Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2017 Winter 4th Sem Old 140504 Fundamental Chemical Engineering Calculations And Stoichiometry Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE ? SEMESTER ? IV ? EXAMINATION ? WINTER 2017
Subject Code: 140504 Date: 29/11/2017
Subject Name: Fundamental Chemical Engineering Calculations & Stoichiometry
Time: 02.30PM 05.00PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Classify the material balance. Discuss the various methods involved for solving
material balance problems without chemical reactions.
07
(b) The gaseous reaction A ? 2B + C takes place isothermally in a constant
pressure reactor. Starting with a mixture of 75% A and 25% inerts (by volume),
in a specified time the volume doubles. Calculate the conversion achieved.
07
Q.2 (a) The diameter and height of a vertical cylindrical tank are 4 ft and 6 ft 6 inch
respectively. It is full up to 80% height with carbon tetrachloride, the density of
which is 1.6 kg/l. Find the mass in kilograms and pounds.
07
(b) The conductance of a fluid-flow system is defined as the volumetric flow rate,
referred to a pressure of one torr (133.322 Pa). For an orifice, the conductance
C can be computed from
3
89.2 /
T
C A ft s
M
?
Where A = area of opening, ft
2
; T = Temperature,
0
R; M = Molecular Weight
Convert the empirical equation into SI units.
07
OR
(b) Discuss about recycling and bypassing operations with their importance. 07
Q.3 (a) With a typical example, explain the terms: Conversion, Yield, Selectivity,
Limiting component and Excess component.
07
(b) Differentiate between: (i) Sensible heat and latent heat (ii) Endothermic and
exothermic reactions (iii) intensive property and extensive property.
07
OR
Q.3 (a) A gas mixture has following composition by volume: CH
4
: 40%, C
2
H
6
: 35%,
C
3
H
8
: 25%. Find the average molecular mass of the gas mixture. Also find the
density of mixture in kg/m
3
at STP.
07
(b) The average molecular mass of a flue gas sample is calculated by two different
engineers. One engineer uses the correct molecular mass of 28 for N
2
and
determines the average molecular mass to be 30.08, the other engineer, using an
incorrect value of 14, calculates the average molecular mass to be 18.74.
Calculate the volume % of N
2
in the flue gases. If the remaining components of
the flue gases are CO
2
and O
2
, calculate the volume % of each of them.
07
Q.4 (a) Find the heat that must be transferred to heat a mixture of 25 mol% N
2
and 75
mol% H
2
from 298 K to 473 K flowing at a rate of 1.5 kmol/h. Heat capacity
data: Cp (kJ/kmol.K) = a + bT + cT
2
+ dT
3
Gas a b ? 10
3
c ? 10
6
d ? 10
9
N
2
29.59 -5.41 13.18 -4.97
H
2
28.61 1.02 -0.15 0.77
07
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE ? SEMESTER ? IV ? EXAMINATION ? WINTER 2017
Subject Code: 140504 Date: 29/11/2017
Subject Name: Fundamental Chemical Engineering Calculations & Stoichiometry
Time: 02.30PM 05.00PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Classify the material balance. Discuss the various methods involved for solving
material balance problems without chemical reactions.
07
(b) The gaseous reaction A ? 2B + C takes place isothermally in a constant
pressure reactor. Starting with a mixture of 75% A and 25% inerts (by volume),
in a specified time the volume doubles. Calculate the conversion achieved.
07
Q.2 (a) The diameter and height of a vertical cylindrical tank are 4 ft and 6 ft 6 inch
respectively. It is full up to 80% height with carbon tetrachloride, the density of
which is 1.6 kg/l. Find the mass in kilograms and pounds.
07
(b) The conductance of a fluid-flow system is defined as the volumetric flow rate,
referred to a pressure of one torr (133.322 Pa). For an orifice, the conductance
C can be computed from
3
89.2 /
T
C A ft s
M
?
Where A = area of opening, ft
2
; T = Temperature,
0
R; M = Molecular Weight
Convert the empirical equation into SI units.
07
OR
(b) Discuss about recycling and bypassing operations with their importance. 07
Q.3 (a) With a typical example, explain the terms: Conversion, Yield, Selectivity,
Limiting component and Excess component.
07
(b) Differentiate between: (i) Sensible heat and latent heat (ii) Endothermic and
exothermic reactions (iii) intensive property and extensive property.
07
OR
Q.3 (a) A gas mixture has following composition by volume: CH
4
: 40%, C
2
H
6
: 35%,
C
3
H
8
: 25%. Find the average molecular mass of the gas mixture. Also find the
density of mixture in kg/m
3
at STP.
07
(b) The average molecular mass of a flue gas sample is calculated by two different
engineers. One engineer uses the correct molecular mass of 28 for N
2
and
determines the average molecular mass to be 30.08, the other engineer, using an
incorrect value of 14, calculates the average molecular mass to be 18.74.
Calculate the volume % of N
2
in the flue gases. If the remaining components of
the flue gases are CO
2
and O
2
, calculate the volume % of each of them.
07
Q.4 (a) Find the heat that must be transferred to heat a mixture of 25 mol% N
2
and 75
mol% H
2
from 298 K to 473 K flowing at a rate of 1.5 kmol/h. Heat capacity
data: Cp (kJ/kmol.K) = a + bT + cT
2
+ dT
3
Gas a b ? 10
3
c ? 10
6
d ? 10
9
N
2
29.59 -5.41 13.18 -4.97
H
2
28.61 1.02 -0.15 0.77
07
2
(b) What will be the composition of gases obtained by burning pure FeS
2
with 60%
excess air? Assume that the reaction proceeds in the following manner.
4FeS
2
(s) + 11O
2
(g) ? 2Fe
2
O
3
(s) + 8SO
2
(g)
07
OR
Q.4 (a) A spent lye sample contains 9.6% glycerol and 10.3% NaCl salt. It is
concentrated at the rate of 5000 kg/h in a double effect evaporator until the final
solution contains 80% glycerol and 6% salt. 45% glycerol is lost by entrainment.
All the percentage are by mass. Determine:
(i) the evaporation taken place in the system
(ii) the amount of salt crystallized out from the evaporator
07
(b) Pure methane is heated from 303K to 523K at atmospheric pressure. Calculate
the heat added per kmol of methane using the following Cp data.
Cp = a + bT + cT
2
+ dT
3
Where a = 19.2494, b ? 10
3
= 52.1135, c ? 10
6
= 11.973, d ? 10
9
= -11.3173
07
Q.5 (a) Define the following unit operations with suitable diagram and example:
distillation, crystallization and evaporation.
07
(b) Define the following terms with supporting equations: (i) Absolute humidity (ii)
Relative humidity (iii) Humid heat
07
OR
Q.5 (a) It is required to make 1000 kg mixed acid containing 60% H
2
SO
4
, 32% HNO
3
and 8% water by blending (i) spent acid containing 11.3% HNO
3
, 44.4% H
2
SO
4
and 44.3% H
2
O, (ii) aqueous 90% HNO
3
and (iii) aqueous 98% H
2
SO
4
. All
percentage are by weight. Calculate the quantities of each of the three acids
required for blending.
07
(b) The dry bulb temperature & dew point of ambient air were found to be 302 K &
291 K respectively. The barometer reads 100 kPa, calculate : a) the absolute
molal humidity, b) the absolute humidity, c) % RH, d) % saturation, e) humid
heat, and f) humid volume.
Data : Vapour pressure of water at 291 K = 2.0624 kPa
Vapour pressure of water at 302 K = 4.004 kPa
07
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This post was last modified on 20 February 2020