JEE Questions for Chemistry Thermodynamics Quiz 8 - MCQExams.com

When a gas undergoes adiabatic expansion, it gets cooled due to
  • Loose of kinetic energy
  • Fall in temperature
  • Decrease in velocity
  • Energy used in doing work
For a reaction to occur spontaneously
  • (∆H – T∆S) must be negative
  • (∆S + T∆S) must be negative
  • ∆H must be negative
  • ∆S must be negative
A solution of 200 ml of 1 M KOH is a added to 200 ml of 1 M HCl and the mixture is well shaken. The rise in temperature T1 is noted. The experiment is repeated by using 100 ml of each solution and increase in temperature T2 is again noted. Which of the following is correct ?
  • T1 = T2
  • T2 is twice as large as T1
  • T1 is twice as large as T2
  • T1 is four times as large T2

Chemistry-Thermodynamics-8877.png

  • Chemistry-Thermodynamics-8878.png
  • 2)
    Chemistry-Thermodynamics-8879.png

  • Chemistry-Thermodynamics-8880.png

  • Chemistry-Thermodynamics-8881.png
Calculate the work done when 1 mole water at 373 K vaporizes against an atmosphereic pressure of 1.0 atomsphere. Assume ideal gas behaviour
  • - 6200 J
  • - 306 J
  • - 3100 J
  • - 1550 J
When one mole of an ideal gas is compressed to half of its initial volume and simultaneously heated to twice its initial temperature, the change in entropy (AS) is
  • Cv ln 2
  • Cp ln 2
  • R ln 2
  • (Cv - R) ln 2

Chemistry-Thermodynamics-8884.png
  • ‒ 131.2 kJ mol-1
  • 131.2 kJ mol-1
  • ‒ 262.4 kJ mol-1
  • 262.4 kJ mol-1
Which of the following relationships is correct?

  • Chemistry-Thermodynamics-8886.png
  • 2)
    Chemistry-Thermodynamics-8887.png

  • Chemistry-Thermodynamics-8888.png

  • Chemistry-Thermodynamics-8889.png
If a refrigerator’s door is opened, then we get
  • Room heated
  • Room cooled
  • More amount of heat is passed out
  • No effect on room
Warming ammonium chloride with sodium hydroxide in a test tube is an example of :
  • Closed system
  • Isolated system
  • Open system
  • None of these
A thermodynamic state function is
  • one which obeys all the laws of thermodynamics
  • a quantity which is used in measuring thermal changes
  • one which is used in thermo chemistry
  • a quantity whose value depends only on the state of the system.
In thermodynamics, a process is called reversible when
  • surroundings and system change into each other
  • there is no boundary between system and surroundings
  • the surroundings are always in equilibrium with the system
  • the system changes into the surroundings spontaneously
Which one of the following statement is false–
  • work is a state function
  • temperature is a state function
  • change in the state is completely defined when the initial and final states are specified
  • work appears at the boundary of the system
A mixture of two moles of carbon monoxide and one mole of oxygen, in a closed vessel is ignited to convert the carbon monoxide to carbon dioxide. If ∆H is the enthalpy change and ∆E is the change in internal energy, then
  • ∆H < ∆E
  • ∆H > ∆E
  • ∆H = ∆E
  • The relationship depends on the capacity of the vessel
At constant T and P, which one of the following statements is correct for the reaction,
Chemistry-Thermodynamics-8891.png
  • ∆H is independent of the physical state of the reactants of that compound
  • ∆H < ∆E
  • ∆H > ∆E
  • ∆H = ∆E
If ∆H is the change in enthalpy and the change in internal energy accompanying a gaseous reaction
  • ∆H is always greater than ∆E
  • ∆H < ∆E only if the number of moles of the products is greater than the number of the reactants
  • ∆H is always less than ∆E
  • ∆H < ∆E only if the number of moles of the products is less than the number of moles of the reactants
Enthalpy is an ................ property
  • Extensive
  • Exclusive
  • intensive
  • inclusive
Select the correct set of statement/s :
I. Work done by the surrounding in case of infinite stage expansion is more than single stage expansion
II. Irreversible work is always greater than reversible work.
III. On an ideal gas in case of single stage expansion and compression system as well as surrounding are restored back to their original states
IV. If gas is in thermodynamic equilibrium is taken from state A to state B, by four successive single stage expansions. Then we can plot 4 points on the P - V indicator diagram
  • II
  • I, II, III, IV
  • II, IV
  • I, II, IV
If W1, W2, W3 and W3 are work in isothermal, adiabatic, isobaric and isochoric reversible process, the correct order (for expansion) will be
  • W1 > W2 > W3 > W4
  • W3 > W2 > W1 > W4
  • W3 > W2 > W4 > W1
  • W3 > W1 > W2 > W4
The work done in ergs for the reversible expansion of one mole of an ideal gas from a volume of 10 litres to 20 litres at is
  • 2.303 × 298 × 0.082 log 2
  • 298 × 107 × 8.31 × 2.303 log 2
  • 2.303 × 298 × 0.082 log 0.5
  • 8.31 × 107 × 298 – 2.303 log 0.5
When Fe(s) is dissolved in aqueous HCl in a closed vessel the work done is
  • positive
  • negative
  • Zero
  • cannot be defined
Hess law of heat summation includes
  • initial reactants only
  • initial reactants a final products
  • Finial products only
  • intermediates only
Ice - water mass ratio is material as 1 : 1 in a given system containing water in equilibrium with ice at constant pressure. If CP (ice) = CP(water) = 4.18 J mol–1 K–1 molar heat capacity of a such a system is
  • Zero
  • infinity
  • 4.182 JK–1 mol–1
  • 75.48 JK–1 mol–1
During winters, moisture condenses in the form of dew and can be seen on plant leaves and grass. The entropy of the system in such cases decreases as liquid posses lesser disorder as compared to gases. With reference to the second law, which statement is correct, for the above process ?
  • The randomness of the universe decreases
  • The randomness of the surroundings decreases
  • increases is randomness of surroundings equals the decrease in randomness of system
  • The increase in randomness of the surroundings is greater as compared to the decreases in randomness of the system
The enthalpy change for a given reaction at 298 K is – x J mol–1 (x being positive). If the reaction occurs spontaneously at 298 K, the entropy change at that temperature
  • cannot be positive
  • can be negative but numerically larger than x/298
  • can be negative but numerically smaller than x/298
  • cannot be negative
Spontaneous adsorption of a gas on a solid surface is exothermic process because
  • enthalpy of the system increases
  • entropy increases
  • entropy decreases
  • free energy change increases
Identify the correct statement regarding entropy :
  • At absolute zero, the entropy of a perfectly crystalline substance is +ve
  • At absolute zero, the entropy of a perfectly crystalline substance is zero
  • At 0°C the entropy of a perfectly crystalline substance is taken to be zero
  • At absolute zero of temperature the entropy of all crystalline substances is taken to be zero
Identify the correct statement regarding a spontaneous process :
  • Exothermic processes are always spontaneous
  • Lowering of energy in the reaction process is the only criterion for spontaneity
  • For a spontaneous process in an isolated system, the change in entropy is positive
  • Endothermic processes are never spotaneous
∆S will be highest for the reaction

  • Chemistry-Thermodynamics-8893.png
  • 2)
    Chemistry-Thermodynamics-8894.png

  • Chemistry-Thermodynamics-8895.png

  • Chemistry-Thermodynamics-8896.png
The spontaneous flow of heat is always
  • unidirectional from higher temperature to lower temperature
  • from high to low pressure
  • unidirectional from lower temperature to higher temperature
  • from low to high pressure.
Which of the following is zero during adiabatic expansion of the gas
  • ∆T
  • ∆S
  • ∆E
  • All the above
The occurrence of a reaction is impossible if
  • ∆H is +ve; ∆S is also +ve but ∆H < T∆S
  • ∆H is –ve; ∆S is also –ve but ∆H > T∆S
  • ∆H is –Ve; ∆S is + Ve
  • ∆H is +ve; ∆S is –ve
Identify the correct statement regarding entropy
  • At 0oC, the entropy of a perfectly crystalline substance is taken to be zero
  • At absolute zero of temperature, the entropy of a perfectly crystalline substance is +ve
  • At absolute zero of temperature, the entropy of all crystalline substances is taken to be zero
  • At absolute zero of temperature, the entropy of a perfectly crystalline substance is taken to be zero
A container has hydrogen and oxygen mixture in ratio of 4 : 1 by weight, then
  • Internal energy of the mixture decreases
  • Internal energy of the mixture increases
  • Entropy of the mixture increases
  • Entropy of the mixture decreases
The second law of thermodynamics says that in cyclic process.
  • Work cannot be converted into heat
  • Heat cannot be converted into work
  • work cannot be completely converted into heat
  • Heat cannot be completely converted into work
A heat engine absorbs heat Q1 at temperature T1 and heat Q2 at temperature T2. Work done by the engine is (Q1 + Q2). This data
  • Violates Ist law of thermodynamics
  • Violates Ist law of thermodynamics if Q1 is –ve
  • Violates Ist law of thermodynamics if Q2 is –ve
  • Does not violate Ist law of thermodynamics
The molar neutralization heat for and as compared to molar neutralization heat of NaOH and HCl
  • Less
  • More
  • Equal
  • Depends on pressure
If the enthalpy of B is greater than of A, the reaction A → B is
  • Endothermic
  • Exothermic
  • Instantaneous
  • Spontaneous
Which of the following fuels will have the highest calorific value (kJ/kg)
  • Charcoal
  • Kerosene
  • Wood
  • Dung
A block of ice at –10 °C is slowly heated and converted into steam at 100°C .Which of the following curves represents the phenomenon qualitatively ?

  • Chemistry-Thermodynamics-8897.png
  • 2)
    Chemistry-Thermodynamics-8898.png

  • Chemistry-Thermodynamics-8899.png

  • Chemistry-Thermodynamics-8900.png
On passing CO2 gas in water, its entropy
  • Remains constant
  • Decreases
  • Increases
  • May increase or decrease
When does the reaction occur spontaneously on the basis of the relation ∆G° = –RT/nK?
  • K = 0
  • K = 1
  • K > 1
  • K < 1
In thermodynamics, a process is called reversible when,
  • Surroundings and system change into each other
  • The surroundings are always in equilibrium with the system
  • The system changes into the surroundings spontaneously
  • There is no boundary between system and surroundings
Under certain conditions, the value of ∆G for a hypothetical reaction, X + Y → Z is greater than zero, then –
  • The reaction has tendency to proceed towards Z
  • The reaction has attained equilibrium
  • increase in temperature increases the yield of product Z
  • X and Y predominate in the final mixture
For which of the following processes will energy be absorbed –
  • Separating an electron from an electron
  • Separating proton from a proton
  • Separating a neutron from neutron
  • Separating an electron from neutral atom
For the combustion of 1 mole of liquid benzene at 25ºC, the heat of reaction at constant pressure is given by, C6H6(l) + 7 O2 (g) → 6CO6 (g) + 3H6O (l); ∆H = –780980 cal.
What would be the heat of reaction at constant volume?
  • –780090 cal
  • –780890 cal
  • –780000 cal
  • –780900 cal
Calculate heat of the following reaction at constant pressure,
F2O(g) + H2O(g) → O2 (g) + 2HF(g)
The heats of formation of F2O (g), H2O(g) and HF (g) are 5.5 kcal, –57.8kcal and 64.2 kcal respectively.
  • 76.1 Kcal
  • 11.9 Kcal
  • 71.6 Kcal
  • 91.1 Kcal
Calculate the heat of formation of benzene from the following data, assuming no resonance. Bond energies :
C – C = 83 kcal = 140 kcal C – H = 99 kcal
Heat of atomisation of C = 170 .9 kcal
Heat of atomisation of H = 52.1 kcal
  • 70 Kcal
  • 75 Kcal
  • –75 Kcal
  • –70 Kcal
Calculate ∆H at 358 K for the reaction
Fe2O3(s) + 3H2(g) → 2Fe (s) + 3H2O(l)
Given that, ∆H298= – 33.29 kJ mole–1 and Cp for Fe2O3 (s), Fe (s), H2O (l) and H2 (g) are
103.8, 25.1, 75.3 and 28.8 J/K mole.
  • –22.22 KJ/mole
  • –25. 123 KJ/mole
  • –28.136 KJ/mole
  • – 30.135 KJ/mole
Ka for CH3COOH at 25ºC is 1.754 × 10–5 . At 50ºC, Ka is 1.633 × 10–5 What will be value of ∆Sº for the ionisation of CH3COOH?
  • –94.44 J/mole K
  • –96.66 J/mole K
  • –96.44 J/mole K
  • –90.44 J/mole K
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