MCQ – UNIT II –CHEMICAL THERMODYNAMICS
1. What temperature will have the same reading on Kelvin scale and also on Fahrenheit
scale ?
(a) –40o C
(b) 0o C
(c) 212o C
(d) 574o C
2. A temperature different of 25o Celsius is equivalent to temperature difference of:
(a) 25o Fahrenheit
(b) 45o Fahrenheit
(c) 77o Fahrenheit
(d) none of the above
3. A thermometer reads in oX. It shows boiling point of water as 130o x and the freezing
point of water as – 20oX. The temperature reading of this thermometer corresponding to
60oC will be:
(a) 110o x
(b) 90oX
(c) 70oX
(d) 60oX
4. A constant volume gas thermometer works on:
(a) the principle of Archimedes
(b) Charle’s law
(c) Boyle’s law
(d) Pascal’s law
5. One kg ice is mixed with one kg of stream. After thermal equilibrium, the temperature
of the mixture becomes:
(a) 0oC
(b) 50oC
(c) 85oC
(d) 100oC
6. The Coefficient of superficial expansion of a substance is approximately equals to:
(a) twice the linear expansion
(b) thrice the linear expansion
(c) twice the cubical expansion
(d) thrice the cubical expansion
7.The increase in volume per unit volume per unit degree rise of temperature is known as
coefficient of:
(a) linear expansion
(b) superficial expansion
(c) cubical expansion
(d) all of above
8. If the coefficient of linear expansion of a solid is 0.0009, its coefficient of volume
expansion is:
(a) 0.00003
(b) 0.00009
(c) 0.00018
(d) 0.00027
9. when ice melts under a given pressure it:
(a) contracts
(b) expands
(c) evaporates
(d) remains constants in volume
10. Ice floats in water in a beaker and the water level is upto the brim. As ice melts
completely, the water level.
(a) rises
(b) fails
(c) remains constant
(d) first increase and then decreases
11. Heat from the distant star reaches the earth because of :
(a) Conduction
(b) Convection
(c) Radiation
(d) Scattering
12. The radiation emitted by a perfectly black body is proportional to:
(a) temperature ideal gas scale
(b) square of the temperature on ideal gas scale
(c) fourth root of temperature on ideal gas scale
(d) fourth power of temperature on ideals gas scale
13. Four identical pieces of copper are painter with different types of paints. Which one
would you expect to lose heat most rapidly if they are all heated to the same temperature
and allowed to cool in vacuum?
(a) painted shiny black
(b) painted rough black
(c) painted shiny white
(d) painted rough white
14. Kirchhoff’s law states that the ratio of the emissive power to he absorptive power for
a given wavelength at a given temperature is :
(a) same for all bodies and equal to emissive power of black body
(b) different for all bodies
(c) equal to emissive power of white body
(d) equal to absorptive power of black body
15. When a solid is changed to a gas with out melting the process is called:
(a) Boiling
(b) Melting
(c) Sublimation
(d) Osmosis
16. The critical temperature is that temperature :
(a) at which the volume of the gas becomes zero
(b) at which the molecular motion stops
(c) at which a gas is converted into liquid state
(d) above which a gas cannot be liquefied by applying pressure alone
17. Velocity of the heat emitted from the wick of the candle is:
(a) equal to the velocity of electrons
(b) equal to the velocity of X-rays
(c) less than the velocity of light
(d) greater than the velocity of light
18. A larger glacier melts at the base but not at the top because:
(a) the base of the glacier remains in warmer surrounding
(b) ice at the base of glacier contains impurities
(c) due to high pressure ice at the base has its melting point lowered
(d) ice at the top is of different kind
19. A hot body cools from 90oC to 80oC in 5 minutes under the same external conditions.
The time taken by the body to cool from 80oC to 70oC will be:(a) equal to 5 minutes
(b) more than 5 minutes
(c) less than 5 minutes
(d) more than or less than 5 minutes depending upon the nature of the body
20. Food is cooked earlier in a pressure cooker because :
(a) pressure inside it remains constant
(b) no heat is lost
(c) boiling starts at lower temperature
(d) boiling starts at lower temperature
21. Density of water is maximum at
(a) 4oC
(b) 4oF
(c) 40K
(d) none of above
22. Expansion during heating:
(a) occurs only in gases
(b) decrease the density of a material
(c) increases the weight of the material
(d) occurs at the same rate for all substance
23. In an isothermal expansion of an ideal gas:
(a) pressure remains constant
(b) heat content remains constant
(c) temperature remains constant
(d) volume remains constant
24. 3000oK temperature can be measured accurately by:
(a) constant volume air thermometer
(b) thermocouple
(c) vapour pressure thermometer
(d) pyrometer
25. Mercury thermometers can be used to measure temperature approximately upto:
(a) 100oC
(b) 400oC
(c) 800oC
(d) 2000oC
26. Platinum resistance thermometer is based on the principle of :
(a) change in resistance with the change in temperature
(b) change in resistance with the change in volume
(c) change in resistance with the change in pressure
(d) constancy of resistance
27. A temperature degree on the Celsius scale is same as:
(a) a temperature degree on the Fahrenheit scale
(b) a temperature degree on the Reumur scale
(c) a temperature degree on the Kelvin scale
(d) all of above
28. The specific heat of a substance is defined as the amount of the heat required to raise:
(a) the temperature of the whole substance through 1Co at constant volume
(b) the temperature of the whole substance through 1Co at constant pressure.
(c) the temperature of the whole substance through 1Co
(d) the temperature of the one gm, of substance through 1Co
29. If P is the pressure and U is the internal energy then by definition.
(a) dU = dQ + PdV
(b) dU = dQ + VdP
(c) dU = dQ + P.dV
(d) dU = dQ + V.dP
30. The internal energy U is an unique function of any state because the change in U:
(a) does not depend upon the path
(b) depends upon the path
(c) corresponds to an adiabatic process
(d) corresponds to an isothermal process
31. Standard enthalpy of vapourisation DvapHQ for water at 100° C is 40.66 kJmol–1.
The internal energy of vapourisation of water at 100°C (in kJmol–1) is
(a)+43.76
(b)+40.66
(c)+37.56
(d)–43.76
32. The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the
melting of ice at 0°C is
(a) 5.260 cal/(mol K)
(b)0.526 cal/(mol K)
(c)10.52 cal/(mol K)
(d)21.04 cal/(mol K)
33. Consider the reaction 4NO2(g) + O2(g) ® 2N2O5(g), ΔrH = –111kJ. If N2O5(s) is
formed instead of N2O5(g) in the above reaction, the ΔrH value will be: (given, ΔH of
sublimation for N2O5 is 54 kJ mol–1) [
(a)–219 kJ
(b)–165 kJ
(c)+ 54 kJ
(d) + 219 kJ
34. Based on the first law of thermodynamics, which one of the following is correct?
(a) For an isothermal process, q = +w
(b)For an isochoric process, ΔU = -q
(c)For an adiabatic process, ΔU = -w
(d)For a cyclic process, q = -w
35. The amount of the heat released when 20 ml 0.5 M NaOH is mixed with 100 ml 0.1
M HCl is x kJ. The heat of neutralization is
(a) – 100 x kJ/mol
(b)– 50 x kJ/mol
(c)+ 100 x kJ/mol
(d)+50 x kJ/mol
36. The bond energy (in kcal mol–1) of a C—C single bond is approximately [IIT JEE
2010]
(a)1
(b)10
(c)100
(d)1000
37. The species which by definition has ZERO standard molar enthalpy of formation at
298 K is
(a) Br2(g)
(b)Cl2(g)
(c)H2O(g)
(d)CH4(g)
38. The standard enthalpy of formation of NH3 is –46.0 kJ mol–1. If the enthalpy of
formation of H2 from its atoms is –436 kJ mol–1 and that of N2 is –712 kJ mol–1, the
average bond enthalpy of N — H bond is NH3 is
(a) –1102 kJ mol–1
(b) –964 kJ mol–1
(c)+352 kJ mol–1
(d) +1056 kJ mol–1
39. The amount of heat evolved when 500 cm3 of 0.1 M HCl is mixed with 200 cm3 of
0.2 M NaOH is ______.
(a) 1.292 kJ
(b) 2.292 kJ
(c)3.392 kJ
(d)0.292 kJ
40. In a constant volume calorimeter, 3.5 g of a gas with molecular weight 28 was burnt
in excess oxygen at 298.0 K. The temperature of the calorimeter was found to increase
from 298.0 K to 298.45 K due to the combustion process. Given that the heat capacity of
the calorimeter is 2.5 kJ K−1, the numerical value for the enthalpy of combustion of the
gas in kJ mol−1 is [IIT JEE 2009]
(a) 3
(b) 7
(c)8
(d) 9
41. If one mole of ammonia and one mole of hydrogen chloride are mixed in a closed
container to form ammonium chloride gas, then [Karnataka CET 2008]
(a) ΔH > Δu
(b) ΔH = Δu
(c)ΔH < Δu
(d)there is no relationship
42. Which of the following is an intensive property? [Karnataka CET 2007]
(a) temperature
(b) surface tension
(c)viscosity
(d) all of these
43. An ideal gas is allowed to expand both reversibly and irreversibly in an isolated
system. If Ti is the initial temperature and Tf is the final temperature, which of the
following statements is correct?
(a) (Tf)irrev > (Tf)rev
(b)Tf > Ti for reversible process but Tf = Ti for irreversible process
(c)(Tf)rev = (Tf)irrev
(d)Tf = Ti for both reversible and irreversible processes
44.The standard enthalpy of formation (ΔfH°) at 298 K for methane, CH4(g), is –74.8 kJ
mol–1. The additional information required to determine the average energy for C – H
bond formation would be
(a)the dissociation energy of H2 and enthalpy of sublimation of carbon
(b)latent heat of vaporization of methane
(c)the first four ionization energies of carbon and electron gain enthalpy of hydrogen
(d) the dissociation energy of hydrogen molecule, H2
45 The temperature of the system .decreases in an ______.
(a)adiabatic compression
(b)isothermal expansion
(c)isothermal compression
(d)adiabatic expansion
46. Identify the correct statement from the following in a chemical reaction.
(a)The entropy always increases
(b)The change in entropy along with suitable change in enthalpy decides the fate of a
reaction
(c)The enthalpy always decreases
(d)Both the enthalpy and the entropy remain constant
47. For the reversible reaction, A(s) + B(g) C(g) + D(g) ΔG° = -350kJ, which one of the
following statements is true?
(a)The reaction is thermodynamically non-feasible.
(b)The entropy change is negative.
(c)Equilibrium constant is greater than one.
(d) The reaction should be instantaneous.
48.The enthalpy of vaporization of benzene is +35.3 kJ/mol at its boiling point of 80°C.
The entropy change in the transition of vapour to liquid at its boiling point is ______. (in
J mol−1 K−1)
(a)−100
(b)+100
(c)+342
(d)−342
49. The entropy change involved in the isothermal reversible expansion of 2 moles of an
ideal gas from a volume of 10 dm3 to a volume of 100 dm3 at 27°C is [AIEEE 2011]
(a) 42.3 J mol–1 K–1
(b)38.3 J mol–1 K–1
(c)35.8 J mol–1 K–1
(d) 32.3 J mol–1 K–1
50. In view of the signs of ΔrG° for the following reactions PbO2 + Pb → 2 PbO, ΔrG°
<0
SnO2 + Sn → 2 SnO, ΔrG° > 0,
Which oxidation states are more characteristic for lead and tin?
(a)For lead +2, for tin +4
(b) For lead +4, for tin +2
(c)For lead +2, for tin +2
(d)For lead +4, for tin +4
51.The Gibbs energy for the decomposition Al2O3 at 500°C is as follows:
Al2O3 → Al + O2, ΔrG = +966kJ mol–1
The potential difference needed for electrolytic reduction of Al2O3 at 500°C is at least
(a)5.0 V
(b)4.5 V
(c)3.0 V
(d)2.5 V
52.For a particular reversible reaction at temperature T, ΔH and ΔS were found to be both
+ve. If Te is the temperature at equilibrium, the reaction would be spontaneous when
(a)T = Te
(b)Te > T
(c)T > Te
(d)Te is 5 times T
53.On the basis of the following thermochemical data:
(ΔfG°H+(aq) = 0)
H2O(l) → H+ (aq) + OH− (aq); ΔH = 57.32 kJ
H2 (g) + O2(g) → H2O(l) ΔH = −286.20kJ
The value of enthalpy of formation of OH− ion at 25°C is :
(a)−22.88 kJ
(b)−228.88 kJ
(c)+228.88 kJ
(d)−343.52 kJ
54.In a fuel cell methanol is used as fuel and oxygen gas is used as an oxidizer. The
reaction is
CH3OH(l) + O2(g) → CO2(g) + 2H2O(l)
At 298 K standard Gibb's energies of formation for CH3OH(l), H2O(l) and CO2(g) are –
166.2, –237.2 and –394.4 kJ mol–1 respectively. If standard enthalpy of combustion of
methanol is –726 kJ mol–1, efficiency of the fuel cell will be
(a)87%
(b)90%
(c)97%
(d)80%
55.One mole of which of the following has the highest entropy?
(a)liquid nitrogen
(b)hydrogen gas
(c)mercury
(d)diamond
56.When compared to ΔG° for the formation of Al2O3, the ΔG° for the formation of
Cr2O3 is
(a)higher
(a)lower
(c)same
(d)unpredicted
57.Standard entropy of X2, Y2 and XY3 are 60, 40 and 50JK−1mol−1, respectively.
For the reaction, X2 + Y2 → XY3, ΔH = -30kJ, to be at equilibrium, the temperature will
be
(a)1250 K
(b)500 K
(c)750 K
(d)1000 K
58.Entropy of the universe is
(a)continuously increasing
(b)continuously decreasing
(c)zero
(d)constant
59.In which of the following process, a maximum increase in entropy is observed?
(a)dissolution of salt in water
(b)conde
(c)sublimation of naphthalene
(d)melting of ice
60.ΔHvap = 30 KJ/mole and ΔSvap = 75 Jmol–1K–1. Find temperature of vapour, at one
atmosphere
(a)400 K
(b)350 K
(c)298 K
(d)250 K
61.Answer the following questions and then press 'Submit' to get your score.
Which one of the following definitions best describes the concept of work?
(a) the flow of energy from one object or substance to another due to a difference in
temperature
(b) the flow of energy from one body to another through uniform molecular motion
(c) the force associated with molecular motion
(d) the random motion of molecules in a gas at low pressure
62.An isolated system is best described by which one of the following statements?
(a) Neither matter nor heat can pass into or out of the system
(b) The system has a boundary which allows heat to be transferred but does not allow
material to pass into or out of the system
(c) The system has a diathermic boundary
(d) A system which has reached thermal equilibrium with its surroundings
63.Which one of the following statements describes a path function?
(a) A property of a system that depends only on the current state of the system, not on the
path the system took to reach that state
(b) A property of a system that depends on the path taken between the initial and final
states
(c) The sum of kinetic and potential energy contained in a substance
(d) The heat energy absorbed by a system at constant pressure
64.Consider the following thermodynamic properties.
(a) work done on a system
(b) heat absorbed
(c) entropy
(d) enthalpy
65.Which of the following statements best describes the Second Law of
Thermodynamics?
(a) The internal energy of the universe is constant.
(b) Energy can be neither created nor destroyed.
(c) When an isolated system undergoes a spontaneous change, the entropy of the system
will increase.
(d) At absolute zero, the entropy of a perfect crystal is considered to be zero.
66.A drug used to treat hypertension undergoes a decomposition reaction to give an
insoluble product. Calculate the temperature at which this reaction becomes spontaneous
if the enthalpy of the reaction at 298 K is 51 kJ mol-1 and the entropy of the reaction at
this temperature is 118.74 J K-1 mol-1.
(a) 430 K
(b) 2 300 K
(c) 0.5 K
(d) 430oC
67.Which one of the following equations defines the enthalpy of reaction, ΔH, for a
reaction occurring at constant pressure that does expansion work? All terms have their
usual meanings.
(a) ΔH = ΔU
(b) ΔH = ΔU + pΔV
(c) ΔH = ΔG - TΔS
(d) ΔH = q + w
68.The combustion of methanol is described by the following equation:
CH3OH + O2 → CO2 + 2H2O
Use Hess's Law to calculate the enthalpy of combustion (ΔHC) of methanol given the
following standard enthalpies of formation (ΔHfθ ).
ΔHfθ methanol = - 238.0 kJ mol-1
ΔHfθ H2O = - 285.5 kJ mol-1
ΔHfθ CO2 = - 393.51 kJ mol-1
ΔHfθ O2 = 0 kJ mol-1
(a) -1203.2 kJ mol-1
(b) -441.35 kJ mol-1
(c) 727.2 kJ mol-1
(d) -727.2 kJ mol-1
69.Which of the following statements will always apply when a reversible chemical
reaction has attained equilibrium?
(a) All reactants will convert to products
(b) The reaction proceeds alternately in the forward and reverse directions
(c) The Gibbs free energy of the system reaches a minimum
(d) The forward reaction will dominate over the reverse reaction
70.Which one of the following is an expression of the van't Hoff equation?
(a) ln K = - ΔHθ / RT + ΔSθ /R
(b) ΔH(T2) = ΔH(T1) + ΔCp(T2 - T1)
(c) ΔGθ = ΔHθ - TΔSθ
(d) ΔU = q + w
71.Which one of the following thermodynamic quantities is not a state function?
(a) Gibbs free energy
(b) enthalpy
(c) entropy
(d) internal energy
(e) work
72.At a constant temperature, an ideal gas is compressed from 6.0 liters to 4.0 liters by a
constant external pressure of 5.0 atm. How much work is done on the gas?
(a) w = +10 liter atm
(b) w = -10 liter atm
(c) w = +30 liter atm
(d) w = -30 liter atm
(e) The answer cannot be calculated.
.73. A system suffers an increase in internal energy of 80 J and at the same time has 50 J
of work done on it. What is the heat change of the system?
(a) +130 J
(b) +30 J
(c) -130 J
(d) -30 J
(e) 0 J
74. A 5.000 g sample of methanol, CH3OH, was combusted in the presence of excess
oxygen in a bomb calorimeter conaining 4000 g of water. The temperature of the water
increased from 24.000 oC to 29.765 oC. The heat capacity of the calorimeter was 2657
J/oC. The specific heat of water is 4.184 J/goC. Calculate E for the reaction in kJ/mol.
(a) -314 kJ/mol
(b) -789 kJ/mol
(c) -716 kJ/mol
(d) -121 kJ/mol
(e) -69.5 kJ/mol
75. A coffee cup calorimeter having a heat capacity of 451 J/oC was used to measure the
heat evolved when 0.0300 mol of NaOH(s) was added to 1000 mL of 0.0300 M HNO3
initially at 23.000 oC. The temperature of the water rose to 23.639 oC. Calculate H (in
kJ/mol NaNO3) for this reaction. Assume the specific heat of the final solution is 4.18
J/goC; the density of each solution is 1.00 g/mL; and the addition of solid does not
appreciably affect the volume of the solution.
HNO3(aq) + NaOH(s) NaNO3(aq) + H2O(l)
(a) -63.7 kJ/mol
(b) -151 kJ/mol
(c) -2.55 kJ/mol
(d) -81.4 kJ/mol
(e) -98.6 kJ/mol
76. The Ho for the following reaction at 298 K is -36.4 kJ.
1/2 H2(g) + 1/2 Br2(l) HBr(g)
Calculate Eo at 298 K. The universal gas constant, R, is 8.314 J/mol K.
(a) -35.2 kJ
(b) +35.2 kJ
(c) -36.4 kJ
(d) -37.6 kJ
(e) +37.6 kJ
77. Calculate the amount of work done for the conversion of 1.00 mole of Ni to Ni(CO)4
in the reaction below, at 75oC. Assume that the gases are ideal. The value of R is 8.31
J/molK.
Ni(s) + 4 CO (g) Ni(CO)4(g)
(a) 1.80 x 103 J
(b) 8.68 x 103 J
(c) -1.80 x 103 J
(d) -8.68 x 103 J
(e) -494 J
78. All of the following have a standard heat of formation value of zero at 25oC and 1.0
atm except:
(a) N2(g)
(b) Fe(s)
(c) Ne(g)
(d) H(g)
(e) Hg(l)
79. For which of the following reactions would the Ho for the reaction be labeled Hfo?
(a) Al(s) + 3/2 H2(g) + 3/2 O2(g) Al(OH)3(s)
(b) PCl3(g) + 1/2 O2(g) POCl3(g)
(c) 1/2 N2O(g) + 1/4 O2(g) NO(g)
(d) CaO(s) + SO2(g) CaSO3(s)
(e) The Ho for all these reactions would be labeled Hfo.
80. Calculate Ho for the reaction:
Na2O(s) + SO3(g) Na2SO4(g) , given the following information:
(1) Na(s) + H2O(l) NaOH(s) + 1/2 H2(g)
-146 kJ
(2) Na2SO4(s) + H2O(l) 2NaOH(s) + SO3(g)+418 kJ
(3) 2Na2O(s) + 2H2(g) 4Na(s) + 2H2O(l)
+259 kJ
(a) +255 kJ
(b) -435 kJ
(c) -581 kJ
(d) +531 kJ
(e) -452 kJ
81. Calculate Hfo for the following reaction at 25.0 oC:
Fe3O4(s)+CO(g)
Hfo (kJ/mol) -1118
(a) -263 kJ
(b) 54 kJ
3FeO(s)
-110.5
+CO2(g)
-272
-393.5
(c) 19 kJ
(d) -50 kJ
(e) 109 kJ
82. Calculate the standard heat of formation, Hfo, for FeS2(s), given the following
information:
2FeS2(s) + 5O2(g) 2FeO(s) + 4SO2(g)
Hfo= -1370 kJ
Hfo for SO2(g) = -297 kJ/mol
Hfo for FeO(s) = -268 kJ/mol
(a) -177 kJ
(b) -1550 kJ
(c) -774 kJ
(d) -686 kJ
(e) +808 kJ
83. Estimate the heat of reaction at 298 K for the reaction shown, given the average bond
energies below.
Br2(g) + 3F2(g) 2BrF3(g)
Bond
Bond Energy
Br-Br
192 kJ
F-F
158 kJ
Br-F
197 kJ
(a) -516 kJ
(b) -410 kJ
(c) -611 kJ
(d) -665 kJ
(e) -720 KJ
84. What is the standard entropy change of the reaction below at 298 K with each
compound at the standard pressure?
N2(g) +
3H2(g) gives 2NH3(g)
So298 (J/mol K)
191.5
130.6
192.3
(a) -198.7 J/K
(b) 76.32 J/K
(c) 303.2 J/K
(d) -129.7 J/K
(e) 384.7 J/K
85. The entropy will usually increase when
I. a molecule is broken into two or more smaller molecules.
II. a reaction occurs that results in an increase in the number of moles of gas.
III. a solid changes to a liquid.
IV. a liquid changes to a gas.
(a) I only
(b) II only
(c) III only
(d) IV only
(e) I, II, III, and IV
86. Calculate Go for the reaction given the following information:
2SO2(g) + O2(g) 2SO3(g)
Gfo for SO2(g) = -300.4 kJ/mol
Gfo for SO3(g) = -370.4 kJ/mol
(a) -70.0 kJ
(b) +70.0 kJ
(c) -670.8 kJ
(d) -140.0 kJ
(e) +140.0 kJ
87. For the following reaction at 25oC, Ho = +115 kJ and So = +125 J/K. Calculate Go
for the reaction at 25o.
SBr4(g) S(g) + 2Br2(l)
(a) +152 kJ
(b) -56.7 kJ
(c) +77.8 kJ
(d) +37.1 kJ
(e) -86.2 kJ
88. The heat of vaporization of freon, CCl2F2, is 17.2 kJ/mol at 25oC. What is the
change of entropy for one mole of liquid freon when it vaporizes at 25oC? (Hint: The
vaporization process is at equilibrium and what is true for G at equilibrium?)
(a) 57.7 J/K
(b) 0.688 J/K
(c) 5.13 x 103 kJ/K
(d) 3.16 J/K
(e) 239 J/K
89. Estimate the boiling point of Br2(l) (H = 30.9 kJ; S = 93.0 J/K).
Br2(l) Br2(g)
(a) 85oC
(b) 373oC
(c) 177oC
(d) 59oC
(e) 44oC
90. For the reaction, A + B C, Ho = +30 kJ; So = +50 J/K.
Therefore the reaction is:
(a) spontaneous at all temperatures.
(b) nonspontaneous at all temperatures.
(c) spontaneous at temperatures less than 600 K.
(d) spontaneous at temperatures greater than 600 K.
(e) spontaneous only at 25oC.
91. How much heat is absorbed in the complete reaction of 3.00 grams of SiO2 with
excess carbon in the reaction below? Ho for the reaction is +624.7 kJ.
SiO2(s) + 3C(s) SiC(s) + 2CO(g)
(a) 366 kJ
(b) 1.13 x 105 kJ
(c) 5.06 kJ
(d) 1.33 x 104 kJ
(e) 31.2 kJ
92. The standard heat of combustion of ethanol, C2H5OH, is 1372 kJ/mol ethanol. How
much heat (in kJ) would be liberated by completely burning a 20.0 g sample?
(a) 686 kJ
(b) 519 kJ
(c) 715 kJ
(d) 597 kJ
(e) 469 kJ
93. Which statement is incorrect?
(a) At constant pressure, H = E + PV
(b) The thermodynamic symbol for entropy is S.
(c) Gibbs free energy is a state function.
(d) For an endothermic process, H is negative.
(e) If the work done by the system is greater than the heat absorbed by the system, E is
negative.
94. Which statement is false?
(a) The thermodynamic quantity most easily measured in a "coffee cup" calorimeter is H.
(b) No work is done in a reaction occurring in a bomb calorimeter.
(c) H is sometimes exactly equal to E.
(d) H is often nearly equal to E.
(e) H is equal to E for the reaction:
95. According to first law of thermodynamics
(a) Total internal energy of a system during a process remains constant
(b) Total energy of a system remains constant
(c) Work done by a system is equal to the heat transferred by the system
(d) None of the above
96. The measurement of a thermodynamics property known as temperature is based on
(a) Zeroth law of thermodynamics
(b) First law of thermodynamics
(c) Second law of thermodynamics
(d) None of the above
97. Which of the following is correct?
(a). Absolute pressure = Gauge pressure + Atmospheric pressure
(b). Gauge pressure = Absolute pressure + Atmospheric pressure
(c). Atmospheric pressure = Gauge pressure + Absolute pressure
(d). None of the above
98. A mixture of gas expands from 0.03m3 to 0.06m3 at a constant pressure of 1 MPa and
absorbs 84 k J of heat during the process. The change in internal energy of the mixture is
(a). 30 k J
(b). 54 k J
(c). 84 k J
(d). None of the above
99. For the constant pressure and heat input, the air standard efficiency of gas power
cycle is in the order
(a). Dual cycle, Diesel cycle, Otto cycle
(b). Otto cycle, Diesel cycle, Dual cycle
(c). Dual cycle, Otto cycle, Diesel cycle
(d). None of the above
100. An open cycle gas turbine works on
(a). Carnot cycle
(b). Otto cycle
(c). Joule’s cycle
(d). None of the above
101. If all the variables of a stream are independent of time it is said to be in
(a) steady flow
(b) unsteady flow
(c) uniform flow
(d) closed flow
(e) constant flow.
102. A control volume refers to
(a) a fixed region in space
(b) a specified mass
(c) an isolated system
(d) a reversible process only
(e) a closed system.
103. Internal energy of a perfect gas depends on
(a) temperature, specific heats and pressure
(b) temperature, specific heats and enthalpy
(c) temperature, specific heats and entropy
(d) temperature only.
104. In reversible polytropic process
(a) true heat transfer occurs
(b) the entropy remains constant
(c) the enthalpy remains constant
(d) the internal energy remains constant
(e) the temperature remains constant.
105. An isentropic process is always
(a) irreversible and adiabatic
(b) reversible and isothermal
(c) frictionless and irreversible
(d) reversible and adiabatic
(e) none of the above.
106. In the polytropic process equation pvn = constant, if n is infinitely large, the
process is termed as
(a) constant volume
(b) constant pressure
(c) constant temperature
(d) adiabatic
(e) isothermal.
107. Steady flow occurs when
(a) conditions do not change with time at any point
(b) conditions are the same at adjacent points at any instant
(c) conditions change steadily with the time
(d) none of these
108. A reversible process requires that
(a) there be no heat transfer
(b) Newton’s law of viscosity be satisfied
(c) temperature of system and surroundings be equal
(d) there be no viscous or coulomb friction in the system
(e) heat transfer occurs from surroundings to system only.
109. The first law of thermodynamics for steady flow
(a) accounts for all energy entering and leaving a control volume
(b) is an energy balance for a specified mass of fluid
(c) is an expression of the conservation of linear momentum
(d) is primarily concerned with heat transfer
(e) is restricted in its application to perfect gases.
110. The characteristic equation of gases pV = mRT holds good for
(a) monoatomic gases
(b) diatomic gas
(c) real gases
(d) ideal gases
(e) mixture of gases.
111. A gas which obeys kinetic theory perfectly is known as
(a) monoatomic gas
(b) diatomic gas
(c) real gas
(d) pure gas
(e) perfect gas.
112. Work done in a free expansion process is
(a) zero
(b) minimum
(c) maximum
(d) positive
(e) negative.
113. Which of the following is not a property of the system ?
(a) Temperature
(b) Pressure
(c) Specific volume
(d) Heat
(e) None of the above.
114 In the polytropic process equation pvn = constant, if n = 0, the process is termed as
(a) constant volume
(b) constant pressure
(c) constant temperature
(d) adiabatic
(e) isothermal.
115.The processes or systems that do not involve heat are called
(a) isothermal processes
(b) equilibrium processes
(c) thermal processes
(d) steady processes
(e) adiabatic processes.
116. The specific heat at constant volume is
(a). the amount of heat required to raise the temperature of unit mass of gas through one
degree, at constant volume
(b). the amount of heat required to raise the temperature of unit mass of gas through one
degree, at constant pressure
(c). the amount of heat required to raise the temperature of 1 kg of water through one
degree
(d). any one of the above
116. Those substances which have so far not been resolved by any means into other
substances of simpler form are called
(a) compounds
(b). molecules
(c). elements
(d). atoms
117. The area under the temperature-entropy curve (T – s curve) of any thermodynamic
process represents
(a) heat absorbed
(b). either heat absorbed or heat rejected
(c). none of these
(d). heat rejected
118. The efficiency of Diesel cycle depends upon
(a) temperature limits
(b) pressure ratio
(c) compression ratio
(d) cut-off ratio and compression ratio
119. Coke is produced
(a) from the finely ground coal by moulding under pressure with or without a binding
material
(b) when coal is first dried and then crushed to a fine powder by pulverising machine
(c) when coal is strongly heated continuously for 42 to 48 hours in the absence of air in a
closed vessel
(d) by heating wood with a limited supply of air to a temperature not less than 280°C
120. In an irreversible process, there is a
(a) gain of heat
(b) no gain of heat
(c) no loss of heat
(d) loss of heat
120. Kelvin-Planck’s law deals with
(a) conservation of heat
(b) conservation of work
(c) conversion of heat into work
(d) conversion of work into heat
121.The compression ratio for Diesel engines is
(a) 3 to 6
(b) 5 to 8
(c) 20 to 30
(d) 15 to 20
122. The gas constant (R) is equal to the __________ of two specific heats.
(a) sum
(b) difference
(c) product
(d) ratio
123. In an isothermal process
(a) there is no change in internal energy
(b) all of these
(c) there is no change in temperature
(d) there is no change in enthalpy
124. Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression
ratio and heat input because in Otto cycle
(a) combustion is at constant volume
(b) maximum temperature is higher
(c) heat rejection is lower
(d) expansion and compression are isentropic
125. Otto cycle is also known as
(a) constant volume cycle
(b) constant pressure cycle
(c) constant temperature and pressure cycle
(d) constant temperature cycle
126. Producer gas is obtained by
(a) carbonisation of bituminous coal
(b) passing steam over incandescent coke
(c) partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam
blast
(d) passing air and a large amount of steam over waste coal at about 650°C
127. The measurement of a thermodynamic property known as temperature is based on
(a) First law of thermodynamics
(b) none of these
(c) Zeroth law of thermodynamics
(d) Second law of thermodynamics
128. When two bodies are in thermal equilibrium with a third body, they are also in
thermal equilibrium with each other. This statement is called
(a) Second law of thermodynamics
(b) Kelvin Planck's law
(c) Zeroth law of thermodynamics
(d) First law of thermodynamics
129. For the same compression ratio, the efficiency of dual combustion cycle is
(a) less than Diesel cycle and greater than Otto cycle
(b) greater than Diesel cycle and less than Otto cycle
(c) less than Diesel cycle
(d) greater than Diesel cycle
130. For a perfect gas, according to Boyle’s law (where p = Absolute pressure, v =
Volume, and T = Absolute temperature)
(a) v/T = constant, if p is kept constant
(b) p v = constant, if T is kept constant
(c) p/T = constant, if v is kept constant
(d) T/p = constant, if v is kept constant
131. One kg of carbon produces __________ kg of carbon dioxide.
(a) 11/7
(b) 3/7
(c) 11/3
(d) 4/11
132. Which of the following is the correct statement of the second law of
thermodynamics?
(a) It is impossible to transfer heat from a body at a lower temperature to a higher
temperature, without the aid of an external source.
(b) There is a definite amount of mechanical energy, which can be obtained from a given
quantity of heat energy.
(c) It is impossible to construct an engine working on a cyclic process, whose sole
purpose is to convert heat energy into work.
(d) all of the above
133. A mixture of gas expands from 0.03 m3 to 0.06 m3 at a constant pressure of 1 MPa
and absorbs 84 kJ of heat during the process. The change in internal energy of the
mixture is
(a) 30 kJ
(b) 84 kJ
(c) 54 kJ
(d) 114 kJ
134. An adiabatic process is one in which
(a) the temperature of the gas changes
(b) no heat enters or leaves the gas
(c) all of the above
(d) the change in internal energy is equal to the mechanical workdone
135. The efficiency of Diesel cycle increases with
(a) constant cut-off
(b) none of these
(c) decrease in cut-off
(d) increase in cut-off
136. The distillation carried out in such a way that the liquid with the lowest boiling point
is first evaporated and recondensed, then the liquid with the next higher boiling point is
then evaporated and recondensed, and so on until all the available liquid fuels are
separately recovered in the sequence of their boiling points. Such a process is called
(a) full distillation
(b) carbonisation
(c) cracking
(d) fractional distillation
137. Workdone in a free expansion process is
(a) maximum
(b) minimum
(c) zero
(d) positive
138. A cycle consisting of one constant pressure, one constant volume and two isentropic
processes is known as
(a) Carnot cycle
(b) Stirling cycle
(c) Diesel cycle
(d) Otto cycle
139. Which of the following gas is mostly used in town for street and domestic lighting
and heating?
(a) Producer gas
(b) Coke oven gas
(c) Mond gas
(d) Coal gas
140. Which of the following is correct?
(a) Absolute pressure = Gauge pressure - Atmospheric pressure
(b) Absolute pressure = Gauge pressure + Atmospheric pressure
(c) Gauge pressure = Absolute pressure + Atmospheric pressure
(d) Atmospheric pressure = Absolute pressure + Gauge pressure
141. The efficiency of Diesel cycle approaches to Otto cycle efficiency when
(a) cut-off is decreased
(b) cut-off is increased
(c) cut-off is constant
(d) cut-off is zero
142. The efficiency and work ratio of a simple gas turbine cycle are
(a) low
(b) high
(c) very low
(d) very high
143. The compression ratio for petrol engines is
(a) 15 to 30
(b) 3 to 6
(c) 10 to 20
(d) 5 to 8
145. The pressure exerted by an ideal gas is __________ of the kinetic energy of all the
molecules contained in a unit volume of gas.
(a) two-third
(b) one-half
(c) three-forth
(d) one-third
146. The pressure exerted by an ideal gas is __________ of the kinetic energy of all the
molecules contained in a unit volume of gas.
(a) two-third
(b) one-half
(c) three-forth
(d) one-third
147. The value of gas constant (R) in S. I. units is
(a) 0.287 J/kgK
(b) 2.87 J/kgK
(c) 28.7 J/kgK
(d) 287 J/kgK
148. The processes occuring in open system which permit the transfer of mass to and
from the system, are known as
(a) non-flow processes
(b) none of these
(c) flow processes
(d) adiabatic processes
149. The amount of heat required to raise the temperature of the unit mass of gas through
one degree at constant volume, is called
(a) specific heat at constant volume
(b) specific heat at constant pressure
(c) none of these
(d) kilo Joule
150. The absolute zero temperature is taken as
(a) 237°C
(b) -273°C
(c) -237°C
(d) 273°C
151.During which of the following process does heat rejection takes place in Carnot
cycle?
(a) Isothermal expansion
(b) Isentropic expansion
(c) Isothermal compression
(d) Isentropic compression
152. A process, in which the temperature of the working substance remains constant
during its expansion or compression, is called
(a) isothermal process
(b) hyperbolic process
(c) polytropic process
(d) adiabatic process
153. The efficiency of Joule cycle is
(a) less than Carnot cycle
(b) greater than Carnot cycle
(c) equal to Carnot cycle
(d) none of these
154. The hyperbolic pocess is governed by
(a) Boyle's law
(b) Gay-Lussac law
(c) Charles' law
(d) Avogadro's law
155. The sum of internal energy (U) and the product of pressure and volume (p.v) is
known as
(a) enthalpy
(b) workdone
(c) entropy
(d) none of these
156. Stirling and Ericsson cycles are
(a) reversible cycles
(b) quasi-static cycles
(c) irreversible cycles
(d) semi-reversible cycles
157. Which is the incorrect statement about Carnot cycle?
(a) All the heat engines are based on Carnot cycle.
(b) It is used as the alternate standard of comparison of all heat engines.
(c) It provides concept of maximising work output between the two temperature limits.
(d) all of the above
158. An isothermal process is governed by
(a) Boyle's law
(b) Charles' law
(c) Gay-Lussac law
(d) Avogadro's law
159. When cut-off ratio is __________ the efficiency of Diesel cycle approaches to Otto
cycle efficiency.
(a) zero
(b) 1/4
(c) 1/5
(d) 2
160. The entropy of water at 0°C is assumed to be
(a) -1
(b) 1
(c) 2
(d) 0
161. The behaviour of a perfect gas, undergoing any change in the variables which
control physical properties, is governed by
(a) Charles' law
(b) Boyle's law
(c) Gay-Lussac law
(d) all of these
162. The total energy of a molecule is shared equally by the various degrees of freedom
possessed by it. This law is known as
(a) law of equipartition of energy
(b) none of these
(c) law of conservation of energy
(d) law of degradation of energy
163. According to Kelvin-Planck’s statement of second law of thermodynamics,
(a) it is impossible to construct a device which operates in a cyclic process and produces
no effect other than the transfer of heat from a cold body to a hot body
(b) it is impossible to construct an engine working on a cyclic process, whose sole
purpose is to convert heat energy into work
(c) it is possible to construct an engine working on a cyclic process, whose sole purpose
is to convert heat energy into work
(d) none of the above
164. A series of operations, which takes place in a certain order and restore the initial
conditions at the end, is known as
(a)irreversible cycle
(b) reversible cycle
(c) thermodynamic cycle
(d) none of these
165. The main cause for the irreversibility is
(a) heat transfer with a finite temperature difference
(b) unrestricted expansion
(c) mechanical and fluid friction
(d) all of the above
166. The gas turbine cycle with regenerator improves
(a) work ratio
(b) thermal efficiency
(c) avoids pollution
(d) none of these
167. The efficiency of Carnot cycle depends upon
(a) volume compression ratio
(b) pressure ratio
(c) temperature limits
(d) cut-off ratio and compression ratio
168. Which of the following is an intensive property of a thermodynamic system?
(a) Energy
(b) Volume
(c) Temperature
(d) Mass
169. The state of a substance whose evaporation from its liquid state is complete, is
known as
(a) air
(b) vapour
(c) perfect gas
(d) steam
170. When a gas is heated, change takes place in
(a) volume
(b) pressure
(c) temperature
(D) all of these
171. The heat and mechanical energies are mutually convertible. This statement was
established by
(a) Joule
(b) Boyle
(c) none of these
(d) Charles
172. The condition for the reversibility of a cycle is
(a) all of the above
(b) all the processes, taking place in the cycle of operation, must be extremely slow
(c) the pressure and temperature of the working substance must not differ, appreciably,
from those of the surroundings at any stage in the process
(d) the working parts of the engine must be friction free
173. The compression ratio is the ratio of
(a) swept volume to total volume
(b) swept volume to clearance volume
(c) total volume to clearance volume
(d) total volume to swept volume
174. In open cycle gas turbine plants
(a) a condenser is used
(b) the indirect heat exchanger and cooler is avoided
(c) all of the above
(d) direct combustion system is used
175. The volumetric or molar specific heat at constant pressure is the product of
(a) molecular mass of the gas and the gas constant
(b) atomic mass of the gas and the gas constant
(c) molecular mass of the gas and the specific heat at constant volume
(d) none of the above
176. An open cycle gas turbine works on
(a) Joule's cycle
(b) Otto cycle
(c) Carnot cycle
(d) Stirling cycle
177. Maximum work that could be secured by expanding the gas over a given pressure
range is the __________ work.
(a) isothermal
(b)adiabatic
(c)isentropic
(d)none of these
178. Internal energy change of a system over one complete cycle in a cyclic process is
(a)zero
(b)+ve
(c)-ve
(d)dependent on the path
179. Entropy is a measure of the __________ of a system.
(a) disorder
(b) orderly behaviour
(c) temperature changes only
(d) none of these
180. A chemical reaction will occur spontaneously at constant pressure and temperature,
if the free energy is
(a) zero
(b) positive
(c)negative
(d)none of these
181. Fundamental principle of refrigeration is based on the __________ law of
thermodynamics.
(a) zeroth
(b) first
(c) second
(d) third
182. For a spontaneous process, free energy
(a) is zero
(b) increases
(c) decreases whereas the entropy increases
(d) entropy both decrease
183.Which of the following is not an intensive property ?
(a) Chemical potential
(b) Surface tension
(c) Heat capacity
(d) None of these
183. Measurement of thermodynamic property of temperature is facilitated by
__________ law of thermodynamics.
(a) 1st
(b) zeroth
(c) 3rd
(d) none of these
184. The theoretical minimum work required to separate one mole of a liquid mixture at 1
atm, containing 50 mole % each of n- heptane and n- octane into pure compounds each at
1 atm is
(a) -2 RT ln 0.5
(b) -RT ln 0.5
(c) 0.5 RT
(d) 2 RT
185. Entropy of an ideal gas depends upon its
(a) pressure
(b) temperature
(c) both (a) & (b)
(d) neither (a) nor (b)
186. Isobaric process means a constant process.
(a) temperature
(b) pressure
(c) volume
(d) entropy
187. No work is done by the system, when a reaction occurs at constant
(a) volume
(b) temperature
(c) pressure
(d) none of these
188. If the vapour pressure at two temperatures of a solid phase in equilibrium with its
liquid phase are known, then the latent heat of fusion can be calculated by the
(a) Maxwell's equation
(b) Clayperon-Claussius equation
(c) Van Laar equation
(d) Nernst Heat Theorem
189. "At the absolute zero temperature, the entropy of every perfectly crystalline
substance becomes zero". This follows from the
(a) third law of thermodynamics
(b) second law of thermodynamics
(c) Nernst heat theorem
(d) Maxwell's relations
190. During Joule-Thomson expansion of gases
(a) enthalpy remains constant.
(b) entropy remains constant.
(c) temperature remains constant.
(d) none of these.
191. In a reversible chemical reaction (where, Δx = number of moles of products-number
of moles of reactants )
(a) addition of inert gas favours the forward reaction, when Δx is positive.
(b) pressure has no effect on equilibrium, when Δn = 0.
(c) addition of inert gas has no effect on the equilibrium constant at constant volume for
any value of Δx (+ ve, - ve) or zero).
(d) all 'a', 'b' & 'c'.
192. Pick out the correct statement:
(a) In an isothermal system, irreversible work is more than reversible work.
(b) Under reversible conditions, the adiabatic work is less than isothermal work.
(c) Heat, work, enthalpy and entropy are all 'state functions'.
(d) Matter and energy can not be exchanged with the surroundings in a closed system.
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193. In any spontaneous process,
(a) only F decreases
(b) only A decreases
(c) both F and A decreases
(d) both F and A increase
194. The expression, , gives the free energy change
(a) with pressure changes at constant temperature.
(b) under reversible isothermal volume change.
(c) during heating of an ideal gas.
(d) during cooling of an ideal gas.
195. Compressibility factor for almost all the gases are approximately same at the same
(a) pressure and temperature.
(b) reduced pressure and reduced temperature.
(c) critical pressure and critical temperature.
(d) none of these.
196. Pick out the wrong statement.
(a) Activity co-efficient is dimensionless.
(c) In a mixture of ideal gases, the fugacity of a component is equal to the partial pressure
of the component.
(d) The fugacity co-efficient is zero for an ideal gas.
197. The co-efficient of performance (COP) of a refrigerating system, which is its index
of performance, is defined as the ratio of useful refrigeration to the net work. The units of
__________ and COP are the same.
(a) kinematic viscosity
(b) work
(c) temperature
(d) none of these
198. In jet refrigerators, the refrigerating fluid is practically always
(a) water
(b) ammonia
(c) freon
(d) brine
199. Water on heating from 1 to 4°C
(a) contracts
(b) expands
(c) has same volume
(d) may contract or expand
200. Pick out the correct statement.
(a) Compression ratio of an Otto engine is comparatively higher than a diesel engine.
(b) Efficiency of an Otto engine is higher than that of a diesel engine for the same
compression ratio.
(c) Otto engine efficiency decreases with the rise in compression ratio, due to decrease in
work produced per quantity of heat.
(d) Diesel engine normally operates at lower compression ratio than an Otto engine for an
equal output of work.