JEE Questions for Chemistry Thermodynamics Quiz 2 - MCQExams.com

When a solid melts reversibly
  • H decreases
  • G increases
  • E decreases
  • S increases
Condition for spontaneity in an isothermal process is
  • ∆A + W < 0
  • ∆G + U < 0
  • ∆A + U < 0
  • ∆G - U < 0
In equilibrium state the value of ∆G is
  • zero
  • negative
  • positive
  • may be negative or positive
Entropy of the universe is
  • constant
  • zero
  • continuously decreasing
  • continuously increasing
If ∆G = 46.06 kcal / mol, Kp at 300 K is
  • 10 -33.33
  • 10 -23.03
  • 10 -50.12
  • 10 +33.33
For a reversible reaction, ∆system + ∆Ssurrounding is
  • ∞
  • zero
  • 1
  • 2
Which is a condition for spontaneous ?
  • ∆G < 0
  • ∆G = 0
  • ∆G > 0
  • ∆G ≥ 0
In evaporation of water ∆H and ∆S are
  • + , +
  • +, -
  • - , -
  • - , +
What are the units of entropy ?
  • cal K
  • cal K-1
  • cm K-1
  • cm K
In any chemical reaction, a quantity that decrease to a minimum is
  • free energy
  • entropy
  • temperature
  • enthalpy

Chemistry-Thermodynamics-8633.png
  • heating, cooling, heating, cooling
  • cooling, heating, cooling, heating
  • heating, cooling, cooling, heating
  • cooling, heating, heating, cooling

Chemistry-Thermodynamics-8634.png
  • K to L and L to M
  • L to M and N to K
  • L to M and M to N
  • M to N and N to K
A gas expands from a volume of 1m3 to a volume of 2m3 against an external pressure of 105 Nm-2. The work done by the gas will be
  • 102 kJ
  • 102 J
  • 103 J
  • 105 kJ
We believe in the laws of thermodynamics because they are
  • theoretical
  • derived based on mathematical analysis
  • empirical and nobody disproved
  • mere statements
Which one of the following is an exothermic reaction ?
  • N2 (g) + O2 (g)+ 180.8 kJ → 2NO(g )
  • N2 (g) + 3H2(g) - 92 kJ → 2NH3 (g)
  • C(g ) + H2O(g) → CO(g) + H2 (g) - 131.1kJ
  • C (graphite) + 2S(s) → CS2(l) - 91.9 kJ
Which of the following taking place in the blast furnace is endothermic ?

  • Chemistry-Thermodynamics-8636.png
  • 2)
    Chemistry-Thermodynamics-8637.png

  • Chemistry-Thermodynamics-8638.png

  • Chemistry-Thermodynamics-8639.png
Hess's law states that
  • the standard enthalpy of an overall reaction is the sum of the enthalpy changes in individual reactions
  • enthalpy of formation of a compound is same as the enthalpy of decomposition of the compound into constituent elements, but with opposite sign
  • at constant temperature the pressure of a gas is inversely proportional to its volume
  • the mass of a gas dissolved per litre of a solvent is proportional to the pressure of the gas in equilibrium with the solution.
A swimmer coming out from a pool is covered with a film of water weighing about 18 g. Calculate the internal energy of vaporisation at 100°C.
[ ∆ vap H ⊖ for water at 373 K = 40.66 kJ mol -1 ]
The correct option is
  • 35.67 kJ mol -1
  • 37.56 kJ mol -1
  • 36.57 kJ mol -1
  • 38.75 kJ mol -1

Chemistry-Thermodynamics-8641.png
  • 250 R
  • - 500 R
  • 500 R
  • -250 R

Chemistry-Thermodynamics-8643.png

  • Chemistry-Thermodynamics-8644.png
  • 2)
    Chemistry-Thermodynamics-8645.png

  • Chemistry-Thermodynamics-8646.png

  • Chemistry-Thermodynamics-8647.png

Chemistry-Thermodynamics-8649.png
  • 780.086 kcal
  • - 780.086 kcal
  • - 390.043 kcal
  • 390.043 kcal
A piston filled with 0.04 mole of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of 37.0°C. As it does so, it absorbs 208 J of heat. The values of q and W for the process will be
( R = 8.314 J / mol K, In 7.5 = 2.
  • q = + 208 J , W = - 208 J
  • q = - 208 J , W = - 208 J
  • q = - 208 J , W = + 208 J
  • q =+ 208 J , W =+ 208 J
Based on the first law of thermodynamics, which one of the following is correct ?
  • For an isochoric process = ∆E = - Q
  • For an adiabatic process = ∆E = - W
  • For an isothermal process = Q = + W
  • For a cyclic process = Q = - W

Chemistry-Thermodynamics-8651.png
  • r + s
  • r - s
  • s - r
  • rs

Chemistry-Thermodynamics-8653.png
  • - 26.4 kcal
  • 41.2 kcal
  • 26.4 kcal
  • 229.2 kcal
At 27° C one mole of an ideal gas is compressed isothermally and reversible from a pressure of 2 atm to 10 atm. The value of ∆ E and q are (R = 2 cal)
  • 0, - 965.84 cal
  • - 965.84 cal, - 865.58 cal
  • + 865.58 cal, - 865.58 cal
  • + 965.84 cal, + 865.58 cal
The internal energy changes when a system goes from state A to B is 40 kJ / mol. If the system goes from A to B by a reversible path and returns to state A by an irreversible path, what would be the net change in internal energy ?
  • 40 kJ
  • > 40 kJ
  • < 40 kJ
  • Zero

Chemistry-Thermodynamics-8656.png
  • 110.5 kJ / mol
  • 676.1 kJ / mol
  • 282.8 kJ / mol
  • 300.0 kJ / mol
A gas expands isothermally against a constant external pressure of 1 atm from a volume of 10 dm3 to a volume of 20 dm3. It absorbs 800 J of thermal energy from its surroundings. The ∆U is
  • - 312 J
  • + 123 J
  • - 213 J
  • + 231 J
In a closed container, a liquid is stirred with a paddle to increase the temperature. Which of the following is true ?
  • ∆ E = W ≠ 0 , q = 0
  • ∆ E = W = q ≠ 0
  • ∆ E = 0 , W = q ≠ 0
  • W = 0 , ∆ E = q ≠ 0
Two moles of helium gas expanded isothermally and irreversible at 27°C form volume 1 dm3 to 1 m3 at constant pressure of 100 k Pa. Calculate the work done.
  • 99900 kJ
  • 99900 J
  • 35464.65 kJ
  • 34465.65 J
The sublimation energy of I2 (s) is 57.3 kJ / mol and the enthalpy of fusion is 15.5 kJ / mol. The enthalpy of vaporisation of I2 is
  • 41.8 kJ / mol
  • - 41.8 kJ / mol
  • 72.8 kJ / mol
  • -72.8 kJ / mol
When two moles of hydrogen expands isothermally against a constant pressure of 1 atm, at 25° C from 15 L to 50 L, the work done (in litre atm) will be
  • 17.5
  • 35
  • 51.5
  • 70
The heat of combustion of sucrose, C12 H22 O11 (s) at constant volume is 1348.9 kcal mol-1 at 25°C, then the heat of reaction at constant pressure when steam is produced
  • -1348.9 kcal
  • -1342.34 kcal
  • +1250kcal
  • None of the above
The standard molar heat of formation of ethane, CO2 and water (l) are respectively -21.1, - 94.1 and - 68.3 kcal. The standard molar heat of combustion of ethane will be
  • - 372 kcal
  • 162 kcal
  • - 240 kcal
  • 183.5 kcal
The ratio of heats liberated at 298 K from the combustion of one kg of coke and by burning water gas obtained from 1 kg of coke is (Assume coke to be 100% carbon). (Given : enthalpies of combustion of C, CO and H2 as 393.5 kJ, 285 kJ, 285 kJ respectively all at 298 K)
  • 0.96 : 1
  • 0.79 : 1
  • 0.69 : 1
  • 0.86 : 1
On complete combustion, 0.246 g of an organic compound gave 0.198 g of CO2 and 0.1014 g of H2O. The ratio of carbon and hydrogen atoms in the compound
  • 1 : 3
  • 1 : 2
  • 2 : 5
  • 2 : 7
The standard enthalpies of formation of CO2 (g), H2O(l) and glucose (s) at 25°C are - 400 kJ / mol, -300 kJ / mol and -1300 kJ / mol, respectively. The standard enthalpy of combustion per gram of glucose at 25°C is
  • + 2900 kJ
  • - 2900 kJ
  • -16.11kJ
  • + 16.11kJ
The enthalpy of combustion of C6H6 (l) is - 3250 kJ. When 0.39 g of benzene is burnt in excess of oxygen in an open vessel, the amount of heat liberated is
  • 16.25 J
  • 16.25 kJ
  • 32.5 J
  • 32.5 kJ
A coffee cup calorimeter initially contains 125 g of water at a temperature of 24.2°C. After adding 10.5 g of KBr, the temperature becomes 21.1°C. The heat of solution is
  • 40 J/g
  • 117 J/g
  • 167.7 J/g
  • 420.05 J/g

Chemistry-Thermodynamics-8662.png
  • - 228.8 kJ
  • - 343.53 kJ
  • + 228.8 kJ
  • + 343.52 kJ
Consider the reaction,
4NO2(g) + O2(g) → 2N2O5(g) , ΔrH = -111 KJ.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)
  • - 165 kJ
  • + 54 kJ
  • + 219 kJ
  • - 219 kJ
Molar heat capacity of aluminium is 25 JK-1 mol-1. The heat necessary to raise the temperature of 54 g of aluminium (Atomic mass 27 g mol-1) from 30°C to 50°C is
  • 1.5 kJ
  • 0.5 kJ
  • 1.0 kJ
  • 2.5 kJ
  • 2.0 kJ
The amount of the heat released when 20 mL 0. 5M NaOH is mixed with 100 mL 0.1 M HCl is x kJ. The heat of neutralisation is
  • - 100 x kJ / mol
  • - 50 x kJ / mol
  • + 100 x kJ / mol
  • + 50 x kJ / mol
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 in NH3 is
  • - 964 kJ mol-1
  • + 352 kJ mol-1
  • + 1056 kJ mol-1
  • - 1102 kJ mol-1
In which of the following reactions, the enthalpy is the least ?

  • Chemistry-Thermodynamics-8669.png
  • 2)
    Chemistry-Thermodynamics-8670.png

  • Chemistry-Thermodynamics-8671.png

  • Chemistry-Thermodynamics-8672.png
The heat of neutralisation is highest for the reaction between

  • Chemistry-Thermodynamics-8673.png
  • 2)
    Chemistry-Thermodynamics-8674.png

  • Chemistry-Thermodynamics-8675.png

  • Chemistry-Thermodynamics-8676.png
When 0.2 g of 1-butanol was burnt in a suitable apparatus, the heat evolved was sufficient to raise the temperature of 200 g water by 5°C. The enthalpy of combustion of 1-butanol in kcal mol-1 will be
  • + 37
  • + 370
  • - 370
  • - 740
  • - 14.8
For the reactions A → B; ∆H = + 24 kJ / mol and B → C ; ∆H = -18 kJ / mol, the decreasing order of enthalpy of A, B, C follows the order
  • A ,B ,C
  • B ,C , A
  • C, B, A
  • C, A ,B
The heat of combustion of solid benzoic acid at constant volume is -321.30 kJ at 27° C. The heat of combustion at constant pressure is
  • - 321.30 - 300 R
  • - 321.30 + 300 R
  • - 321.30 - 150 R
  • - 321.30 + 900 R
0:0:1


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