Thermodynamics PYQs - Last 10 Years

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Practice 197 JEE Main Chemistry questions from Thermodynamics. Use the year-wise and type-wise breakdown to prioritize recent PYQs, then continue into the question list below.

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Last 10 Years Thermodynamics Questions

Showing 47 of 197 filtered questions.

1Thermodynamics

At constant volume, 4 mol of an ideal gas when
heated from 300 K to 500K changes its internal
energy by 5000 J. The molar heat capacity at
constant volume is _______.

INTEGER+4 / -02020

2Thermodynamics

For the reaction :
A(\(l\)) \(\to\) 2B(g)
\(\Delta U = 2.1\,kcal,\,\Delta S = 20\,cal\,{K^{ - 1}}\) at 300 K
Hence \(\Delta\)G in kcal is :

INTEGER+4 / -02020

3Thermodynamics

The standard heat of formation \(\left( {{\Delta _f}H_{298}^0} \right)\) of ethane (in kj/mol), if the heat of combustion of
ethane, hydrogen and graphite are - 1560, -393.5 and -286 Kj/mol, respectively is :

INTEGER+4 / -02020

4Thermodynamics

For a reaction,
4M(s) + nO2(g) \(\to\) 2M2On(s)
the free energy change is plotted as a function
of temperature. The temperature below which
the oxide is stable could be inferred from the
plot as the point at which :

5Thermodynamics

Lattice enthalpy and enthalpy of solution of NaCl are 788 kJ mol–1, and 4 kJ mol–1, respectively.
The hydration enthalpy of NaCl is :

6Thermodynamics

For a dimerization reaction,
2A(g) \(\to\) A2(g)
at 298 K, \(\Delta\)Uo
= –20 kJ mol–1, \(\Delta\)So
= –30
JK–1 mol–1, then the \(\Delta\)Go
will be _____ J.

INTEGER+4 / -02020

7Thermodynamics

For one mole of an ideal gas, which of these
statements must be true?
(a) U and H each depends only on temperature
(b) Compressibility factor z is not equal to 1
(c) CP, m – CV, m = R
(d) dU = CVdT for any process

8Thermodynamics

The process that is NOT endothermic in nature
is :

9Thermodynamics

Five moles of an ideal gas at 1 bar and 298 K
is expanded into vacuum to double the volume.
The work done is :

10Thermodynamics

The internal energy change (in J) When 90 g of
water undergoes complete evaporation at
100oC is ____________.
(Given : \(\Delta\)Hvap for water at 373 K = 41 kJ/mol,
R = 8.314 JK–1 mol–1)

INTEGER+4 / -02020

11Thermodynamics

The heat of combustion of ethanol into carbon
dioxide and water is – 327 kcal at constant
pressure. The heat evolved (in cal) at constant
volume and 27oC (if all gases behave ideally) is
(R = 2 cal mol–1 K–1) ________.

INTEGER+4 / -02020

12Thermodynamics

Consider the reversible isothermal expansion of an ideal gas in a closed system at two different temperatures T1 and T2 (T1 < T2). The correct graphical depiction of the dependence of work done (w) on the final volume (V) is :

13Thermodynamics

The entropy change associated with the conversion of 1 kg of ice at 273 K to water vapours at 383 K is :
(Specific heat of water liquid and water vapour are 4.2 kJ K\(-\)1 kg\(-\)1 and 2.0 kJ K\(-\)1 kg\(-\)1; heat of liquid fusion and vap...

14Thermodynamics

Among the following, the set of parameters that
represents path function, is :
(A) q + w
(B) q
(C) w
(D) H–TS

15Thermodynamics

During compression of a spring the work done
is 10kJ and 2kJ escaped to the surroundings as
heat. The change in internal energy, \(\Delta\)U(inkJ)
is :

16Thermodynamics

For silver, Cp(J K–1 mol–1) = 23 +0.01 T. If the temperature (T) of 3 moles of silver is raised from 300
K to 1000 K at 1 atm pressure, the value of \(\Delta H\) will be close to :

17Thermodynamics

Which one of the following equations does not correctly represent the first law of thermodynamics
for the given processes involving an ideal gas? (Assume non-expansion work is zero)

18Thermodynamics

5 moles of an ideal gas at 100 K are allowed
to undergo reversible compression till its
temperature becomes 200 K.
If CV = 28 JK–1mol–1, calculate \(\Delta\)U and \(\Delta\)pV for
this process. (R = 8.0 JK–1 mol–1]

19Thermodynamics

For diatomic ideal gas in a closed system, which of the following plots does not correctly describe the relation between various thermodynamic quantities?

20Thermodynamics

The combination of plots which does not represent isothermal expansion of an ideal gas is –

21Thermodynamics

Given
(i)  C (graphite) + O2(g) \(\to\) CO2(g); \(\Delta\)rH\(^\Theta\) = x kJ mol\(-\)1
(ii)  C(graphite) + \({1 \over 2}\)O2(g) \(\to\) CO(g); \(\Delta\)rH\(^\Theta\) = y kJ mol\(-\)1
(iii)  CO(g) + \({1 \over 2}\) O2(g) $$ \to $...

22Thermodynamics

An ideal gas is allowed to expand form 1 L to 10 L against a constant external pressure of I bar. The work
done in kJ is :

23Thermodynamics

Enthalpy of sublimation of iodine is 24 cal g–1
at 200 oC. If specific heat of I2(s) and l2 (vap) are 0.055 and
0.031 cal g–1K
–1
respectively, then enthalpy of sublimation of iodine at 250 oC in cal g–1
is :

24Thermodynamics

For the chemical reaction X \(\rightleftharpoons\) Y, the standard reaction Gibbs energy depends on temperature T (in K) as
\(\Delta\)rGo (in kJ mol–1) = 120 \(- {3 \over 8}\) T.
The major component of the reaction mixture at T is :

25Thermodynamics

Two blocks of the same metal having same mass and at temperature T1 and T2, respectively, are brought in contact with each other and allowed to attain thermal equilibrium at constant pressure. The change in entropy, \(\Delta\)S, for this p...

26Thermodynamics

For the equilibrium,
2H2O \(\rightleftharpoons\) H3O+ + OH\(-\), the value of \(\Delta\)Go at 298 K is approximately :

27Thermodynamics

The reaction, MgO(s) + C(s) \(\to\) Mg(s) + CO(g), for which \(\Delta\)rHo + 491.1 kJ mol–1 and \(\Delta\)rSo = 198.0 JK–1 mol–1, is not feasible at 298 K. Temperature above which reaciton will be feasible is :

28Thermodynamics

The standard reaction Gibbs energy for a chemical reaction at an absolute temperature T is given by
\(\Delta\)rGo = A – BT
Where A and B are non-zero constants. Which of the following is TRUE about this reaction?

29Thermodynamics

A process has \(\Delta\)H = 200 J mol–1 and \(\Delta\)S = 40 JK–1 mol–1. Out of the values given below, choose the minimum temperature above which the process will be spontaneous :

30Thermodynamics

An ideal gas undergoes isothermal compression from 5m3 to 1 m3 against a constant external pressure of 4 Nm–2. Heat released in this process is used to increase the temperature of 1 mole of Al. If molar heat capacity of Al is 24 J mol–1 K–...

31Thermodynamics

The process with negative entropy change is :

32Thermodynamics

A process will be spontaneous at all temperatures if :

33Thermodynamics

The difference between \(\Delta\)H and \(\Delta\)U (\(\Delta\)H – \(\Delta\)U), when the combustion of one mole of heptane(l) is carried
out at a temperature T, is equal to :

34Thermodynamics

For which of the following processes, \(\Delta\)S is negative ?

35Thermodynamics

At 320 K, a gas A2 is 20% dissociated to A(g). The standard free energy change at 320 K and 1 atm in J mol-1 is approximately : (R = 8.314 JK-1 mol-1; ln2 = 0.693; ln 3 = 1.098)

36Thermodynamics

An ideal gas undergoes a cyclic process as shown in Figure.
\(\Delta\)UBC = \(-\)5 kJ mol-1, qAB = \(2\) kJ mol-1, WAB = \(-\)5 kJ mol-1, WCA = 3 kJ mol-1. Heat absorbed by the system during process \(CA\) is :

37Thermodynamics

For which of the following reactions, \(\Delta\)H is equal to \(\Delta\)U?

38Thermodynamics

Given
(i) 2Fe2O3(s) \(\to\) 4Fe(s) + 3O2(g);
\(\Delta\)rGo = + 1487.0 kJ mol-1
(ii) 2CO(g) + O2(g) \(\to\) 2CO2(g);
\(\Delta\)rGo = \(-\) 514.4 kJ mol-1
Free energy change, \(\Delta\)rGo for the reaction 2Fe2O3(s) + 6CO(g) $$ \...

39Thermodynamics

\(\Delta\)fGo at 500 K for substance 'S' in liquid state and gaseous state are +100.7 kcl mol-1 and +103 kcal mol-1, respectively. Vapour pressure of liquid 'S' at 500 K is approximately equal to : ( R = 2 cal K-1 mol-1 )

40Thermodynamics

The combustion of benzene(l) gives CO2(g) and H2O(l). Given that heat of combustion of benzene at constant volume is –3263.9 kJ mol–1 at 25oC; heat of combustion (in kJ mol–1) of benzene at constant pressure will be :
(R = 8.314 JK–1 mol–1)...

41Thermodynamics

Which of the following lines correctly show the temperature dependence of equilibrium constant K, for an
exothermic reaction?

42Thermodynamics

An ideal gas undergoes isothermal expansion at constant pressure. During
the process :

43Thermodynamics

A gas undergoes change from state A to state B. In this process, the heat absorbed
and work done by the gas is 5 J and 8 J, respectively. Now gas is brought back to
A by another process during which 3 J of heat is evolved. In this reverse p...

44Thermodynamics

For a reaction, A(g) \(\to\) A(\(\ell\)); \(\Delta\)H= \(-\) 3RT.
The correct statement for the reaction is :

45Thermodynamics

The enthalpy change on freezing of 1 mol of water at 5oC to ice at −5oC is :
(Given \(\Delta\)fusH = 6 kJ mol\(-\)1 at 0oC,
Cp(H2O, \(\ell\) = 75.3J mol\(-\)1 K\(-\)1)
Cp(H2O s) =36.8 J mol\(-\)1 K\(-\)1)

46Thermodynamics

\(\Delta\)U is equal to :

47Thermodynamics

Given, \({C_{(graphite)}} + {O_2} \to C{O_2}(g)\);
\({\Delta _r}{H^o}\) = - 393.5 kJ mol-1
\({{\rm H}_2}(g)\) + \({1 \over 2}{O_2}(g)\)\(\to {{\rm H}_2}{\rm O}(l)\)
\({\Delta _r}{H^o}\) = - 285.8 kJ mol-1
\(C{O_2}(g)\) + $$2{{\rm H}_2}{\rm ...