Chemical Engineering Questions and Answers – Heat Capacity Equations

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This set of Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Heat Capacity Equations”.

1. Water having CP = 10 J/oC, is heated from 10oC to 50oC, what is the enthalpy change?
a) 100 J
b) 250 J
c) 400 J
d) 500 J
View answer

Answer: c
Explanation: ∆H = 105010.dT = 10*40 = 400 J.
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2. Liquid benzene having CP = 29 J/oC, is heated from 5oC to 10oC, what is the enthalpy change?
a) 29 J
b) 145 J
c) 195 J
d) 290 J
View answer

Answer: b
Explanation: ∆H = 51029.dT = 29*5 = 145 J.

3. Ice having CP = 15 J/oC, is heated from -10oC to -4oC, what is the enthalpy change?
a) 30 J
b) 60 J
c) 90 J
d) 120 J
View answer

Answer: c
Explanation: ∆H = -10-415.dT = 15*6 = 90 J.

4. Steam having CP = 105 J/oC, is heated from 100oC to 104oC, what is the enthalpy change?
a) 210 J
b) 420 J
c) 630 J
d) 840 J
View answer

Answer: b
Explanation: ∆H = 100104105.dT = 105*4 = 420 J.

5. Cyclohexane having CP = 48 J/oC, is heated from 50oC to 55oC, what is the enthalpy change?
a) 240 J
b) 480 J
c) 720 J
d) 960 J
View answer

Answer: a
Explanation: ∆H = 505548.dT = 48*5 = 240 J.
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6. What is the value of CP – CV for ideal gases?
a) 0
b) R/2
c) R
d) 2R
View answer

Answer: c
Explanation: For ideal gases CP = CV + R.

7. 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?
a) 3 J/oC
b) 9 J/oC
c) 16 J/oC
d) 19 J/oC
View answer

Answer: d
Explanation: Average CP = 0.2*15 + 0.8*20 = 19 J/oC.

8. 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?
a) 7 J/oC
b) 12 J/oC
c) 19 J/oC
d) 26 J/oC
View answer

Answer: c
Explanation: Average CP = 0.3*30 + 0.3*20 + 0.4*10 = 19 J/oC.

9. 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?
a) 20 J/oC
b) 28 J/oC
c) 34 J/oC
d) 42 J/oC
View answer

Answer: b
Explanation: Average CP = 0.2*10 + 0.3*20 + 0.5*40 = 2 + 6 + 20 = 28 J/oC.
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10. 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?
a) 12 J/oC
b) 17 J/oC
c) 25 J/oC
d) 33 J/oC
View answer

Answer: d
Explanation: Average CP = 0.2*35 + 0.3*20 + 0.5*40 = 7 + 6 + 20 = 33 J/oC.

11. Heat Capacity of CO2 is given by 12 + 3T + T2, what is the enthalpy change from 0oC to 6oC?
a) 169 J
b) 198 J
c) 244 J
d) 360 J
View answer

Answer: b
Explanation: ∆H = 06 (12 + 3T + T2).dT = 12*6 + 3*36/2 + 63/3 = 198 J.

12. Heat Capacity of water is given by 4 + T2, what is the enthalpy change from 0oC to 3oC?
a) 7 J
b) 14 J
c) 21 J
d) 32 J
View answer

Answer: c
Explanation: ∆H = 03 (4 + T2).dT = 4*3 + 33/3 = 21 J.

13. CP-T curve covers 10 J from 2oC to 10oC, what is the enthalpy change?
a) 10 J
b) 20 J
c) 80 J
d) 100 J
View answer

Answer: a
Explanation: Enthalpy change is the area covered under CP-T curve.
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14. CP-T curve of CO2 forms a rectangle of height 10 J/oC from 5oC to 10oC?
a) 10 J
b) 50 J
c) 100 J
d) 250 J
View answer

Answer: b
Explanation: Enthalpy change is the area covered under CP-T curve = Area of rectangle = 10*(10 – 5) = 50 J.

15. CP-T curve of H2 forms a rectangle of height 20 J/oC from 4oC to 5oC?
a) 20 J
b) 80 J
c) 100 J
d) 140 J
View answer

Answer: c
Explanation: Enthalpy change is the area covered under CP-T curve = Area of rectangle = 20*(5 – 4) = 20 J.

Sanfoundry Global Education & Learning Series – Basic Chemical Engineering.

To practice all areas of Basic Chemical Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn