°C and leave at 150°C. The cold air enters at 40°C and leaves at 140°C . The capacity ratio of the heat exchanger will be:
A.	0.4
B.	0.45
C.	0.5
D.	0.52
Answer» D. 0.52

18.	In a counterflow heat exchanger, hot fluid enters at 60°C and cold fluid leaves at 30°C. Mass flow rate of the hot fluid is 1 kg/s and that of the cold fluid is 2 kg/s. Specific heat of the hot fluid is 10 kJ/kgK and that of the cold fluid is 5 kJ/kgK. The Log Mean Temperature Difference (LMTD) for the heat exchanger in ºC is
A.	15
B.	30
C.	35
D.	45
Answer» C. 35

19.	Air is cooled from 80 °C to 50 °C in a cooler. The coolant temperature rises from 30°C to 40°C. The LMTD value is 26°C. Find the type of heat exchanger.
A.	Cross Flow
B.	Double Flow
C.	Parallel Flow
D.	Counter Flow
Answer» B. Double Flow

20.	A balanced counter flow heat exchanger has a surface area of 20 m2 and overall heat transfer coefficient of 20 W/m2–K. Air (CP = 1000 J/kg - K) entering at 0.4 kg/s and 280 K is to be preheated by the air leaving the system at 0.4 kg/s and 300 K. The outlet temperature (in K) of the heated air is ___
A.	290
B.	300
C.	320
D.	350
Answer» C. 320

22.	In certain heat exchanger, both the fluids have identical mass flow rate-specific heat product. The hot fluid enters at 76°C and leaves at 47°C and the cold fluid entering at 28°C leaves at 57°C. The effectiveness of the heat exchanger is
A.	0.16
B.	0.6
C.	0.72
D.	1
Answer» C. 0.72

23.	In a parallel flow heat exchanger, the NTU is calculated to be 2.5 The lowest possible effectiveness for this heat exchanger is,
A.	92%
B.	50%
C.	41%
D.	27%
Answer» C. 41%

25.	In heat exchangers, the degree of approach is defined as the difference between temperatures of
A.	Cold water inlet and outlet
B.	Hot medium inlet and outlet
C.	Hot medium outlet and cold water inlet
D.	Hot medium outlet and cold water outlet
Answer» D. Hot medium outlet and cold water outlet

26.	A cold liquid enters a counter flow heat exchanger at 15 deg at a rate of 8 kg/s. A hot stream of the same liquid enters the heat exchanger at 75 deg at 2 kg/s. Assuming the specific heat of the fluid as 4 kJ/kg.°C, determine the maximum heat transfer rate.
A.	960 kW
B.	240 kW
C.	1920 kW
D.	480 kW
Answer» E.

Explore topic-wise MCQs in Chemical Process Calculation.

Canned poultry is more often spoiled by

Sulfur stinker spoilage, caused by is uncommonly found in

Heat can travel only

A cold body contains no heat. The statement is

Two state are given as followingI: Heat is a substanceII: Heat is proportional to temperature

In a single pass counter-flow heat exchanger, air enters at 700 K and leaves at 400 K. water enters at 300 K and leave at 600 K. Find the LMTD for the heat exchanger.

For what purpose annealing is done.

______ is not a type of heat exchanger flow.A. Cross flowB. Counter flowC. Parallel flowD. Consecutive flow

Hot shortness is a phenomenon of:

If one of the two fluids flowing through a heat exchanger of NTU = 2 remains at constant temperature throughout the exchanger length, the effectiveness of the heat exchanger will be

In a condenser of a power plant, the steam condenses at a temperature of 60o C. The cooling water enters at 30o C and leaves at 45o C. The logarithmic mean temperature difference (LMTD) of the condenser is

In a counter flow heat exchanger, the product of specific heat and mass flow rate is same for the hot and cold fluids. If NTU is equal to 0.5 then the effectiveness of the heat exchanger is

Hot gases enter a heat exchanger at 200°C and leave at 150°C. The cold air enters at 40°C and leaves at 140°C . The capacity ratio of the heat exchanger will be:

Heat treatment of metal is necessary

In heat exchanger, 50 kg of water is heater per minute from 50°C to 110°C by hot gases which enter the heat exchanger at 250°C. The value of Cp for water is 4.186 kJ/kg.K and for air is 1 kJ/kg.K. If the flow rate of gases is 100 kg/min, the net change of enthalpy of air will be nearly

Air is cooled from 80 °C to 50 °C in a cooler. The coolant temperature rises from 30°C to 40°C. The LMTD value is 26°C. Find the type of heat exchanger.

Case hardening is done on mild steel by _____ process.

In certain heat exchanger, both the fluids have identical mass flow rate-specific heat product. The hot fluid enters at 76°C and leaves at 47°C and the cold fluid entering at 28°C leaves at 57°C. The effectiveness of the heat exchanger is

In a parallel flow heat exchanger, the NTU is calculated to be 2.5 The lowest possible effectiveness for this heat exchanger is,

For the same inlet and exit temperatures of the hot and cold fluids, the Log mean temperature difference (LMTD) is

In heat exchangers, the degree of approach is defined as the difference between temperatures of

A cold liquid enters a counter flow heat exchanger at 15 deg at a rate of 8 kg/s. A hot stream of the same liquid enters the heat exchanger at 75 deg at 2 kg/s. Assuming the specific heat of the fluid as 4 kJ/kg.°C, determine the maximum heat transfer rate.

A cross-flow type air heater has an area of 50 m2. The overall transfer coefficient is 100 W/m2 K; and heat capacity of the stream, be it hot or cold, is 1000 W/K. What is the NTU?

In general, which of the following is the medium used to harden the high speed steel?