JEE Chemistry Thermodynamics MCQs Set A

Question. Thermodynamics is not concerned about____.
(a) the rate at which a reaction proceeds
(b) the feasibility of a chemical reaction
(c) the extent to which a chemical reaction proceeds
(d) energy changes involved in a chemical reaction

Answer: A

Question. Which of the following statements is not true regarding the laws of thermodynamics ?
(a) It deal with energy changes of microscopic systems
(b) It deal with energy changes of macroscopic systems
(c) It does not depends on the rate at which these energy transformations are carried out
(d) It depends on initial and final states of a system undergoing the change.

Answer: A

Question. A ___________ in thermodynamics refers to that part of universe in which observations are made and remaining universe constitutes the……………...
(a) system, surroundings
(b) system, boundary
(c) surroundings, system

Answer: A

Question. The universe refers to
(a) both system and surroundings
(b) only surroundings
(c) only system
(d) None of these

Answer: A

Question. Which of the following statements is correct?
(a) The presence of reactants in a closed vessel made up of copper is an example of a closed system
(b) The presence of reactants in a thermos flask or any other closed insulated vessel is an example of a closed system.
(c) There is an exchange of energy as well as matter between the system and the surroundings in a closed system.
(d) The presence of reacting species in a covered beaker is an example of open system

Answer: A

Question. Which of the following is closed system ?
(a) Rocket engine during propulsion
(b) Pressure cooker
(c) Tea placed in a steel kettle
(d) Jet engine

Answer: A

Question. An isolated system is that system in which
(a) There is exchange of mass and energy with the surroundings
(b) There is no exchange of energy with the surroundings
(c) There is no exchange of mass or energy with the surroundings
(d) There is exchange of mass with the surroundings

Answer: A

Question. The state of a thermodynamic system is described by its measurable or macroscopic (bulk) properties. These are
(a) Pressure and temperature
(b) Volume, temperature and amount
(c) Pressure, volume, temperature and amount
(d) Pressure and volume

Answer: A

Question. Which of the following are not state functions ?
(I) q + w     (II) q
(III) w        (IV) H - TS
(a) (I), (II) and (III)
(b) (II) and (III)
(c) (II), (III) and (IV)
(d) (I) and (IV)

Answer: A

Question. Among the following the state function(s) is (are)
(i) Internal energy
(ii) Irreversible expansion work
(iii) Reversible expansion work
(iv) Molar enthalpy
(a) (i) and (iv)
(b) (ii) and (iii)
(c) (i), (ii) and (iii)
(d) (i) only

Answer: A

Question. ______ is a quantity which represents the total energy of the system
(a) Internal energy
(b) Electrical energy
(c) Chemical energy
(d) Mechanical energy

Answer: A

Question. Which of the following factors affect the internal energy of the system ?
(a) All of the above
(b) Matter enters or leaves the system.
(c) Work is done on or by the system
(d) Heat passes into or out of the system.

Answer: A

Question.  The system that would not allow exchange of heat between the system and surroundings through its boundary is considered as
(a) adiabatic
(b) isochoric
(c) isothermal
(d) isobaric

Answer: A

Question. The enthalpy change of a reaction does not depend on
(a) Different intermediate reactions
(b) Nature of reactants and products
(c) The state of reactants and products
(d) Initial and final enthalpy change of a reaction

Answer: A

Question. The q is ________  when heat is transferred from the surroundings to the system and q is………………………..
(a) positive , negative
(b) high, low
(c) negative , positive
(d) low, high

Answer: A

Question. Which of the following statements is incorrect?
(a) Both
(b) q is a path dependent function
(c) H is a state function
(d) None of these

Answer: A

Question. The work done during the expansion of a gas from a volume of 4 dm³ to 6 dm³ against a constant external pressure of 3 atm is (1 L atm = 101.32 J)
(a) – 608 J
(b) – 304 J
(c) – 6 J
(d) + 304 J

Answer: A

Question. An ideal gas expands in volume from 1×10^–3 to 1 × 10^–2 m³ at 300 K against a constant pressure of 1×105 Nm^–2. The work done is
(a) – 900 J
(b) 270 kJ
(c) – 900 kJ
(d) 900 kJ

Answer: A

Question. During isothermal expansion of an ideal gas, its
(a) enthalpy remains unaffected
(b) enthalpy reduces to zero
(c) enthalpy decreases
(d) internal energy increases

Answer: A

Question.  Among the following, the intensive properties are
(i) molar conductivity (ii) electromotive force
(iii) resistance            (iv) heat capacity
(a) (ii) and (iii)
(b) (i) and (iv)
(c) (i), (ii) and (iii)
(d) (i) only

Answer: A

Question. Which is an extensive property of the system ?
(a) Volume
(b) Temperature
(c) Viscosity
(d) Refractive index

Answer: A

Question. Which of the following is an example of extensive property?
(a) Mass
(b) Temperature
(c) Density
(d) Pressure

Answer: A

Question. Which of the following factors do not affect heat capacity?
(a) Temperature of the system
(b) Composition of system
(c) Size of system
(d) Nature of system

Answer: A

Question. The heat required to raise the temperature of body by 1 C° is called
(a) thermal capacity
(b) None of these
(c) specific heat
(d) water equivalent

Answer: A

Question. Equal volumes of two monoatomic gases, A and B, at same temperature and pressure are mixed. The ratio of specific heats (C_p/C_v) of the mixture will be
(a) 1.67
(b) 1.50
(c) 0.83
(d) 3.3

Answer: A

Question. The molar heat capacity of water at constant pressure is 75 JK^–1 mol^–1. When 1kJ of heat is supplied to 100 g of water, which is free to expand, the increase in temperature of water is
(a) 2.4 K
(b) 6.6 K
(c) 1.2 K
(d) 4.8 K

Answer: A

Question. Calorie is equivalent to
(a) 4.184 Joule
(b) 418.4 Joule
(c) 0.4184 Joule
(d) 41.84 Joule

Answer: A

Question. Which of the following is not true regarding thermo-chemical equations?
(a) The coefficients in a balanced thermo-chemical equation refer to the number of molecules of reactants and products involved in the reaction
(b) The coefficients in a balanced thermo-chemical equation refer to the number of moles of reactants and products involved in the reaction
(c) Both
(d) None of these

Answer: A

Question. The enthalpies of elements in their standard states are taken as zero. The enthalpy of formation of a compound
(a) may be positive or negative
(b) is always positive
(c) is always negative
(d) is never negative

Answer: A

Question. The enthalpy change for a reaction does not depend upon
(a) the nature of intermediate reaction steps
(b) use of different reactants for the same product
(c) the differences in initial or final temperatures of involved substances
(d) the physical states of reactants and products

Answer: A

Question. Bond dissociation enthalpy of H₂, Cl₂ and HCl are 434 , 242 and 431 kJ mol^–1 respectively. Enthalpy of formation of HCl is:
(a) – 93 kJmol^–1
(b) 93 kJ mol^–1
(c) – 245 kJmol^–1
(d) 245 kJmol^–1

Answer: A

Question. Hess’s law is used to calculate
(a) enthalpy of reaction
(b) work done in reaction
(c) entropy of reaction
(d) All of the above

Answer: A

Question. The enthalpy change on breaking one mole of bonds completely to obtain atoms in the gas phase is known as
(a) enthalpy of atomization.
(b) enthalpy of formation
(c) enthalpy of sublimation
(d) enthalpy of vaporization

Answer: A

Question. The heat of combustion of a substance is
(a) Always negative
(b) Numerically equal to the heat of formation
(c) Unpredictable
(d) Always positive

Answer: A

Question. Given that heat of neutralisation of strong acid and strong base is – 57.1 kJ. The heat produced when 0.25 mole of HCl is neutralised with 0.25 mole of NaOH in aqueous solution is :
(a) 14.275 kJ
(b) 22.5 kJ
(c) 57.1 kJ
(d) 28.6 kJ

Answer: A

Question. Pick out the wrong statement
(a) A process that leads to increase in free energy will be spontaneous
(b) The entropy of a perfectly crystalline substance at absolute zero is zero
(c) A process accompanied by decrease in entropy is spontaneous under certain conditions
(d) The standard free energy of formation of all elements is zero

Answer: A

Question. Identify the correct statement regarding a spontaneous process:
(a) For a spontaneous process in an isolated system, the change in entropy is positive.
(b) Lowering of energy in the process is the only criterion for spontaneity
(c) Endothermic processes are never spontaneous
(d) Exothermic processes are always spontaneous

Answer: A

Question. A chemical reaction will be spontaneous if it is accompanied by a decrease of
(a) free energy of the system
(b) internal energy of the system
(c) enthalpy of the system
(d) entropy of the system

Answer: A

Question. In which of the following entropy decreases?
(a) Crystallization of sucrose solution
(b) Rusting of iron
(c) Melting of ice
(d) Vaporization of camphor

Answer: A