SlideShare a Scribd company logo
1 of 9
Download to read offline
www.science360.net suresh gdvm
THERMODYNAMICS CHEMISTRY
PP
Practice Questions
EXERCISE - I
(Single & One or More than One Correct Answers)
1. 1 g H2
gas as STP is expanded so that volume is doubled. Hence, work done is
a) 22.4 L atm b) 5.6 L atm c) 11.2 L atm d) 1.135 K Joule
2. If x and y are two intensive variables then :
a) xy is an intensive variable b) x/y is an intensive variable
c) (x+y) is an intensive variable d) dx/dy is an extensive property
3. In a process a system does 140 J of work on the surroundings and only 40 J of heat is added to the
system, hence change in internal energy is
a) 180 J b) –180 J c) -23.92 Cal d) –100 J
4 A substance mass 10 kg at height of 10m is allowed to fall. At place where kinetic energy is 200 J
potential energy is
a) 580 J b) 780 J c) 186.6 Cal d) 350 Cal
5 Number of phases present in the following thermodynamic systems are :
1)      4 3 2NH HS s NH g H S g 2)      3 2CaCO s CaO s CO g
3)    2 2 3N g 3H 2NH g 
a) 2, 3, 1 b) 3, 2, 1 c) 1, 2, 3 d) 3, 1, 2
6. Two mole of an ideal gas is heated at constant pressure e of one atmosphere from 27 C
to 127 C.
If Cv, m
= 20 + 10–2
T JK–1
mol–1
, then q and U for the process are respectively.
a) 6362.8 J, 4700 J b) 1522.2 Cal, 1124.4 Cal
c) 7062.8, 5400 J d) 3181.4 J, 2350 J
7. Which of the following is /are true in the case of an adiabatic process
a) q = W b)  U q c) q = 0 d)  U W .
8. In the isothermal expansion of an ideal gas :
a)   0U b)   0T c)  0q d) W q .
9. During the isothermal expansion of an ideal gas :
a) the internal energy remains unaffected b) the temperature remains canstant
c) the enthalpy remains unaffected d) the enthalpy becomes zero.
10 Assuming that, water vapour is an ideal gas the internal energy change  U when 1 mol of water
is vaporised at 1 bar pressure and 1000
C (given : molar enthalpy of vaporisation of water at 1 bar
and 373K = 41 kJ mol–1
and R = 8.3 J K–1
mol–1
) will be
a) 41.00 kJ mol–1
b) 4.100 kJ mol–1
c) 3,7904 J mol–1
d) 37.904 kJ mol–1
CHEMISTRY THERMODYNAMICS
www.science360.net suresh gdvm
11. 1 mole of an ideal gas A(Cv,m
= 3R) and 2 mole of an ideal gas B are ,
3
2
 
  v mC R taken in a
container and expanded reversible and adiabatically from 1 lire to 4 litre starting from initial
temperature of 320 K. E or U for the process is
a) – 240 R b) 240 R
c) -1920 Cal mole–1
K–1
d) – 960 R
12. For polytropic process PVn
= constant, Cm
(molar heat capacity) of an ideal gas is given by
a)  v,m
R
C
n 1

 b)  v,m
R
C
1 n

 c) v,mC R d)  p,m
R
C
n 1


13. 2 mole of an ideal mono atomic gas undegoes a reversible process for which PV2 = C. The gas is
expanded from initial volume of 1 L to final volume of 3 L starting from initial temperature of
300 K. Find H for the process :
a) – 600 R b) – 1000 R
c) – 3000 R d) – 2 k Cal mole–1
K–1
14 For gaseous reaction, if H is the change in enthalpy and U that in internal energy then :
a) H is always greater than U b) H is always less than U
c) H < U only if the number of mole of the products is less than that of the reactants
d) U < H only if the number of mole of the reactants is less than that of the products
15. Which has / have a positive value(s) of H ?
a) H2(g)  2H(g)
b) H(g)  H+
(g)
+ e
c) H2
O(l)  H2
O(g)
d) H+
(aq)
+ OH–
(aq)  H2
O
16. The value of H U   for the following reaction at 270
C will be :      3 g 2 g 2 g2NH N 3H 
a) 8.314 x 273 x (–2) J b) 8.314 x 300 x (–2) J
c) -600 R d) 8.314 x 300 x 2 J
17. Which of the following reactions have same heat of reaction at constant temperature and at constant
volume?
a) H2(g)
+ Cl2(g)
 2HCl(g)
b) 2NO(g)
 N2(g)
+ O2(g)
c) CO3
O4(s)
+ 4CO(g)
 3CO(s)
+ 4CO2(g)
d)      2 2 3N g 3H g 2NH g 
18 When 1.0 g of oxalic acid (H2
C2
O4
) is burned in a bomb calorimeter whose heat capacity is 8.75 kJ/
K, the temperature increases by 0.312 K. The enthalpy of combustion of oxalic acid at 27 C
a) –245.7 kJ/mol b) –244.452 kJ/mol c) –246.947 kJ/mol d) -58.85 k Cal mol-1
19. The molar heat capacities at constant pressure (assumed constant with respect to temperature) at A,
B and C are in ratio of 3 : 1.5 : 2.0. The enthalpy change for the exothermic reaction A + 2B  3C
at 300K and 310K is 300H and 310H respectively then :
a) 300 310H H   b) 300 310H H   c) 300 310H H  
d) If T2
>T1
then 310 300H H   and if T2
< T1
then 310 300H H  
THERMODYNAMICS CHEMISTRY
www.science360.net suresh gdvm
20. The bond dissociation energies for Cl2
, I2
, and ICl are 242.3, 151 and 211.3 kJ/mol respectively.
The enthalpy of sublimation of iodine is 62.8 kJ/mol. What is the standard enthalpy of formation of
ICl(g)
?
a) –211.3 kJ/mol b) 4019 Cal/mol c) 16.8 kJ/mol d) 33.5 kJ/mol
21. The amount of heat released, when 20 mL of 0.5 M NaOH is mixed with 100 mL of 0.1 M HCl, is
x kJ. The heat of neutralization is
a) 10 x k Cal mole–1
b) 100 x kJ mole–1
c) - 100 x kJ mole–1
d) -23.92 k Cal mole–1
22. Enthalpy of neutralization of 3 3H PO acid is –106.68 kJ/mol using NaOH. If enthaly of neutralization
of HCl by NaOH is –55.84 kJ/mol. Calculate ionizationH of H3
PO3
into its ions
a) 50.84 kJ/mol b) 5 kJ/mol c) 2.5 kJ/mol d) 5000 J/mol
23 Consider the following data :  f 2 4H N H , 50 kJ/ mol, 
l  f 3H NH ,g 46 kJ/ mol,  
B.E. (N–H) = 393 kJ/mol and B.E. (H–H) = 436 kJ/mol, also  vap 2 4H N H , 18 kJ / mol l
The N–N bond energy in N2
H4
is
a) 226 kJ/mol b) 154 kJ/mol c) 190 kJ/mol d) 45.45 k Cal/mole
24. What is the bond enthalpy of Xe–F bond ?
         4 2XeF g Xe g F g F g F g ; 
    rH 292 kcal/ mol 
Given that I.E of Xenon = 279 k Cal / mole, B.E of F2
= 38 k Cal / mol, E.A of F = 85 k Cal / mole.
a) 24 k Cal/mol b) 34 k Cal/mol c) 8.5 k Cal/mol d) 142.12 kJ/mole
25 Which has maximum entropy change of vaporisation ?
a) water (l) b) toluene (l) c) diethyl either (l) d) acetone (l)
26. What are the signs of the entropy change (+ or –) in the following :
I : A liquid crystallises into a solid
II : Temperature of a crystalline solid is raised from 0 K to 115 K
III : 2 NaHCO3
(s)         2 3 2 3 2 2Na CO s Na CO s CO g H O g   IV :    2H g 2H g
I II III IV I II III IV
a) – + + + b) – – – +
b) – – – + d) + – – –
27. When charcoal burns in air signs of H and S are : 2C(s)
+ O2(g)  2CO(g)
H S H S H S H S
a) – – b) – + c) + + d) + –
28. When a liquid evaporates, which is true about the signs of the enthalpy and entropy changes ?
H S H S H S H S
a) + + b) – – c) + – d) – +
CHEMISTRY THERMODYNAMICS
www.science360.net suresh gdvm
29. Considering entropy(s) at a thermo dynamic parameter, the criterion for the spontanity of any process
is
a) system surroundingsS S 0    b) system surroundingsS S 0   
c) systemS 0  only d) surroundingsS 0  only
30. Calculate S for 3 mole of a diatomic ideal gas which is heated and compressed from 298 K and 1
bar to 596 K and 4 bar.
a) –14.7 cal K–1
b) +14.7 cal K–1
c) –4.9 cal K–1
d) 6.3 cal K–1
31. One mole of an ideal monoatomic gas at 270
C is subjected to a reversible isoentropic compression
until final temperature reached to 3270
C If the initial pressure was 1.0 atm then find the value of In
P2
:
a) 1.75 atm b) 0.176 atm c) 1.0395 atm d) 2.0 atm
32. Two mole of an ideal gas is expanded irreversibly and isothermally at 370
C until its volume is
doubled and 3.41 kJ heat is absorbed from surroundings. totalS (system + surroundings) is
a) – 0.52 J/K b) 0.52 J/K c) 22.52 J/K d) 0
33. For a perfectly cyrstalline solid 3
p,mC aT bT,  where a and b are constant. If p,mC is 0.40 J/K mol
at 10K and 0.92 J/K mol at 20 K, then molary entropy at 20 K is :
a) 0.92 J/K mol b) 8.66 J/K mol c) 0.813 J/K mol d) None of these
34. If the inversion temperature of a gas is –800
C, then it will produce cooling under Joule-Thomson
effect at
a) 298 K b) 273 K c) 193 K d) 173 K
35 Which of the following does not have zero entropy even at absolute zero ? CO, CO2
, NaCl, NO
a) CO, CO2
b) CO, NO c) CO2
, NaCl d) NaCl
36. Combustion of sucrose is used by aerobic organisms for providing energy for the life susting
processes. If all the capturing from the reaction is done through electrical process (non P–V work)
then calculate maximum available energy which can be captured by combustion of 34.2gm of
sucrose
Given : 
  1
( ) 6000combustionH sucrose kJ mol
 180 /combustionS J K mol and body temperature is 300 K.
a) 600 kJ b) 594.6 k Cal c) 144.83 k Cal d) 605.4 kJ
37. If G H T S     and
 
P
d G
G H T
dT
  
     
 
then variation of emf of a cell E, with temperature
T is given by :
a)
H
nF

b)
G H
nFT
 
c)
S
nF

d)
S
nF


38. For A B, H   3.5 kcal mol–1
, S = 10 cal mol–1
K–1
. Reaction is spontaneous when temperature can
be
a) 400 K b) 270
C c) 770
C d) 350 K
THERMODYNAMICS CHEMISTRY
www.science360.net suresh gdvm
39. Sign of G for the melting of ice is negative at
a) 265 K b) 270 K c) 277 K d) 274 K
40. Driving force of a reaction is the
a) resultant of enthalpy and entropy change
b) resultant of enthalpy and internal energy change
c) resultant of entropy and internal energy change
d) term concerned with change in free energy
41. G 
for the reaction x y z  is –4.606 kcal. The value of equilibrium constant of the reaction at
2270C is
a) 100 b) 10 c) 2 d) 0.01
42. Which of the following is true for spontaneous process ?
a) G > 0 b) G < 0 c) G = 0 d) G = TS
43 Which of the following expressions is correct ?
a) G nFE    b) G nFE   
c) cellG 2.303RTnFE    d) cG nF log K  
44 In the conversion of lime stone to lime, CaCO3(s)  CaO(s)
+ CO2(g)
the values of Ho
and So
are
+179.1 kJ mol–1
and 160.2 JK–1
mol–1 respectively at 298 K and 1 bar. Assuming , Ho
and So
do
not change with temperature; temperature above which conversion of lime stone to lime will be
spontaneous is
a) 1118 K b) 1008 K c) 1200 K d) 845 K
45. For H2
O(l)
(1 bar, 373K)  H2
O(g)
(1 bar, 373K). The correct set of thermodynamic parameters is
a) G = 0, S = + ve b) G = 0, S = – ve
c) G = +ve, S = 0 d) G = –ve, S = +ve
46 For the hypothetical reaction A2(g)
+ B2(g)
 2AB(g)
rG 
and rS 
are 20 kJ/mol and –20 JK–1
mol–1
respectively at 200 K.
If r pC is 20 JK–1
mol–1
then r H 
at 400 K is
a) 20 kJ/mol b) 7.98 kJ/mol c) 28 kJ/mol d) None of these
47 Calculate rG 
for (NH4
Cl, s) at 310 K.
Given : 0
f H for 4 r p(NH Cl,s) 314.5KJ / mol; C 0   
   2 2
0 1 1 0 1 1
N g H gS 192JK mol ; S 130.5JK mol ;   
     2 4
0 1 1 0 1 1
Cl g NH Cl sS 233JK mol ; S 99.5JK mol   
 
All given data at 300 K.
a) –198.56 kJ/mol b) –426.7 kJ/mol c) –202.3 kJ/mol d) None of these
CHEMISTRY THERMODYNAMICS
www.science360.net suresh gdvm
EXERCISE - II
(Linked Comprehension type questions)
Passage - I
Chemical reactions are invariably associated with the transfer of energy either in the form of heat or
light. In the laboratory, heat changes in physical and chemical processes are measured with an instrument
called calorimeter. Heat change in the process is calculated as : q = ms  T; s = Specific heat = c  T
c = Heat capacity. Heat of reaction at constant ressure is measured using simple or water calorimeter.
qv =  U = Internal energy change. Heat of reaction at consant pressure is measured using simple or
water calorimeter. qp
=  H ; Qp
= qv + P  V and  H =  U +  nRT. The amount of energy
released during a chemical change depends on the physical state of reactants andproducts, the condition
of pressure, temperature and volume at which the reaction is carried out. The variation of heat of
reaction with temperature and pressure is given by Kirchhoff’s equation :
2 1
p
2 1
H H
C ;
T T
  
 

2 1
2 1
U U
C
T T
  
 

v
(At constant pressure) (At constant volume)
48. The enthalpy of fusion of ice is 6.02 kJ mol–1
. the heat capacity of water is 4.18 J g–1
C–1
. What is the
smallest number of ice cubes at 00
C each containing one mole of water, that are needed to cool 500g
of liquid water from 200
C to 00
C ?
a) 1 b) 7 c) 14 d) 125
49. The enthalpy change  H for the reaction.      2 2 3N g 3H g 2NH g  is –92.38 kJ at 298 K. The
internal energy change U at 298 K is
a) –92.38 kJ b) –87.42 kJ c) 97.34 kJ d) –89.9 kJ
50 The specific heat of I2
in vapour and solid state are 0.031 and 0.055 cal/g respectively. The heat of
sublimation of iodine at 2000
C is 6.096 kcal mol–1
. The heat of sublimation of iodine at 2500
C will be
a) 3.8 kcal mol–1
b) 4.8 kcal mol–1
c) 2.28 kcal mol–1
d) 5.8 kcal mol–1
Passage - II : Consider the following energy level diagram :
Energy
O
6 12 6 2C H O +6O (g)
2 26CO ( ) 6 ( )g H O l
x
y z
2 26C(s)+6H (g)+9O (g)
Answer the following question on the basis of the given diagram :
51. The heat of formation of glucose is
a) –x b) –y c) x – y d) –x + z
52 In the given diagram z refers are
a) 2fCO6 x H 
b) 6 12 6fC H OH 
c) 6 12 6combustion C H OH 
d)  6 2
combustion C fH O iH H   
THERMODYNAMICS CHEMISTRY
www.science360.net suresh gdvm
53 The quantity y is equal to
a)    2combustion C s combustion H gH H   b) x + z
c) x –z d) 2 2fCO H OH H  
PASSAGE -III
The bond dissociation energy depends upon the nature of the bond and nature of the molecule. If any
molecule morethan 1 bonds are present of similar nature then the bond energy reported is the average
bond energy.
54 Determine C-C and C-H bond enthalpy (in kJ/mol) Given : 0
f 2 6H (C H ,g) 85kJ / mol   ,
0
f 3 8H (C H ,g) 104kJ / mol   , 0
subH (C,s) 718kJ / mol,  B.E. (H-H) = 436 kJ/mol,
a) 414, 345 b) 345, 414 c) 287, 405.5 d) None of these
55 Consider the following data : 0
f 2 4H (N H ,l) 50kJ / mol  0
f 3H (NH ,g) 46kJ / mol  
B.E. (N-H) = 393 kJ/mol and B.E. (H-H) = 436 kJ/mol, vap 2 4H(N H ,l) 18kJ / mol, 
The N-N bond energy in N2
H4
is :
a) 226 kJ/mol b) 154 kJ/mol c) 190 kJ/mol d) None of these
56 If enthalpy of hydrogenation of C6
H6(l)
into C6
H12(l)
is -205 kJ and resonance energy of C6
H6(l)
is
–152 kJ/mol then enthalpy of hydrogenation of is
Assume  Hvap
of C6
H6(l)
, C6
H10(l)
C6
H12(l)
all are equal :
a) – 535.5 kJ/mol b) – 238 kJ/mol c) – 357 kJ/mol d) – 119 kJ/mol
PASSAGE - IV
The thermodynamic property that measures the extent of molecular disorder is called entropy. The
direction of a spontaneous process for which the energy is constant is always the one that increases
the molecular disorder. Entropy change of phase transformation can be calculated using Trouton’s
formula
H
S
T
 
  
 
. In the reversible adiabatic process, however, S will be zero. The rise in
termperature in isobaric and isochoric conditions is found to increase the randomness or entropy of
the system.
S = 2.303C log (T1
/T2
) C = Cp
or Cv
57 The entropy change in an adiabatic process is :
a) zero b) always positive
c) always negative d) sometimes positive and sometimes negative
58 If, water in an insulated vessel at –100
C, suddenly freezes, the entropy change of the system will be
a) +10 J K–1
mol–1
b) –10 J K–1
mol–1
c) zero d) equal to that of surroundings
59. The melting point of a solid is 300 K and its latent heat of fusion is 600 cal mol–1
. The entropy
change for the fusion of 1 mole of the solid (in cal K–1
) at the same temperature would be :
a) 200 b) 2 c) 0.2 d) 20
CHEMISTRY THERMODYNAMICS
www.science360.net suresh gdvm
PASSAGE -V
G is a thermodynamic property the decrease in which value is the measure of useful work done
At constant temperature and pressure :
Gsystem
< 0 (spontaneous), Gsystem
= 0(equilibrium) Gsystem
> 0 (non - spnotaneous)
Free energy is related to the equilibrium constant, as : G0
= 2.303RT log10
Kc
60 If both H and S are negative, the reaction will be spontaneous :
a) at high temperature b) at low temperature
c) at all temperature d) at absolute zero
61 A reaction has positive values of H and S From this you can deduce that the reaction :
a) must be spontaneous at any temperature b) cannot be spontaneous at any temperature
c) will be spontaneous only at low temperature d) will be spontaneous only at high temperature
62 For a reaction to be spontaneous at all tempeatures :
a) G - ve, H+ ve and S+ ve b) G+ ve, H - ve and S+ ve
c) G - ve, H- ve and S- ve d) G = ve, H- ve and S+ v
Passage - VI
Standard Gibb’s energy of reaction  1G 
at a certain temperature can be computed as
1 1 rG H T S       and the change in the value of rH 
and rS 
for a reaction with temperature
can be computed as follows :  2 1r T r T r P 2 1H H C T T       
2 1
2
r T r T r P
1
T
S S C In
T
 
      
 
  
r r rG H T. S       and by r eqG RT In K  
Consider the following reaction :      2 3Co g 2H g CH OH g 
Given :  f 3H CH OH,g 
= –201 kJ/mol;  f H CO,g 114 kJ/ mol  
 3S CH OH,g 240 J / K mol; 
  1 1
2S H ,g 29 JK mol 

 S CO,g 198 J mol K; 
 p,m 2C H 28.8 J / mol K 
 p,mC CO 29.4 J / mol K 
;  p,m 3C CH OH 44 J / mol K 
and ln
320
300
 
 
 
= 0.06, all data at 300 K
63. rS 
at 300 K for the reaction is :
a) 152 63. J/K mole b) 181.6 J/K mole c) - 16 J/K mole d) None of these
64. rS 
at 320 K is
a)155.18 J/mol-K b) 150.02 J/mol-k c) 172 J/mol-K d) None of these
THERMODYNAMICS CHEMISTRY
www.science360.net suresh gdvm
65. rH 
at 320 K is
a) –288.86 kJ/mol b) –289.1 kJ/mol c) –87.86 kJ/mol d) None of these
EXERCISE - III
(Match the following questions)
66 Column-I Column-II
A) C (s, graphite) + O2
(g)  CO2
(g) p) combustionH 
B) C (s, grahpite)  C(g) q) formationH 
C)      2 2
1
CO g O g CO g
2
  r) atomizationH 
D)      4CH g C g 4H g  s) sublimationH 
67 Column-I (Process) Column-II (Entropy Change)
A) Reversible isothermal compression of ideal gas p) systemS 0 
B) Isothermal free expansion (Pext
= 0) of an ideal gas q) systemS 0 
C) Reversible adiabatic expansion of an ideal gas r) systemS 0 
D) Reversible ideal gas expansion s) Information insufficient
68 Column-I Column-II
A) Reversible adiabatic compression p) systemS 0 
B) Reversible vaporization of liquid q) systemS 0 
C)    22N g N g r) surroundingS 0 
D)      3 2MgCO s MgO s CO g

  s) surroundingS 0 
69 Column-I Column-II
a)  system T,P
G 0  p) Process is in equilibrium
b) system surrounding 0S S    q) Process is non spontaneous
c) system surrounding 0S S    r) Process is spontaneous
d)  system T,P
G 0  s) System is unable to do useful work
70 Column-I [ Sign H and S] Column-II
A) – & – p) Spontaneous only at low temperature
B) – & + q) Spontaneous only at high temperature
C) + & + r) Spontaneous at all temperature
D) + & – s) Non-Spontaneous at all temperature

More Related Content

What's hot

Chem 101 week 12 ch 5
Chem 101 week 12 ch 5Chem 101 week 12 ch 5
Chem 101 week 12 ch 5
tdean1
 
12 Gas Laws
12 Gas Laws12 Gas Laws
12 Gas Laws
janetra
 
Phys2 ch4-kineticsgas
Phys2 ch4-kineticsgasPhys2 ch4-kineticsgas
Phys2 ch4-kineticsgas
Đại Trần
 
AP Chemistry Chapter 3 Outline
AP Chemistry Chapter 3 OutlineAP Chemistry Chapter 3 Outline
AP Chemistry Chapter 3 Outline
Jane Hamze
 

What's hot (20)

Ch5 Gases
Ch5 GasesCh5 Gases
Ch5 Gases
 
Pembahasan Soal2 termokimia
Pembahasan Soal2 termokimiaPembahasan Soal2 termokimia
Pembahasan Soal2 termokimia
 
Ch3 stoichiometry
Ch3 stoichiometryCh3 stoichiometry
Ch3 stoichiometry
 
Analytical chemistry ch01 chemical measurements
Analytical chemistry ch01 chemical measurementsAnalytical chemistry ch01 chemical measurements
Analytical chemistry ch01 chemical measurements
 
chemical equilibrium for iit jee
chemical equilibrium for iit jeechemical equilibrium for iit jee
chemical equilibrium for iit jee
 
Ch4 Reactions in Aqueous Solution
Ch4 Reactions in Aqueous SolutionCh4 Reactions in Aqueous Solution
Ch4 Reactions in Aqueous Solution
 
Chem 101 week 12 ch 5
Chem 101 week 12 ch 5Chem 101 week 12 ch 5
Chem 101 week 12 ch 5
 
Ch4 Reactions in Aqueous Solution (updated)
Ch4 Reactions in Aqueous Solution (updated)Ch4 Reactions in Aqueous Solution (updated)
Ch4 Reactions in Aqueous Solution (updated)
 
Kinetic THEORY OF GASES
Kinetic THEORY OF GASES Kinetic THEORY OF GASES
Kinetic THEORY OF GASES
 
Solution Manual for Physical Chemistry – Robert Alberty
Solution Manual for Physical Chemistry – Robert AlbertySolution Manual for Physical Chemistry – Robert Alberty
Solution Manual for Physical Chemistry – Robert Alberty
 
Physical chemi gases
Physical chemi gasesPhysical chemi gases
Physical chemi gases
 
Basic concepts
Basic conceptsBasic concepts
Basic concepts
 
state of matter gases and liquids
state of matter  gases and liquidsstate of matter  gases and liquids
state of matter gases and liquids
 
Chapter 5 notes
Chapter 5 notesChapter 5 notes
Chapter 5 notes
 
Chapter 5
Chapter 5Chapter 5
Chapter 5
 
12 Gas Laws
12 Gas Laws12 Gas Laws
12 Gas Laws
 
Phys2 ch4-kineticsgas
Phys2 ch4-kineticsgasPhys2 ch4-kineticsgas
Phys2 ch4-kineticsgas
 
Class room work sheet (Crws) some basic concept of chemistry
Class room work sheet (Crws) some basic concept of chemistryClass room work sheet (Crws) some basic concept of chemistry
Class room work sheet (Crws) some basic concept of chemistry
 
AP Chemistry Chapter 3 Outline
AP Chemistry Chapter 3 OutlineAP Chemistry Chapter 3 Outline
AP Chemistry Chapter 3 Outline
 
Chapter 4 Thermochemistry
Chapter 4 ThermochemistryChapter 4 Thermochemistry
Chapter 4 Thermochemistry
 

Similar to Thermodynamics objective (11)

#22
#22#22
#22
 
Thermodynamics numericl 2016
Thermodynamics numericl 2016Thermodynamics numericl 2016
Thermodynamics numericl 2016
 
#22 Key
#22 Key#22 Key
#22 Key
 
Thermodynamic, sheet 2
Thermodynamic, sheet 2Thermodynamic, sheet 2
Thermodynamic, sheet 2
 
Chem 16 2 le answer key j4 feb 4 2011
Chem 16 2 le answer key j4 feb 4 2011Chem 16 2 le answer key j4 feb 4 2011
Chem 16 2 le answer key j4 feb 4 2011
 
Chem 16 2 le exam j4 feb 4 2011
Chem 16 2 le exam j4 feb 4 2011Chem 16 2 le exam j4 feb 4 2011
Chem 16 2 le exam j4 feb 4 2011
 
Thermodynamics mcqs.pptx
Thermodynamics mcqs.pptxThermodynamics mcqs.pptx
Thermodynamics mcqs.pptx
 
rep jee chem.docx
rep jee chem.docxrep jee chem.docx
rep jee chem.docx
 
Heat and THERMODYNAMICS
Heat and THERMODYNAMICSHeat and THERMODYNAMICS
Heat and THERMODYNAMICS
 
Chemical Reactions: Thermochemistry
Chemical Reactions: ThermochemistryChemical Reactions: Thermochemistry
Chemical Reactions: Thermochemistry
 
thermodynamics numericals TSH .pptx
thermodynamics numericals TSH       .pptxthermodynamics numericals TSH       .pptx
thermodynamics numericals TSH .pptx
 

More from suresh gdvm

More from suresh gdvm (20)

Chemical Thermodynamics
Chemical Thermodynamics Chemical Thermodynamics
Chemical Thermodynamics
 
Thermodynamics notes
Thermodynamics notesThermodynamics notes
Thermodynamics notes
 
Gaseous state
Gaseous stateGaseous state
Gaseous state
 
gaseous state - theory
gaseous state - theorygaseous state - theory
gaseous state - theory
 
Chemical bonding
Chemical bondingChemical bonding
Chemical bonding
 
Bonding
BondingBonding
Bonding
 
Chapter04
Chapter04Chapter04
Chapter04
 
Chembond
ChembondChembond
Chembond
 
Chap1
Chap1Chap1
Chap1
 
01 chemical bonding-theory-final-e
01 chemical bonding-theory-final-e01 chemical bonding-theory-final-e
01 chemical bonding-theory-final-e
 
01 chemical periodicity-theory-final-e
01 chemical periodicity-theory-final-e01 chemical periodicity-theory-final-e
01 chemical periodicity-theory-final-e
 
Periodic trends
Periodic trendsPeriodic trends
Periodic trends
 
09. classification2 (1)
09. classification2 (1)09. classification2 (1)
09. classification2 (1)
 
Atomic structure
Atomic structureAtomic structure
Atomic structure
 
Chapter01
Chapter01Chapter01
Chapter01
 
01 chemical arithmatic-theory
01 chemical arithmatic-theory01 chemical arithmatic-theory
01 chemical arithmatic-theory
 
Organic reaction mechanism full
Organic reaction mechanism fullOrganic reaction mechanism full
Organic reaction mechanism full
 
Nomenclature and introduction of major functional groups
Nomenclature and introduction of major functional groupsNomenclature and introduction of major functional groups
Nomenclature and introduction of major functional groups
 
Structure of atom Practice Exercise
Structure of atom Practice ExerciseStructure of atom Practice Exercise
Structure of atom Practice Exercise
 
Some basic concepts of chemistry
Some basic concepts of chemistrySome basic concepts of chemistry
Some basic concepts of chemistry
 

Recently uploaded

會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文
會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文
會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文
中 央社
 
Spellings Wk 4 and Wk 5 for Grade 4 at CAPS
Spellings Wk 4 and Wk 5 for Grade 4 at CAPSSpellings Wk 4 and Wk 5 for Grade 4 at CAPS
Spellings Wk 4 and Wk 5 for Grade 4 at CAPS
AnaAcapella
 
Transparency, Recognition and the role of eSealing - Ildiko Mazar and Koen No...
Transparency, Recognition and the role of eSealing - Ildiko Mazar and Koen No...Transparency, Recognition and the role of eSealing - Ildiko Mazar and Koen No...
Transparency, Recognition and the role of eSealing - Ildiko Mazar and Koen No...
EADTU
 

Recently uploaded (20)

e-Sealing at EADTU by Kamakshi Rajagopal
e-Sealing at EADTU by Kamakshi Rajagopale-Sealing at EADTU by Kamakshi Rajagopal
e-Sealing at EADTU by Kamakshi Rajagopal
 
Supporting Newcomer Multilingual Learners
Supporting Newcomer  Multilingual LearnersSupporting Newcomer  Multilingual Learners
Supporting Newcomer Multilingual Learners
 
Graduate Outcomes Presentation Slides - English (v3).pptx
Graduate Outcomes Presentation Slides - English (v3).pptxGraduate Outcomes Presentation Slides - English (v3).pptx
Graduate Outcomes Presentation Slides - English (v3).pptx
 
OS-operating systems- ch05 (CPU Scheduling) ...
OS-operating systems- ch05 (CPU Scheduling) ...OS-operating systems- ch05 (CPU Scheduling) ...
OS-operating systems- ch05 (CPU Scheduling) ...
 
OSCM Unit 2_Operations Processes & Systems
OSCM Unit 2_Operations Processes & SystemsOSCM Unit 2_Operations Processes & Systems
OSCM Unit 2_Operations Processes & Systems
 
Analyzing and resolving a communication crisis in Dhaka textiles LTD.pptx
Analyzing and resolving a communication crisis in Dhaka textiles LTD.pptxAnalyzing and resolving a communication crisis in Dhaka textiles LTD.pptx
Analyzing and resolving a communication crisis in Dhaka textiles LTD.pptx
 
DEMONSTRATION LESSON IN ENGLISH 4 MATATAG CURRICULUM
DEMONSTRATION LESSON IN ENGLISH 4 MATATAG CURRICULUMDEMONSTRATION LESSON IN ENGLISH 4 MATATAG CURRICULUM
DEMONSTRATION LESSON IN ENGLISH 4 MATATAG CURRICULUM
 
8 Tips for Effective Working Capital Management
8 Tips for Effective Working Capital Management8 Tips for Effective Working Capital Management
8 Tips for Effective Working Capital Management
 
An overview of the various scriptures in Hinduism
An overview of the various scriptures in HinduismAn overview of the various scriptures in Hinduism
An overview of the various scriptures in Hinduism
 
Including Mental Health Support in Project Delivery, 14 May.pdf
Including Mental Health Support in Project Delivery, 14 May.pdfIncluding Mental Health Support in Project Delivery, 14 May.pdf
Including Mental Health Support in Project Delivery, 14 May.pdf
 
Improved Approval Flow in Odoo 17 Studio App
Improved Approval Flow in Odoo 17 Studio AppImproved Approval Flow in Odoo 17 Studio App
Improved Approval Flow in Odoo 17 Studio App
 
AIM of Education-Teachers Training-2024.ppt
AIM of Education-Teachers Training-2024.pptAIM of Education-Teachers Training-2024.ppt
AIM of Education-Teachers Training-2024.ppt
 
Observing-Correct-Grammar-in-Making-Definitions.pptx
Observing-Correct-Grammar-in-Making-Definitions.pptxObserving-Correct-Grammar-in-Making-Definitions.pptx
Observing-Correct-Grammar-in-Making-Definitions.pptx
 
ESSENTIAL of (CS/IT/IS) class 07 (Networks)
ESSENTIAL of (CS/IT/IS) class 07 (Networks)ESSENTIAL of (CS/IT/IS) class 07 (Networks)
ESSENTIAL of (CS/IT/IS) class 07 (Networks)
 
會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文
會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文
會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文會考英文
 
male presentation...pdf.................
male presentation...pdf.................male presentation...pdf.................
male presentation...pdf.................
 
Spellings Wk 4 and Wk 5 for Grade 4 at CAPS
Spellings Wk 4 and Wk 5 for Grade 4 at CAPSSpellings Wk 4 and Wk 5 for Grade 4 at CAPS
Spellings Wk 4 and Wk 5 for Grade 4 at CAPS
 
TỔNG HỢP HƠN 100 ĐỀ THI THỬ TỐT NGHIỆP THPT TOÁN 2024 - TỪ CÁC TRƯỜNG, TRƯỜNG...
TỔNG HỢP HƠN 100 ĐỀ THI THỬ TỐT NGHIỆP THPT TOÁN 2024 - TỪ CÁC TRƯỜNG, TRƯỜNG...TỔNG HỢP HƠN 100 ĐỀ THI THỬ TỐT NGHIỆP THPT TOÁN 2024 - TỪ CÁC TRƯỜNG, TRƯỜNG...
TỔNG HỢP HƠN 100 ĐỀ THI THỬ TỐT NGHIỆP THPT TOÁN 2024 - TỪ CÁC TRƯỜNG, TRƯỜNG...
 
Transparency, Recognition and the role of eSealing - Ildiko Mazar and Koen No...
Transparency, Recognition and the role of eSealing - Ildiko Mazar and Koen No...Transparency, Recognition and the role of eSealing - Ildiko Mazar and Koen No...
Transparency, Recognition and the role of eSealing - Ildiko Mazar and Koen No...
 
Sternal Fractures & Dislocations - EMGuidewire Radiology Reading Room
Sternal Fractures & Dislocations - EMGuidewire Radiology Reading RoomSternal Fractures & Dislocations - EMGuidewire Radiology Reading Room
Sternal Fractures & Dislocations - EMGuidewire Radiology Reading Room
 

Thermodynamics objective

  • 1. www.science360.net suresh gdvm THERMODYNAMICS CHEMISTRY PP Practice Questions EXERCISE - I (Single & One or More than One Correct Answers) 1. 1 g H2 gas as STP is expanded so that volume is doubled. Hence, work done is a) 22.4 L atm b) 5.6 L atm c) 11.2 L atm d) 1.135 K Joule 2. If x and y are two intensive variables then : a) xy is an intensive variable b) x/y is an intensive variable c) (x+y) is an intensive variable d) dx/dy is an extensive property 3. In a process a system does 140 J of work on the surroundings and only 40 J of heat is added to the system, hence change in internal energy is a) 180 J b) –180 J c) -23.92 Cal d) –100 J 4 A substance mass 10 kg at height of 10m is allowed to fall. At place where kinetic energy is 200 J potential energy is a) 580 J b) 780 J c) 186.6 Cal d) 350 Cal 5 Number of phases present in the following thermodynamic systems are : 1)      4 3 2NH HS s NH g H S g 2)      3 2CaCO s CaO s CO g 3)    2 2 3N g 3H 2NH g  a) 2, 3, 1 b) 3, 2, 1 c) 1, 2, 3 d) 3, 1, 2 6. Two mole of an ideal gas is heated at constant pressure e of one atmosphere from 27 C to 127 C. If Cv, m = 20 + 10–2 T JK–1 mol–1 , then q and U for the process are respectively. a) 6362.8 J, 4700 J b) 1522.2 Cal, 1124.4 Cal c) 7062.8, 5400 J d) 3181.4 J, 2350 J 7. Which of the following is /are true in the case of an adiabatic process a) q = W b)  U q c) q = 0 d)  U W . 8. In the isothermal expansion of an ideal gas : a)   0U b)   0T c)  0q d) W q . 9. During the isothermal expansion of an ideal gas : a) the internal energy remains unaffected b) the temperature remains canstant c) the enthalpy remains unaffected d) the enthalpy becomes zero. 10 Assuming that, water vapour is an ideal gas the internal energy change  U when 1 mol of water is vaporised at 1 bar pressure and 1000 C (given : molar enthalpy of vaporisation of water at 1 bar and 373K = 41 kJ mol–1 and R = 8.3 J K–1 mol–1 ) will be a) 41.00 kJ mol–1 b) 4.100 kJ mol–1 c) 3,7904 J mol–1 d) 37.904 kJ mol–1
  • 2. CHEMISTRY THERMODYNAMICS www.science360.net suresh gdvm 11. 1 mole of an ideal gas A(Cv,m = 3R) and 2 mole of an ideal gas B are , 3 2     v mC R taken in a container and expanded reversible and adiabatically from 1 lire to 4 litre starting from initial temperature of 320 K. E or U for the process is a) – 240 R b) 240 R c) -1920 Cal mole–1 K–1 d) – 960 R 12. For polytropic process PVn = constant, Cm (molar heat capacity) of an ideal gas is given by a)  v,m R C n 1   b)  v,m R C 1 n   c) v,mC R d)  p,m R C n 1   13. 2 mole of an ideal mono atomic gas undegoes a reversible process for which PV2 = C. The gas is expanded from initial volume of 1 L to final volume of 3 L starting from initial temperature of 300 K. Find H for the process : a) – 600 R b) – 1000 R c) – 3000 R d) – 2 k Cal mole–1 K–1 14 For gaseous reaction, if H is the change in enthalpy and U that in internal energy then : a) H is always greater than U b) H is always less than U c) H < U only if the number of mole of the products is less than that of the reactants d) U < H only if the number of mole of the reactants is less than that of the products 15. Which has / have a positive value(s) of H ? a) H2(g)  2H(g) b) H(g)  H+ (g) + e c) H2 O(l)  H2 O(g) d) H+ (aq) + OH– (aq)  H2 O 16. The value of H U   for the following reaction at 270 C will be :      3 g 2 g 2 g2NH N 3H  a) 8.314 x 273 x (–2) J b) 8.314 x 300 x (–2) J c) -600 R d) 8.314 x 300 x 2 J 17. Which of the following reactions have same heat of reaction at constant temperature and at constant volume? a) H2(g) + Cl2(g)  2HCl(g) b) 2NO(g)  N2(g) + O2(g) c) CO3 O4(s) + 4CO(g)  3CO(s) + 4CO2(g) d)      2 2 3N g 3H g 2NH g  18 When 1.0 g of oxalic acid (H2 C2 O4 ) is burned in a bomb calorimeter whose heat capacity is 8.75 kJ/ K, the temperature increases by 0.312 K. The enthalpy of combustion of oxalic acid at 27 C a) –245.7 kJ/mol b) –244.452 kJ/mol c) –246.947 kJ/mol d) -58.85 k Cal mol-1 19. The molar heat capacities at constant pressure (assumed constant with respect to temperature) at A, B and C are in ratio of 3 : 1.5 : 2.0. The enthalpy change for the exothermic reaction A + 2B  3C at 300K and 310K is 300H and 310H respectively then : a) 300 310H H   b) 300 310H H   c) 300 310H H   d) If T2 >T1 then 310 300H H   and if T2 < T1 then 310 300H H  
  • 3. THERMODYNAMICS CHEMISTRY www.science360.net suresh gdvm 20. The bond dissociation energies for Cl2 , I2 , and ICl are 242.3, 151 and 211.3 kJ/mol respectively. The enthalpy of sublimation of iodine is 62.8 kJ/mol. What is the standard enthalpy of formation of ICl(g) ? a) –211.3 kJ/mol b) 4019 Cal/mol c) 16.8 kJ/mol d) 33.5 kJ/mol 21. The amount of heat released, when 20 mL of 0.5 M NaOH is mixed with 100 mL of 0.1 M HCl, is x kJ. The heat of neutralization is a) 10 x k Cal mole–1 b) 100 x kJ mole–1 c) - 100 x kJ mole–1 d) -23.92 k Cal mole–1 22. Enthalpy of neutralization of 3 3H PO acid is –106.68 kJ/mol using NaOH. If enthaly of neutralization of HCl by NaOH is –55.84 kJ/mol. Calculate ionizationH of H3 PO3 into its ions a) 50.84 kJ/mol b) 5 kJ/mol c) 2.5 kJ/mol d) 5000 J/mol 23 Consider the following data :  f 2 4H N H , 50 kJ/ mol,  l  f 3H NH ,g 46 kJ/ mol,   B.E. (N–H) = 393 kJ/mol and B.E. (H–H) = 436 kJ/mol, also  vap 2 4H N H , 18 kJ / mol l The N–N bond energy in N2 H4 is a) 226 kJ/mol b) 154 kJ/mol c) 190 kJ/mol d) 45.45 k Cal/mole 24. What is the bond enthalpy of Xe–F bond ?          4 2XeF g Xe g F g F g F g ;      rH 292 kcal/ mol  Given that I.E of Xenon = 279 k Cal / mole, B.E of F2 = 38 k Cal / mol, E.A of F = 85 k Cal / mole. a) 24 k Cal/mol b) 34 k Cal/mol c) 8.5 k Cal/mol d) 142.12 kJ/mole 25 Which has maximum entropy change of vaporisation ? a) water (l) b) toluene (l) c) diethyl either (l) d) acetone (l) 26. What are the signs of the entropy change (+ or –) in the following : I : A liquid crystallises into a solid II : Temperature of a crystalline solid is raised from 0 K to 115 K III : 2 NaHCO3 (s)         2 3 2 3 2 2Na CO s Na CO s CO g H O g   IV :    2H g 2H g I II III IV I II III IV a) – + + + b) – – – + b) – – – + d) + – – – 27. When charcoal burns in air signs of H and S are : 2C(s) + O2(g)  2CO(g) H S H S H S H S a) – – b) – + c) + + d) + – 28. When a liquid evaporates, which is true about the signs of the enthalpy and entropy changes ? H S H S H S H S a) + + b) – – c) + – d) – +
  • 4. CHEMISTRY THERMODYNAMICS www.science360.net suresh gdvm 29. Considering entropy(s) at a thermo dynamic parameter, the criterion for the spontanity of any process is a) system surroundingsS S 0    b) system surroundingsS S 0    c) systemS 0  only d) surroundingsS 0  only 30. Calculate S for 3 mole of a diatomic ideal gas which is heated and compressed from 298 K and 1 bar to 596 K and 4 bar. a) –14.7 cal K–1 b) +14.7 cal K–1 c) –4.9 cal K–1 d) 6.3 cal K–1 31. One mole of an ideal monoatomic gas at 270 C is subjected to a reversible isoentropic compression until final temperature reached to 3270 C If the initial pressure was 1.0 atm then find the value of In P2 : a) 1.75 atm b) 0.176 atm c) 1.0395 atm d) 2.0 atm 32. Two mole of an ideal gas is expanded irreversibly and isothermally at 370 C until its volume is doubled and 3.41 kJ heat is absorbed from surroundings. totalS (system + surroundings) is a) – 0.52 J/K b) 0.52 J/K c) 22.52 J/K d) 0 33. For a perfectly cyrstalline solid 3 p,mC aT bT,  where a and b are constant. If p,mC is 0.40 J/K mol at 10K and 0.92 J/K mol at 20 K, then molary entropy at 20 K is : a) 0.92 J/K mol b) 8.66 J/K mol c) 0.813 J/K mol d) None of these 34. If the inversion temperature of a gas is –800 C, then it will produce cooling under Joule-Thomson effect at a) 298 K b) 273 K c) 193 K d) 173 K 35 Which of the following does not have zero entropy even at absolute zero ? CO, CO2 , NaCl, NO a) CO, CO2 b) CO, NO c) CO2 , NaCl d) NaCl 36. Combustion of sucrose is used by aerobic organisms for providing energy for the life susting processes. If all the capturing from the reaction is done through electrical process (non P–V work) then calculate maximum available energy which can be captured by combustion of 34.2gm of sucrose Given :    1 ( ) 6000combustionH sucrose kJ mol  180 /combustionS J K mol and body temperature is 300 K. a) 600 kJ b) 594.6 k Cal c) 144.83 k Cal d) 605.4 kJ 37. If G H T S     and   P d G G H T dT            then variation of emf of a cell E, with temperature T is given by : a) H nF  b) G H nFT   c) S nF  d) S nF   38. For A B, H   3.5 kcal mol–1 , S = 10 cal mol–1 K–1 . Reaction is spontaneous when temperature can be a) 400 K b) 270 C c) 770 C d) 350 K
  • 5. THERMODYNAMICS CHEMISTRY www.science360.net suresh gdvm 39. Sign of G for the melting of ice is negative at a) 265 K b) 270 K c) 277 K d) 274 K 40. Driving force of a reaction is the a) resultant of enthalpy and entropy change b) resultant of enthalpy and internal energy change c) resultant of entropy and internal energy change d) term concerned with change in free energy 41. G  for the reaction x y z  is –4.606 kcal. The value of equilibrium constant of the reaction at 2270C is a) 100 b) 10 c) 2 d) 0.01 42. Which of the following is true for spontaneous process ? a) G > 0 b) G < 0 c) G = 0 d) G = TS 43 Which of the following expressions is correct ? a) G nFE    b) G nFE    c) cellG 2.303RTnFE    d) cG nF log K   44 In the conversion of lime stone to lime, CaCO3(s)  CaO(s) + CO2(g) the values of Ho and So are +179.1 kJ mol–1 and 160.2 JK–1 mol–1 respectively at 298 K and 1 bar. Assuming , Ho and So do not change with temperature; temperature above which conversion of lime stone to lime will be spontaneous is a) 1118 K b) 1008 K c) 1200 K d) 845 K 45. For H2 O(l) (1 bar, 373K)  H2 O(g) (1 bar, 373K). The correct set of thermodynamic parameters is a) G = 0, S = + ve b) G = 0, S = – ve c) G = +ve, S = 0 d) G = –ve, S = +ve 46 For the hypothetical reaction A2(g) + B2(g)  2AB(g) rG  and rS  are 20 kJ/mol and –20 JK–1 mol–1 respectively at 200 K. If r pC is 20 JK–1 mol–1 then r H  at 400 K is a) 20 kJ/mol b) 7.98 kJ/mol c) 28 kJ/mol d) None of these 47 Calculate rG  for (NH4 Cl, s) at 310 K. Given : 0 f H for 4 r p(NH Cl,s) 314.5KJ / mol; C 0       2 2 0 1 1 0 1 1 N g H gS 192JK mol ; S 130.5JK mol ;         2 4 0 1 1 0 1 1 Cl g NH Cl sS 233JK mol ; S 99.5JK mol      All given data at 300 K. a) –198.56 kJ/mol b) –426.7 kJ/mol c) –202.3 kJ/mol d) None of these
  • 6. CHEMISTRY THERMODYNAMICS www.science360.net suresh gdvm EXERCISE - II (Linked Comprehension type questions) Passage - I Chemical reactions are invariably associated with the transfer of energy either in the form of heat or light. In the laboratory, heat changes in physical and chemical processes are measured with an instrument called calorimeter. Heat change in the process is calculated as : q = ms  T; s = Specific heat = c  T c = Heat capacity. Heat of reaction at constant ressure is measured using simple or water calorimeter. qv =  U = Internal energy change. Heat of reaction at consant pressure is measured using simple or water calorimeter. qp =  H ; Qp = qv + P  V and  H =  U +  nRT. The amount of energy released during a chemical change depends on the physical state of reactants andproducts, the condition of pressure, temperature and volume at which the reaction is carried out. The variation of heat of reaction with temperature and pressure is given by Kirchhoff’s equation : 2 1 p 2 1 H H C ; T T       2 1 2 1 U U C T T       v (At constant pressure) (At constant volume) 48. The enthalpy of fusion of ice is 6.02 kJ mol–1 . the heat capacity of water is 4.18 J g–1 C–1 . What is the smallest number of ice cubes at 00 C each containing one mole of water, that are needed to cool 500g of liquid water from 200 C to 00 C ? a) 1 b) 7 c) 14 d) 125 49. The enthalpy change  H for the reaction.      2 2 3N g 3H g 2NH g  is –92.38 kJ at 298 K. The internal energy change U at 298 K is a) –92.38 kJ b) –87.42 kJ c) 97.34 kJ d) –89.9 kJ 50 The specific heat of I2 in vapour and solid state are 0.031 and 0.055 cal/g respectively. The heat of sublimation of iodine at 2000 C is 6.096 kcal mol–1 . The heat of sublimation of iodine at 2500 C will be a) 3.8 kcal mol–1 b) 4.8 kcal mol–1 c) 2.28 kcal mol–1 d) 5.8 kcal mol–1 Passage - II : Consider the following energy level diagram : Energy O 6 12 6 2C H O +6O (g) 2 26CO ( ) 6 ( )g H O l x y z 2 26C(s)+6H (g)+9O (g) Answer the following question on the basis of the given diagram : 51. The heat of formation of glucose is a) –x b) –y c) x – y d) –x + z 52 In the given diagram z refers are a) 2fCO6 x H  b) 6 12 6fC H OH  c) 6 12 6combustion C H OH  d)  6 2 combustion C fH O iH H   
  • 7. THERMODYNAMICS CHEMISTRY www.science360.net suresh gdvm 53 The quantity y is equal to a)    2combustion C s combustion H gH H   b) x + z c) x –z d) 2 2fCO H OH H   PASSAGE -III The bond dissociation energy depends upon the nature of the bond and nature of the molecule. If any molecule morethan 1 bonds are present of similar nature then the bond energy reported is the average bond energy. 54 Determine C-C and C-H bond enthalpy (in kJ/mol) Given : 0 f 2 6H (C H ,g) 85kJ / mol   , 0 f 3 8H (C H ,g) 104kJ / mol   , 0 subH (C,s) 718kJ / mol,  B.E. (H-H) = 436 kJ/mol, a) 414, 345 b) 345, 414 c) 287, 405.5 d) None of these 55 Consider the following data : 0 f 2 4H (N H ,l) 50kJ / mol  0 f 3H (NH ,g) 46kJ / mol   B.E. (N-H) = 393 kJ/mol and B.E. (H-H) = 436 kJ/mol, vap 2 4H(N H ,l) 18kJ / mol,  The N-N bond energy in N2 H4 is : a) 226 kJ/mol b) 154 kJ/mol c) 190 kJ/mol d) None of these 56 If enthalpy of hydrogenation of C6 H6(l) into C6 H12(l) is -205 kJ and resonance energy of C6 H6(l) is –152 kJ/mol then enthalpy of hydrogenation of is Assume  Hvap of C6 H6(l) , C6 H10(l) C6 H12(l) all are equal : a) – 535.5 kJ/mol b) – 238 kJ/mol c) – 357 kJ/mol d) – 119 kJ/mol PASSAGE - IV The thermodynamic property that measures the extent of molecular disorder is called entropy. The direction of a spontaneous process for which the energy is constant is always the one that increases the molecular disorder. Entropy change of phase transformation can be calculated using Trouton’s formula H S T        . In the reversible adiabatic process, however, S will be zero. The rise in termperature in isobaric and isochoric conditions is found to increase the randomness or entropy of the system. S = 2.303C log (T1 /T2 ) C = Cp or Cv 57 The entropy change in an adiabatic process is : a) zero b) always positive c) always negative d) sometimes positive and sometimes negative 58 If, water in an insulated vessel at –100 C, suddenly freezes, the entropy change of the system will be a) +10 J K–1 mol–1 b) –10 J K–1 mol–1 c) zero d) equal to that of surroundings 59. The melting point of a solid is 300 K and its latent heat of fusion is 600 cal mol–1 . The entropy change for the fusion of 1 mole of the solid (in cal K–1 ) at the same temperature would be : a) 200 b) 2 c) 0.2 d) 20
  • 8. CHEMISTRY THERMODYNAMICS www.science360.net suresh gdvm PASSAGE -V G is a thermodynamic property the decrease in which value is the measure of useful work done At constant temperature and pressure : Gsystem < 0 (spontaneous), Gsystem = 0(equilibrium) Gsystem > 0 (non - spnotaneous) Free energy is related to the equilibrium constant, as : G0 = 2.303RT log10 Kc 60 If both H and S are negative, the reaction will be spontaneous : a) at high temperature b) at low temperature c) at all temperature d) at absolute zero 61 A reaction has positive values of H and S From this you can deduce that the reaction : a) must be spontaneous at any temperature b) cannot be spontaneous at any temperature c) will be spontaneous only at low temperature d) will be spontaneous only at high temperature 62 For a reaction to be spontaneous at all tempeatures : a) G - ve, H+ ve and S+ ve b) G+ ve, H - ve and S+ ve c) G - ve, H- ve and S- ve d) G = ve, H- ve and S+ v Passage - VI Standard Gibb’s energy of reaction  1G  at a certain temperature can be computed as 1 1 rG H T S       and the change in the value of rH  and rS  for a reaction with temperature can be computed as follows :  2 1r T r T r P 2 1H H C T T        2 1 2 r T r T r P 1 T S S C In T               r r rG H T. S       and by r eqG RT In K   Consider the following reaction :      2 3Co g 2H g CH OH g  Given :  f 3H CH OH,g  = –201 kJ/mol;  f H CO,g 114 kJ/ mol    3S CH OH,g 240 J / K mol;    1 1 2S H ,g 29 JK mol    S CO,g 198 J mol K;   p,m 2C H 28.8 J / mol K   p,mC CO 29.4 J / mol K  ;  p,m 3C CH OH 44 J / mol K  and ln 320 300       = 0.06, all data at 300 K 63. rS  at 300 K for the reaction is : a) 152 63. J/K mole b) 181.6 J/K mole c) - 16 J/K mole d) None of these 64. rS  at 320 K is a)155.18 J/mol-K b) 150.02 J/mol-k c) 172 J/mol-K d) None of these
  • 9. THERMODYNAMICS CHEMISTRY www.science360.net suresh gdvm 65. rH  at 320 K is a) –288.86 kJ/mol b) –289.1 kJ/mol c) –87.86 kJ/mol d) None of these EXERCISE - III (Match the following questions) 66 Column-I Column-II A) C (s, graphite) + O2 (g)  CO2 (g) p) combustionH  B) C (s, grahpite)  C(g) q) formationH  C)      2 2 1 CO g O g CO g 2   r) atomizationH  D)      4CH g C g 4H g  s) sublimationH  67 Column-I (Process) Column-II (Entropy Change) A) Reversible isothermal compression of ideal gas p) systemS 0  B) Isothermal free expansion (Pext = 0) of an ideal gas q) systemS 0  C) Reversible adiabatic expansion of an ideal gas r) systemS 0  D) Reversible ideal gas expansion s) Information insufficient 68 Column-I Column-II A) Reversible adiabatic compression p) systemS 0  B) Reversible vaporization of liquid q) systemS 0  C)    22N g N g r) surroundingS 0  D)      3 2MgCO s MgO s CO g    s) surroundingS 0  69 Column-I Column-II a)  system T,P G 0  p) Process is in equilibrium b) system surrounding 0S S    q) Process is non spontaneous c) system surrounding 0S S    r) Process is spontaneous d)  system T,P G 0  s) System is unable to do useful work 70 Column-I [ Sign H and S] Column-II A) – & – p) Spontaneous only at low temperature B) – & + q) Spontaneous only at high temperature C) + & + r) Spontaneous at all temperature D) + & – s) Non-Spontaneous at all temperature