Engineering Chemistry Questions and Answers – Determination of Calorific Value of Solid and Non-Volatile Liquid Fuels – 2

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This set of Engineering Chemistry Question Paper focuses on “Determination of Calorific Value of Solid and Non-Volatile Liquid Fuels – 2”.

1. To calculate the calorific value of coal using bomb’s calorimeter, which of the following compound are formed after the bomb is removed from the calorimeter?
a) H2S and CO2
b) H2SO4 and HNO3
c) H2SO4 and NO2
d) SO2 and HNO3
View Answer

Answer: b
Explanation: Since the vapours of H2SO4 and HNO3 are formed during combustion of coal, that is why at last the amounts of H2SO4 and HNO3 are calculated to find the gross calorific value of the coal.
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2. Which of the following correction of bomb calorimeter is added to the observed raise in temperature?
a) Acid correction
b) Fuse wire correction
c) Cotton thread correction
d) Cooling correction
View Answer

Answer: d
Explanation: Cooling correction is the product of time taken for the calorimeter to cool(x) and the rate of cooling (dt),
Cooling correction (tc) = x.dt

3. On what basis does the acid correction is measured in bomb calorimeter?
a) Gases present in the bomb
b) Due to formation of the compound after adding water in the bomb
c) Due to the presence of excess oxygen
d) Due to the material of the bomb
View Answer

Answer: b
Explanation: When water is added to the bomb, the gases present in it forms acid, due to which some heat is liberated which is not obtainable in practical use, thus this heat liberated has to be deducted from the value so as to get the exact value of GCV.

4. How is the heat liberated in fuse wire correction?
a) By the breakage of fuse wire
b) Due to the material of fuse wire
c) Due to the ignition of fuse wire
d) Due to the length of fuse wire
View Answer

Answer: c
Explanation: When an electric current passes through the fuse wire, there is some heat liberated which is of no use of the bomb, so it has to be subtracted from the final value.
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5. For which of the following correction we should use a larger sample mass?
a) Fuse wire correction
b) Cotton thread correction
c) Cooling correction
d) Acid correction
View Answer

Answer: b
Explanation: This is because the cotton thread correction obtained is very small, due to which for small masses its value is negligible, therefore for calculating these corrections we should use larger mass sample.

6. In a bomb calorimeter experiment, following data was obtained: x = 0.85gm, W = 2.5kg, w = .5kg, observed rise in temperature = 2.25 0C, tA = 38.6 calories, tF = 6.8 calories, tT = 1.9 calories and tC = 0.05 0C. Calculate net calorific value if the coal contains 10 % hydrogen?
a) 7533.7 cal/gm
b) 5704.655 cal/gm
c) 8062 cal/gm
d) 8.062 cal/gm
View Answer

Answer: a
Explanation: From the formulae,
GCV = [(W+w){(T2 – T1) + tc} – (tA + tF + tT)]/x
GCV = 8062 cal/gm
NCV = GCV – (0.09×587×%H)
NCV = 7533.7 cal/gm.

7. Which of the following correction are obtained in the largest amount in bomb calorimeter?
a) Fuse wire correction
b) Acid correction
c) Cotton thread correction
d) Cooling correction
View Answer

Answer: b
Explanation: This is because the amount of heat liberated during the analysis if acid correction is maximum, which is why it has the largest value.
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8. The correct cotton thread used for firing the charge is calculated from the weight of wet cotton thread.
a) True
b) False
View Answer

Answer: b
Explanation: Dry cotton thread is used in calculating the calorific value of fuel in a bomb calorimeter.

9. Determine the water equivalent of the bomb calorimeter apparatus which gave following data during experiment: Weight of benzoic acid taken = 2.12 gm, Weight of water taken in calorimeter = 2.5kg, Initial temperature= 16.970, Final temperature = 18.650, Cooling correction = 0.035 0C, fuse wire correction = 20 calories and cotton thread correction = 2.2 calories? (Calorific value of benzoic acid=6324)
a) 7253.22 gm
b) 8366.50 gm
c) 7830.36 gm
d) 5330.36 gm
View Answer

Answer: d
Explanation: Heat evolved by benzoic acid = 13406.88 calories
Total amount of heat given to calorimeter = 13429.08 calories
Corrected rise in temperature = 1.715 0C
Total water equivalent = 13429.08/1.715 = 7830.36 gm
Water equivalent of calorimeter = 5330.36 gm.

Sanfoundry Global Education & Learning Series – Engineering Chemistry.

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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