March 07, 2012

Thermodynamics - II One Mark Questions

1. According to Trouton's rule, the value of change in entropy of vaporization is
a) 21 cal. deg-1 mole-1                                b) 12 cal. deg– 1 mol
c) 21 kcal. deg. mole-1                               d) 12 kcal. deg. mol–1.
2. All the naturally occurring processes proceed spontaneously in a direction which leads to
a) decrease of entropy                               b) increase in enthalpy
c) increase in free energy                          d) decrease of free energy.
3. Change in Gibbs free energy is given by
a) ΔG = ΔH + TΔS                                    b) ΔG = ΔH – TΔS
c) ΔG = ΔH x TΔS                                    d) ΔG = TΔS - ΔH /
a) ΔG = ΔH + TΔS                                    b) ΔG = ΔH – TΔS
c) ΔG = ΔH x TΔS                                    d) ΔG = ΔH/TΔS.
4. Entropy (S) and the entropy change (ΔS) of a process
a) are path functions                                 b) are state functions
c) are constants                                         d) have no values.
5. Entropy is a _____ function.
a) state                   b) path                         c) exact                        d) inexact.
6. For the reaction 2Cl(g)  Cl2(g), the signs of ΔH and ΔS are respectively
a) +,-                      b) +, +                                     c) -,-                             d) -,+.
7. Free energy (G) and the free energy change (ΔG) correspond to the
a) system only       b) surrounding only     c) system and surrounding      d) all of these.
8. H2O(l)  H2O(g). In this process the entropy,
a) remains constant b) decreases               c) increases                  d) becomes zero.
9. If ΔG for a reaction is negative, the change is
a) spontaneous                                          b) non-spontaneous
c) reversible                                               d) irreversible /
a) spontaneous                                          b) non-spontaneous
c) reversible                                               d) equilibrium
10. In an adiabatic process which of the following is correct?
a) q = w                 b) q = 0                        c) ΔE = q                     d) PΔV = 0
11. In which of the following processes / the process is always non-feasible?
a) ΔH>O, ΔS>O                                       b) ΔH<O, ΔS>O
c) ΔH>O, ΔS<O                                       d) ΔH <O, ΔS<O.
12. Standard free energies of formation of elements are taken as
a) positive              b) negative                  c) zero                                     d) all of these
13. The amount of heat exchanged with the surrounding at constant temperature and pressure is called
a) ΔE                     b) ΔH                          c) ΔS                           d) ΔG.
14. The amount of heat exchanged with the surroundings at constant pressure is called
a) ΔE                     b) ΔH                          c) ΔS                           d) ΔG.
15. The entropy change (ΔS(fusion)) involved in the process of H2O(s)  H2O(l) at 0°C and 1 atm pressure involving ΔH(fusion) = 6008 Jmol–1 is
a) 22.007 Jmol–1 K–1                                  b) 22.007 Jmol K–1
c) 220.07 Jmol–1 K–1                                  d) 2.2007 Jmol–1 K–1.
16. The entropy change involved in the process water (liq) to water (vapor, 373K) involving ΔHvap = 40850 J mol–1 at 373K / The change of entropy for the process H2O(liq) → H2O(vap) involving ΔHvap = 40850 J mol-1 at 373 K is
a ) 120 J mol–1 K–1                                     b) 9.1 x 10-3 J mol–1 K–1
c) 109.52 J mol–1 K–1                                 d) 9.1 x 10-4 J mol–1 K–1 /
       a) 22.007 Jmol–1 K–1                                 b) 7.307 J mol–1 K–1
       c) 109.52 J mol–1 K–1                                d) 0.2287 J K–1 /
       a) 10.952 J mol–1 K–1                                b) 109.52 J mol–1 K–1
c) 100.952 J mol–1 K–1                               d) 1095.2 J mol–1 K–1
17. The network obtained from a system is given by
a) w – PΔV           b) w + PΔV                 c) – w + PΔV              d) – w – PΔV.
18. The percentage efficiency of a heat engine that operates between 127°C and 27°C is
a) 20%                   b) 50%                         c) 100%                       d) 25%.
19. Thermodynamic condition for irreversible spontaneous process at constant T and P is
a) ΔG<0                b) ΔS<0                       c) ΔG>0                      d) ΔH > 0.
20. When a liquid boils, there is
a) an increase in entropy                           b) a decrease in entropy
c) an increase in heat of vaporization        d) an increase to free energy.
21. Which of the following does not result in an increase in the entropy?
a) Rusting of iron                                      b) Crystallisation of sucrose from solution
c) Vaporisation of camphor                      d) Conversion of ice to water.
22. Which one of the following is a state function?
a) q                        b) Δq                           c) w                             d) ΔS.
23. In SI unit 1 eu is
a) 41.84 EU            b) 4.184 EU                c) 418.4 EU                 d) 4184 EU
24. The entropy change for the following process possessing ΔH (transition) as 2090 J.mol–1 

1 mole Sn (α, 13oC) 1 mole Sn (β, 13oC) is
a) 22.007 J mol–1 K–1                                b) 7.307 J. mol–1 K–1
c) 0.314J mol–1 K–1                                   d) 109.52 J mol–1 K–1

THREE MARKS    FIVE MARKS

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