Entry Test Preparation 2015
Chemistry
Chapter # 6
THERMOCHEMISTRY
Direction
You are given following questions from the topic, with four
choices A through D. Select the choice that will answer the question best.
1. An
endothermic reaction is one in which
A. Heat is converted into electricity
B. Heat is absorbed
C. Heat is evolved
D. Heat is
converted into mechanical work
2. Hess’s law
deals with
A. Changes in heat of reaction
B. Rate of
reaction
C. Equilibrium constant
D. Influence of
pressure on volume of a gas.
3.
Hneutralisation is always
A. Positive B. Negative
C. Zero D. Positive or negative
4. For a system
in equilibrium, G = 0, under conditions
of constant
A. Temperature and pressure B. Temperature
and Volume
C. Pressure and volume D. Energy
and volume
5. The
enthalpies of combustion of carbon and carbon monoxide are -390 kJ mol-1 and
-278 kJ mol-1 respectively. The enthalpy of formation of carbon monoxide is
A. 668 kJ mol-1 B. 112
kJ mol-1
C. -112 kJ mol-1 D. -668
kJ mol-1
6. For a
reaction to occur spontaneously
A. H must be negative B. H must be positive
C. H must be zero D.
H must be unity
7. The bond
dissociation energies of H2, CL2 and HCl are 104, 58 and 103 kcal respectively.
The enthalpy of formation of HCl gas will be
A. -44 kcal B. -88 kcal
C. -22 kcal D. -11 kcal
8. The reaction
is spontaneous if the cell potential is
A. positive B. negative
C. zero D. infinite
9. The heat
absorbed at constant volume is equal to the system’s change in
A. Enthalpy B. Entropy
C. Entropy
temperature D. Internal energy
10. The heat of
neutralization is maximum when
A. Sodium hydroxide is neutralized by
acetic acid
B. Ammonium hydroxide is neutralized by
acetic acid
C. Ammonium hydroxide is neutralized by
hydrochloric acid
D. Sodium
hydroxide is neutralized by hydrochloric acid
11. Free energy
change for a reversible process is
A. > 0 B. < 0
C. Equal to zero D. Unpredictable
12. An adiabatic
expansion of an ideal gas always has
A. Decrease in temperature B. q
= 0
C. W = 0 D. H = 0
13. C
(diamond) (Graphite), H = -ve. This show that
A. Graphite is more stable than diamond
B. Graphite has more energy than diamond
C. Both are equally stable
D. Stability cannot to predicted
14. What would be
the heat released when an aqueous solution containing 0.5 mol of HNO3 is mixed with
0.3 mol of OH- (enthalpy of neutralization is -57.1 kJ)
A. 28.5 kJ B. 17.1 kJ
C. 45.7 kJ D. 1.7 kJ
15. Which of the
following is not correct?
A. Dessolution of NH4Cl in excess of water
is an endothermic process
B. Neutralisation is always exothermic
C. The absolute value of enthalpy (H) can
be determined experimentally
D. The heat of reaction at constant volume
is denoted by E
16. Thermochemistry
is the study of chemical reaction accompanying
A. heat change B. rate
change
C. mass change D. volume
change
17. When a bond
breaks
A. heat is evolved
B. heat is
absorbs
C. no change in heat contents take place
D. temperature increases
18. One calorie
is equal to
A. 5.184 J B. 3.184 J
C. 4.184 J D. 7.184 J
19. One
kilocalorie is equal to
A. 4.184
103 J B. 4.184
104 J
C. 4.184
102 J D. none of these
20. The energy
required to break one mole of bonds to form neutral atoms is called
A. bond length B. bond
strength
C. bond energy D. none
of these
21. Heat absorbed
or released during the chemical reaction of physical process at constant
pressure is equal to
A. B.
C. q D. w
22. The standard
enthalpy change in the formation of 1 mole of a compound from its elements in
their standard physical states is
A. enthalpy of formation B. enthalpy
of atomization
C. enthalpy of neutralization D. internal
energy change
23. For a given
process, the heat changes at constant pressure (qp) and at constant volume (qv)
are related to each other as
A. qp = qv B. qp < qv
C. qp > qv D. qp = qv/2
24. The net heat
change in a chemical reaction is same whether it is brought about in two or
more different ways in one or several steps. It is known as
A. Henry’s law B. Joule’s
principle
C. Hess’s law D. Law
of conservation of energy
25. A special
application of the Hess’s law to binary ionic compounds of M+X- type in
calculation of their lattice energies is
A. enthalpy of reaction B. Born-haber cycle
C. first law of thermodynamics D. enthalpy
of combustion
26. Kinetic
energy of He gas molecules is due to
A. transnational motion B. rotational
motion
C. vibrational motion D. all of these
27. Kinetic
energy of He gas molecule is due to
A. transnational motion B. rotational
motion
C. vibrational motion D. all of these
28. Statement
enthalpy of combustion of H2 is – 285.8 KJ mole-1 then which is the standard
enthalpy of formation of water
A. +285.8 KH mole-1 B. -285.8
KJ mole-1
C. zero D. -218 KJ mole-1
29. The
mathematical form of first law of thermodynamics is
A. B.
C. D.
30. By applying
hess’s law, we cane calculate
A. B.
C. D. K
31. = E when
A. V=0 B.
C. D.
32. If is zero, then pressure-volume work is
A. zero B. +ve
C. -ve D. both (b) and (c)
33. For an
exothermic reaction, the sign of enthalpy will be
A. zero B. +ve
C. -ve D. both (b) and (c)
34. For the
reaction NaOH + HCl NaCl + H2O the
change in enthalpy is called
A. heat of reaction B. heat
of formation
C. heat of neutralization D. heat
of combustion
35. Which one of
the following cannot be measured by Hess’s law?
A. heat of combustion B. enthalpy change
C. heat of dissociation D. internal energy
36. When HCl is
formed, heat is evolved as:H2 + Cl2
2HCl +44K.. cals. The intrinsic energy of HCl is:
A. -22 K.cals B. 44
K.cals
C. -44 K.cals D. 22
K.cals
37. Heat of
combustion of substance is always:
A. positive B. negative
C. more than one D. less
than one
38. The relation
between enthalpy, internal energy, pressure and volume of the system is:
A. E
= H + PV B. H = E + PV
C. E
= P + PV D. P = E + PV
39. Heat of
reaction at constant volume is equal to its thermodynamical quantity:
A. H B. E
C. q D. S
40. State
function depends upon:
A. path B. Energy
C. Initial and final state D. Work
41. Which of the
following reactions is endothermic?
A. C2H5OH + O2 → CO2 + H2O
B. NaOH + HCl → NaCl + H2O
C. CH4 + 2O2 → CO2 + 2H2O
D. none of these
42. The frist law
of thermodynamics based on:
A. an open system B. a
closed system
C. and isolated system D. all of these
43. If heat is
given off by a system then:
A. q = 0 B. q > 0
C. q < 0 D. none of the above
44. In which of
the following reaction enthalpy is exothermic:
A. HCl + NaOH B. C+O2
C. Both a and b D. None
of these
45. Which of the
following units represents the largest amount of energy:
A. Calroric B. Joule
C. Erg D. Electron volt
46. The standard
enthalpy of formation of pure element in its most stable form is:
A. zero B. negligible
C. more than 10 D. less
than 10
47. What is the
change in internal energy of a system that absorbs 455j of heat and does work
325j of work?
A. 13.0J B. 130J
C. 425J D. 780J
48. The reaction
will be exothermic and H will have a negative
sign when:
A. HR > HP B. HR
< HP
C HR= Hp D. HR = HP
49. Use the
following equations;
N2(g) + 2O2(g) → N2O4(g) Ho = +9.2KJ
N2(g) + 2O2(g) → 2NO2(g)
Ho = +33.2KJ
The enthalpy changes for the reaction is:
2NO2(g) → N2O4(g) Ho = ?
A. -24KJ B. +24KJ
C. 42.4KJ D. -42.4KJ
50. Which of the
following is state function?
A. q B. Mass
C. H D. None
ANSWERS
(theRmochemistry)
1
|
B
|
2
|
A
|
3
|
B
|
4
|
A
|
5
|
C
|
6
|
A
|
7
|
C
|
8
|
A
|
9
|
D
|
10
|
D
|
11
|
C
|
12
|
B
|
13
|
A
|
14
|
B
|
15
|
C
|
16
|
A
|
17
|
B
|
18
|
C
|
19
|
A
|
20
|
C
|
21
|
B
|
22
|
A
|
23
|
C
|
24
|
C
|
25
|
B
|
26
|
D
|
27
|
D
|
28
|
B
|
29
|
D
|
30
|
A
|
31
|
A
|
32
|
A
|
33
|
C
|
34
|
C
|
35
|
D
|
36
|
A
|
37
|
B
|
38
|
B
|
39
|
B
|
40
|
C
|
41
|
D
|
42
|
C
|
43
|
C
|
44
|
A
|
45
|
A
|
46
|
A
|
47
|
B
|
48
|
A
|
49
|
A
|
50
|
C
|
1 comments:
49=b option
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