Chemical Engineering

Heat Capacity Equations

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Water having CP = 10 J/oC, is heated from 10oC to 50oC, what is the enthalpy change?
100 J
250 J
400 J
500 J
Explanation:
∆H = 10∫5010.dT = 10*40 = 400 J.
Question 2
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A mixture contains 20% SO2 with CP= 35 J/oC, 30% NO3 with CP = 20 J/oC and 50% CO2 with CP = 40 J/oC, what is the average CP of mixture?
12 J/oC
17 J/oC
25 J/oC
33 J/oC
Explanation:
Average CP = 0.2*35 + 0.3*20 + 0.5*40 = 7 + 6 + 20 = 33 J/oC.
Question 3
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Pass Ratio : 100%
A mixture contains 20% O2 with CP = 15 J/oC and 80% CO2 with CP = 20 J/oC, what is the average CP of mixture?
3 J/oC
9 J/oC
16 J/oC
19 J/oC
Explanation:
Average CP = 0.2*15 + 0.8*20 = 19 J/oC.
Question 4
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Pass Ratio : 100%
What is the value of CP – CV for ideal gases?
0
R/2
R
2R
Explanation:
For ideal gases CP = CV + R.
Question 5
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Pass Ratio : 100%
A mixture contains 30% Ar with CP = 30 J/oC, 30% N2 with CP = 20 J/oC and 40% CH4 with CP = 10 J/oC, what is the average CP of mixture?
7 J/oC
12 J/oC
19 J/oC
26 J/oC
Explanation:
Average CP = 0.3*30 + 0.3*20 + 0.4*10 = 19 J/oC.
Question 6
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Pass Ratio : 100%
A mixture contains 20% O2 with CP = 10 J/oC, 30% N2 with CP = 20 J/oC and 50% CO2 with CP= 40 J/oC, what is the average CP of mixture?
20 J/oC
28 J/oC
34 J/oC
42 J/oC
Explanation:
Average CP = 0.2*10 + 0.3*20 + 0.5*40 = 2 + 6 + 20 = 28 J/oC.
Question 7
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Pass Ratio : 100%
Steam having CP = 105 J/oC, is heated from 100oC to 104oC, what is the enthalpy change?
210 J
420 J
630 J
840 J
Explanation:
∆H = 100∫104105.dT = 105*4 = 420 J.
Question 8
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Pass Ratio : 100%
Cyclohexane having CP = 48 J/oC, is heated from 50oC to 55oC, what is the enthalpy change?
240 J
480 J
720 J
960 J
Explanation:
∆H = 50∫5548.dT = 48*5 = 240 J.
Question 9
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Pass Ratio : 100%
Liquid benzene having CP = 29 J/oC, is heated from 5oC to 10oC, what is the enthalpy change?
29 J
145 J
195 J
290 J
Explanation:
∆H = 5∫1029.dT = 29*5 = 145 J.
Question 10
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Pass Ratio : 100%
Ice having CP = 15 J/oC, is heated from -10oC to -4oC, what is the enthalpy change?
30 J
60 J
90 J
120 J
Explanation:
∆H = -10∫-415.dT = 15*6 = 90 J.