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self evaluation test on THERMODYNAMICS (CHEMISTRY) with answers., Exercises of Chemistry

It contains objective and assertion- reason type questions with detailed solutions.

Typology: Exercises

2021/2022

Available from 05/24/2022

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452 Thermodynamics and Thermochemistry
1. The internal energy change when a system goes
from state A to B is 40 kJ/mole. 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
[CBSE PMT 2003]
(a) 40 kJ (b) > 0 kJ
(c) < 40 kJ (d) Zero
2. The correct relationship is [DPMT 2002]
(a)
VVPH
(b)
EnRTH
(c)
PnRTE
(d) None of these
3. For
)(
3sCaCO
)()( 2gCOsCaO
at
C
o
977
;
176H
kJ mol, then
E
is [BVP 2003]
(a) 180 kJ (b) 186.4 kJ
(c) 165.6 kJ (d) 160 kJ
4. Values of
and
S
for five different reactions
are given below.
Reaction
)( 1
molkJH
)( 11
molJKS
I
II
III
IV
V
+98.0
55.5
+28.3
40.5
+ 34.7
+14.8
84.6
17.0
+24.6
0.0
On the basis of these values predict which one of
these will be spontaneous at all tempeature
[Kerala PMT 2004; KCET 1988,90]
(a) Reaction I (b) Reaction II
(c) Reaction III (d) Reaction IV
(e) Reaction V
5. Molar heat capacity of water in equilibrium with
ice at constant pressure is [I IT JEE 1997]
(a) Zero (b) Infinity
)(
(c)
11
45.40 molKkJ
(d)
1
48.75
KJ
6. Internal energy does not include
[AIIMS 1999; CPMT 2000]
(a) Nuclear energy
(b) Rotational energy
(c) Vibrational energy
(d) Energy arising by gravitational pull
7. Two moles of an ideal gas expand spontaneously
into a vacuum. The work done is [AMU 2000]
(a) 2 Joule (b) 4 Joule
(c) Zero (d) Infinite
8. Heat exchanged in a chemical reaction at constant
temperature and constant pressure is called as
[BHU 1998; Pb. PET 2000; MP PET 2002]
(a) Internal energy (b) Enthalpy
(c) Entropy (d) Free energy
9. Which of the following statements is true[KCET 2002]
(a)
E
is always greater than
H
(b)
E
is always less than
H
(c)
E
may be lesser or greater or equal to
H
(d)
E
is always proportional to
H
10. Mass and energy are conserved is demonstrated
by
[MH CET 2002]
(a) First law of thermodynamics
(b) Law of conservation of energy
(c) Law of conservation of mass
(d) Modified form of Ist law of thermodynamics
11. The enthalpy of the reaction,
)()(
2
1
)( 222 gOHgOgH
is
1
H
and that of
)()(
2
1
)( 222 lOHgOgH
is
2
H
. Then [KCET 2004]
(a)
21 HH
(b)
0
21 HH
(c)
21 HH
(d)
21 HH
12. A reaction occurs spontaneously if
[MP PET 2002; CBSE PMT 2005]
(a)
HST
and both
H
and
S
are +ve
(b)
HST
and both
H
and
S
are +ve
(c)
HST
and both
H
and
S
are +ve
(d)
HST
and
H
is +ve and
S
is ve
13. Which expression is correct for the work done in
adiabatic reversible expansion of an ideal gas[AMU 2002]
pf3
pf4

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1. The internal energy change when a system goes

from state A to B is 40 kJ/mole. 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

[CBSE PMT 2003]

(a) 40 kJ (b) > 0 kJ

(c) < 40 kJ (d) Zero

2. The correct relationship is [DPMT 2002]

(a)  HPV  V (b) H  nRT  E

(c)  E  nRT  P (d) None of these

3. For () 3

CaCO s ⇌ ( ) ()

2

CaO sCO g at C

o

H  176 kJ mol , then  E is [BVP 2003]

(a) 180 kJ (b) 186.4 kJ

(c) 165.6 kJ (d) 160 kJ

4. Values of  H and  S for five different reactions

are given below.

Reaction ( )

 1

HkJmol ( )

 1  1

SJK mol

I

II

III

IV

V

On the basis of these values predict which one of

these will be spontaneous at all tempeature

[Kerala PMT 2004; KCET 1988,90]

(a) Reaction I (b) Reaction II

(c) Reaction III (d) Reaction IV

(e) Reaction V

5. Molar heat capacity of water in equilibrium with

ice at constant pressure is [IIT JEE 1997]

(a) Zero (b) Infinity()

(c)

1 1

  1. 45

 

kJK mol (d)

1

  1. 48

J K

6. Internal energy does not include

[AIIMS 1999; CPMT 2000]

(a) Nuclear energy

(b) Rotational energy

(c) Vibrational energy

(d) Energy arising by gravitational pull

7. Two moles of an ideal gas expand spontaneously

into a vacuum. The work done is [AMU 2000]

(a) 2 Joule (b) 4 Joule

(c) Zero (d) Infinite

8. Heat exchanged in a chemical reaction at constant

temperature and constant pressure is called as

[BHU 1998; Pb. PET 2000; MP PET 2002]

(a) Internal energy (b) Enthalpy

(c) Entropy (d) Free energy

9. Which of the following statements is true [KCET 2002]

(a)  E

is always greater than  H

(b)  E is always less than H

(c)  E

may be lesser or greater or equal to  H

(d)  E is always proportional to H

10. Mass and energy are conserved is demonstrated

by

[MH CET 2002]

(a) First law of thermodynamics

(b) Law of conservation of energy

(c) Law of conservation of mass

(d) Modified form of I

st

law of thermodynamics

11. The enthalpy of the reaction,

() ()

2

1

( )

2 2 2

H gO gHOg is

1

 H

and that of

() ()

2

1

( )

2 2 2

H gO gHOl is

2

H. Then [KCET 2004]

(a)

1 2

H  H (b) 0

1 2

 H  H 

(c)

1 2

H  H (d)

1 2

 H  H

12. A reaction occurs spontaneously if

[MP PET 2002; CBSE PMT 2005]

(a) TS  H and both  H and  S are +ve

(b) TS  H and both  H and  S are +ve

(c) TS  H and both  H and  S are +ve

(d) TS  H and  H is +ve and  S is – ve

13. Which expression is correct for the work done in

adiabatic reversible expansion of an ideal gas [AMU 2002]

(a)

1

2

ln

V

V

WnRT (b)

1

2

ln

T

T

W n

e

(c) WPV (d)

2

1

W PdV

14. If an endothermic reaction is non-spontaneous at

freezing point of water and becomes feasible at

its boiling point, then

[AIEEE 2002]

(a)

H

is

ve

,

 S

is + ve

(b)

 H

and

 S

both are + ve

(c)

H and

 S

both are – ve

(d)

H

is + ve ,

 S

is – ve

15. What is the entropy change (in

 1  1

JK mol

) when

one mole of ice is converted into water at

C

o

0

(The enthalpy change for the conversion of ice to

liquid water is 6.0 kJ

 1

mol

at

C

o

0

) [CBSE PMT 2003]

(a) 21.98 (b) 20.

(c) 2.013 (d) 2.

16. One mole of

NaCl ( s ) on melting absorbed

  1. 5 kJ

of heat and its entropy is increased by

1

  1. 8

JK

The melting point of

NaCl is [DPMT 2004]

(a) 1059 K (b) 30.5 K

(c) 28.8 K (d) 28800 K

17. The enthalpy change

(  H )

for the process

2 4

N H gNgHg

in

1

1724

KJ mol

. If the

bond energy of

N  H

bond in ammonia is

1

391

KJ mol

. What is the bond energy of

N  N

bond is

2 4

NH

[MP PMT 2004]

(a)

1

160

KJ mol (b)

1

391

KJ mol

(c)

1

1173

KJ mol (d)

1

320

KJ mol

18. Liquid ammonia is used in refrigeration because

of its

[DCE 2003]

(a) High dipole moment

(b) High heat of vaporisation

(c) High basicity

(d) All of these

19. A cylinder of gas supplied by Bharat Petroleum is

assumed to contain

14 kg

of butane. It a normal

family requires

20 , 000 kJ

of energy per day for

cooking, butane gas in the cylinder last for ….

Days [Kerala PMT 2004]

c

H of C H 2658 KJpermole

4 10

(a) 15 days (b) 20 days

(c) 50 days (d) 40 days

(e) 32 days

20. The heat of neutralization of HCl by NaOH under

certain condition is – 55.9 kJ and that of HCN by

NaOH

is – 12.1 kJ. the heat of ionization of HCN

is [MP PET 2001]

(a)

1

  1. 0

kJmol (b)

1

  1. 8

kJmol

(c)

1

  1. 0

kJ mol (d)

1

  1. 8

kJ mol

21. Equilibrium constant of a reaction is related to

[AIIMS 1991]

(a) Standard free energy change

o

G

(b) Free energy change G

(c) Temperature T

(d) None

22. The standard Gibbs free energy change

o

G is

related to equilibrium constant

p

K as [MP PET/PMT 1998]

(a)

o

p

K   RT ln G (b)

o

G

p

RT

e

K

(c)

RT

G

K

o

p

 (d)

RT

G

p

o

K e

23. The standard enthalpy or the decomposition of

2 5

NO to

2

NO is 58.04 kJ and standard entropy of

this reaction is 176. 7 J / K. The standard free

energy change for this reaction at C

o

25 is [DCE 2004]

(a) – 5.38 kJ (b) 5.38 kJ

(c) 5.38 kJ (d) – 538 kJ

24. For the equilibrium ()

2

HOl ⇌ ()

2

HOg at 1 atm and

298 K

[AIIMS 2004]

(a) Standard free energy change is equal to zero

o

G

 14000 gm

gives 14000  45. 8

 641200 KJ

Family need 20 , 000 KJ / day

So gas full fill the requirement for

  1. 06 days

20. (d) 21. (a) G 2. 303 log k.

o

 

22. (d)

G RT

p

o

K e

 /

23. (d) 24. (b) For reaction ()

2

HOl ⇌ ()

2

HOg

n  1 means positive

so when  n is positive then  G  0.

25. (c)  G  HTS

G  0 at equilibrium

 HTS or 30. 56  T  0. 066

T  463 K.