CHEM-XI CHAP-11 (THERMOCHEMISTRY) WORKSHEET-1

1. For the reaction

NaOH + HCl ----- NaCl + H2O the change in enthalpy is called as:
A. heat of reaction B. heat of formation C. heat of neutralization D. heat of combustion
2. Calorie is equivalent to
A. 0.4184 J B. 41.84 J C. 4.184 J D. 418.4 J
3. 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 C. Hess’s law D. Law of conservation of
B. Joule’s principle Energy
4. If an endothermic reaction is allowed to take place very rapidly in the air. The temperature of the surrounding air
A. remains constant B. increase C. decrease D. remain unchanged
5. Pressure – volume work is
A. P ∆V B. F x d C. H ∆V D. H + PV
6. Kinetic energy of molecules is due to
A. rotational energy B. vibrational energy C. translational energy D. all of these
7. The condition for standard enthalpy change is
A. 1 atm 30 C B. 1 atm 0 C C. 1 atm 25 C D. 760 atm 25 C
8. An endothermic reaction is one is which
A. enthalpy of reactants and products are same C. enthalpy of products is lesser than reactant
B. enthalpy of products is greater than reactant D. sheat is evolved from system
9. An exothermic reaction is one in which
A. enthalpy of reactants and products are same D. enthalpy of reactants is lesser than products
B. heat is absorbed by system E. none of them
C. enthalpy of products is greater than reactants
10. All of the following statements are false except
A. q = ∆H at constant T; q = ∆E at constant V C. q = ∆H at constant P; q = ∆E at constant V
B. q = ∆H at constant V; q = ∆E at constant P D. q = ∆H = ∆E at constant P or at constant V
11. Calculate the standards molar enthalpy of formation of CO2(g) in the reaction:
C(g) +O2(g) -------- CO2(g)
Given the following standard enthalpy changes:
2C(s) +O2(g) ----- 2CO(g) ΔHo = -221kJ
2CO(g) + O2(g)------- 2CO2(g) ΔHo = -566kJ
A. -393.5 kJ B. +393.5 kJ C. +787.0 kJ D. -787.0 kJ
12. CO(g) + NO2(g) ------- CO2(g) + NO(g) ΔHo = ?
The enthalpy of this reaction as calculated from the following date is
CO(g) + 1\2O2(g) ---- CO2(g)ΔHo = -283kJ / mol
1\2O2(g) + NO(g) ---- NO2(g) ΔHo = 180.6kJ / mol
A. -102.4 kJ B. -322.1 kJ C. -373.3 kJ D. -463.6 kJ
13. A chemist heated a balloon by supplying 600 J of heat. The balloon expands doing 200 J of work against the atmospheric
pressure. The change in internal energy of
A. -800 J B. -400 J C. J D. +400 J
14. Sublimation vaporization melting and photosynthesis all are examples of
A. chemical processes C. biochemical processes
B. physical processes D. endothermic processes
15. If volume of a system is kept constant and heat is supplied to the system then
A. internal energy of the system increases and no work is done on the surrounding
B. internal energy of the system increases and work is done on the surrounding
C. no change in internal energy occurs
D. no work is done on the surrounding
16. Melting of ice at room temperature is
A. spontaneous exothermic process C. non-spontaneous exothermic process
B. spontaneous endothermic process D. non-spontaneous endothermic process
17. Which elements typically have a standard enthalpy of formation equal to zero?
A. The most stable form is conventionally assigned a value C. Graphite (carbon).
of zero. D. N2, O2, Cl2, Na, Cu
B. Noble gases. E. All of them
18. What is the heat of formation of SO3 using Hess's Law in the provided example?
S+3/2 O2 ------SO3∆Hf=?
S(S) + O2----- SO2 ∆H1 = —296.8kj/mol
SO2 + 1/202----- SO3 ∆H2 = -99.2KJ/mol
A. 396Kj\mol B. -396kj\mol C. -196.6Kj\mol D. 196 kj\mole
19. What is the primary purpose of the Born-Haber cycle in chemistry?
A. To calculate the molar mass of elements
B. To determine the atomic radius of ionic solids
C. To correlate the lattice energy of ionic solids with various energies in their formation
D. To measure the electrical conductivity of ionic compounds
20. Which of the following represents the formation of one mole of CsF from its constituent elements at standard conditions?
A. Cs(s) +0.5 F2(g) → CsF(s) B. Cs(g) + 0.5F2(g) → CsF(s) C. Cs(s) + 2F(g) → CsF(s) D. Cs(g) + F2(g) → CsF(s)
21. Entropy is a measure of:
A. Temperature change C. Pressure variation
B. The degree of disorder or randomness in a system D. The number of moles in a system
22. If work is done on the system without heat transfer which equation is used to calculate the change in energy?
A. ∆E = q B. ∆E = W C. ∆E = E2 - E1 D. ∆E = q - W

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 CHEM-XI CHAP-11 (THERMOCHEMISTRY) WORKSHEET-1
23. What is the enthalpy of a system?
A. The total heat content of a system at constant pressure.
B. The total heat content of a system at constant volume.
C. The total heat content of a system at variable pressure and volume.
D. The total internal energy of a system.
24. How many kilojoules is equivalent to 3.5 atm dm 3 of work?
A. kJ B. 0.035 kJ C. 0.356 kJ D. 3.5 kJ
25. In reactions involving solids or liquids what can be said about the value of P∆V in the context of the first law of
thermodynamics?
A. P∆V is always significant. C. P∆V is equal to the internal energy chang
B. P∆V is almost zero because of minimal volume changes. D. P∆V is equal to the enthalpy change.
26. The energy corresponds to the given thermochemical process is labeled as Na+(g)+F-1(g)--------NaF(s):
A. Ionization energy C. Lattice energy
B. Enthalpy of combustion D. Enthalpy of atomization
27. Standard enthalpy of formation of all of the following elements at 25°C and 1 atm pressure are zero except:
A. C(diamond) B. C(graphite) C. O2 D. N2
28. Which statement is incorrect:
A. For constant pressure process ∆H = ∆E + PAV C. For exothermic reactions ∆H ˃ 0
B. For constant volume process ∆E = q D. For Hess law ∑∆H0(Cycle) = 0
29. For the reaction NaCl(s) -------Na + (aq) + Cl − (aq) the change in enthalpy is called:
A. Heat of reaction B. Heat of formation C. Heat of combustion D. Heat of solution
30. Which statement is not correct about ∆Ho?
A. Ho of the reaction depends on temperature C. Ho of catalyzed and uncatalyzed reaction is same
B. H of reaction can be > or < zero
o
D. Ho is always < 0
31. Which of the following processes is always endothermic?
A. Atomization B. Neutralization C. Combustion D. Solution
32. According to Born Haber cycle H of ionic compound is determined by the formula H.
A. HoL.E = Hof - Hx B. HoL.E = Hx + oHf C. HoL.E = Hx - Hf D. HoL.E = Hat - Hx
33. Hess’s law is used to calculate
A. Heat of combustion B. Heat of formation C. Lattice energy D. All of above
34. Which is contrary to 1st law of thermodynamics
A. Energy can never be produced
B. Energy can neither be formed nor destroyed
C. In an adiabatic process work done is independent of its path
D. continuous production of work without supply of an equivalent amount of energy
35. Born Haber cycle is application of
A. Law of mass action C. Hess’s law
B. Rate law D. Equilibrium law
36. Neutralization of strong acid with strong base is
A. Non-spontaneous reaction C. Spontaneous and endothermic
B. Spontaneous and exothermic reaction D. Non-spontaneous endothermic reaction
37. The value of H and E are approximately the same for the process in case of liquids and solids because
A. There is no change in temperature C. volume change is negligible
B. Head absorbed D. Heat is released
38. If more bonds are broken than the bonds formed the reaction will be:
A. Exothermic B. Endothermic C. Both D. None
39. From the following data:
C(graphite)  C(g) ∆H = 716.7 kJ/mole
C(diamond  C(g) ∆H = 714.8 kJ/mole
Calculate ∆H for the reaction C(graphtie)  C(diamond).
A. 714.8 kJ B. 1.9 kJ C. Zero D. 1.9 kJ
40. When an exothermic reaction is reversed:
A. It becomes another exothermic reaction C. It becomes an endothermic process
B. It attains equilibrium D. There is no change at all
41. A system absorb 30 kJ of heat and does 20 kJ of work. The net internal energy of the system:
A. Increase by 10 kJ C. Increase by 30 kJ
B. Decrease by 10 kJ D. Decrease by 30 kJ
42. For which of the following equations does the enthalpy change represent the lattice energy of sodium chloride?
A. Na(𝑠) + 1/2 𝐶𝑙2 (𝑔) → 𝑁aCl(𝑠) C. 𝑁𝑎(𝑔) + 𝐶𝑙(𝑔) → 𝑁𝑎𝐶𝑙(𝑠)
B. 𝑁𝑎 +(𝑎𝑞) + 𝐶𝑙 −(𝑎𝑞) → 𝑁𝑎𝐶𝑙(𝑎𝑞) D. 𝑁𝑎 +(𝑔) + 𝐶𝑙 −(𝑔) → 𝑁𝑎𝐶𝑙(𝑠)
43. In thermochemistry force displacement work is replaced by:
A. Pressure volume work C. Temperature volume work
B. Pressure temperature work D. None of these
44. The value of the enthalpy change for the process represented by the equation 𝑵a(𝒔) → 𝑵𝒂 +(𝒈) + 𝒆 − is equal to:
A. The first ionization energy of sodium
B. The enthalpy change of vaporization of sodium.
C. The sum of the first ionization energy and the electron affinity of sodium.
D. The sum of the enthalpy change of sublimation and the first ionization energy of sodium.
45. All of the following reactions are exothermic EXCEPT:
A. N2(g)+3H2(g)⎯⎯→ 2NH3(g) B. C(s) + O2(g ) ⎯⎯→ CO2(g ) C. N2(g )+ O2 (g) ⎯⎯→ NO2(g ) D. H2(g)+1/2O2(g)⎯⎯→H2O(g)
46. Hess's Law is primarily useful for determining the heat of formation of compounds when:
A. Direct experimental determination is not possible C. All reactants are in the gaseous phase
B. Chemical reactions are well-understood D. Enthalpy changes are constant for all reaction

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 CHEM-XI CHAP-11 (THERMOCHEMISTRY) WORKSHEET-1
47. When the bonds being broken are more than those being formed in a chemical reaction then ∆H will be __________.
A. Positive B. Negative C. Zero D. None of these
48. The factor E + PV is known as __________.
A. Heat content B. Change in Enthalpy C. Work done D. All of these
49. Internal energy is a state function and only dependent on
A. Amount of substance C. On initial and final state of the system
B. Shapes of reactant D. all of these
50. Which one is intensive property?
A. Density B. Mass C. Mole D. Volume
51. Which one is extensive property?
A. Surface tension B. Viscosity C. Refractive index D. Gibb’s free energy
52. Heat absorbed at constant pressure
A. q p = Δ H B. q p = E2+PV2 C. q p = E1+ PV1 D. q p = H2
53. If 600 cals of heat if added to a system which systm does work equivalent to of 800 cals by expending against surrounding
what is the value of ∆E for the system
A. 200 B. -200 C. 1400 D. -1400
54. A process in which no heat enters or leaves the system is called
A. isothermal B. isobaric C. adiabatic D. isochoric
55. 110j heat is added to a system whose internal energy is 40j and then the amount of external work done is
A. 150 J B. 70 J C. 110 J D. 40 J
56. Which of the following are intensive properties?
1) Volume 2) density 3) specific heat
A. 3 only B. 2 and 3 only C. 1 and 3 only D. 1, 2 and 3
57. If internal energy of a system increases than which of the following change may take place?
A. State of the system may change C. Chemical reaction may take place
B. Temperature of the system may rise D. All of the above
58. Which of the enthalpy change is always positive
A. Heat of solution B. Heat of combustion C. Heat of neutralization D. Heat of atomization
59. Hess’s law is used to calculate
A. Heat of combustion B. Heat of formation C. Lattice energy D. All of above
60. Which of the following is not state function?
A. Internal energy B. Work C. Gibb’s free energy D. Enthalpy
61. An isolated system is the one:
A. that can transfer matter only D. that can transfer neither matter nor energy to and from
B. that can transfer energy only surrounding
C. that can transfer matter and energy
62. Determine ΔH for the reaction.
2Na + H2O + 1/2 O2  2NaOH ΔH=?
Na + 1/4 O2  1/2 Na2O ΔH = 50 k.cal
Na2O + H2O  2NaOH ΔH = -56 k.cal
A. 44 B. 156 C. -44 D. -156
63. Calculate the heat of formation of N2O4 from the following data:
2NO2(g)  N2O4(g)ΔH = ?
1/2 N2(g) + O2(g)  NO2(g) ΔH = + 33.95Kj/mole
N2(g) + 2O2(g)  N2O4(g) ΔH = + 9.3Kj/mole
A. 58.6 B. -58.6 C. -77.2 D. +77.2
64. Which of the following elements would have a standard enthalpy of formation of zero at 25°C and 1 atm?
A. Diamond (carbon). B. Graphite (carbon). C. Ozone (O3). D. monoclinic sulphure.
65. Calculate ∆H for the reaction:
3Mg + N2  Mg3 N2∆H = ?
3Mg + 2NH3  Mg3 N2 + 3H2 ∆H = -286KJ
½N2 + 3/2H2 NH3∆H = - 371KJ
A. 1032 B. -1028 C. -1032 D. 1028
66. How is the standard enthalpy of formation of an element with multiple allotropic forms determined?
A. It is always set to a constant value irrespective of the form.
B. The least stable form is use
C. The most stable form is conventionally assigned a value of zero.
D. It is determined experimentally for each form.
67. What is the expression for calculating the heat of formation of SO3 using Hess's Law in the provided example?
S+3/2 O2 ------SO3∆Hf=?
S(S) + O2----- SO2 ∆H1 = —296.8kj/mol
SO2 + 1/202----- SO3 ∆H2 = -99.2KJ/mol
A. ∆Hf(SO3) = ∆H1 - ∆H2 C. ∆Hf(SO3) = ∆H1 × ∆H2
B. ∆Hf(SO3) = ∆H1 + ∆H2 D. ∆Hf(SO3) = ∆H1 / ∆H2
68. Who developed the Born-Haber cycle to correlate the lattice energy of ionic solids with other energies involved in their
formation?
A. Max Born and Fritz Haber C. Marie Curie and Ernest Rutherford
B. Albert Einstein and Niels Bohr D. Linus Pauling and Richard Feynman
69. What is the primary purpose of the Born-Haber cycle in chemistry?
A. To calculate the molar mass of elements
B. To determine the atomic radius of ionic solids
C. To correlate the lattice energy of ionic solids with various energies in their formation
D. To measure the electrical conductivity of ionic compounds

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 CHEM-XI CHAP-11 (THERMOCHEMISTRY) WORKSHEET-1
70. Which of the following represents the formation of one mole of CsF from its constituent elements at standard conditions?
A. Cs(s) +1/2 F2(g) → CsF(s) C. Cs(s) + 2F(g) → CsF(s)
B. Cs(g) + 1/2F2(g) → CsF(s) D. Cs(g) + F2(g) → CsF(s)
71. Which step in the formation of CsF from its elements is an exothermic process?
A. Sublimation of Cesium C. Dissociation of Gaseous Fluorine
B. Ionization of Cesium D. Formation of CsF
72. What is the primary endothermic reaction responsible for the cooling effect in an instant cold pack?
A. The combustion of ammonium nitrate C. The evaporation of water
B. The dissolution of ammonium nitrate in water D. The decomposition of ammonium nitrate
73. How is the standard enthalpy of reaction (∆H°) calculated?
A. By measuring the temperature change during a reaction C. By adding the enthalpy of products to the enthalpy of
B. By subtracting the enthalpy of products from the reactants
enthalpy of reactants D. By finding the enthalpy of a single reactant
74. What is the Born-Haber Cycle used for in thermodynamics?
A. To determine the enthalpy of formation of a compound C. To estimate the enthalpy of sublimation of a substance
B. To calculate the enthalpy change during a phase D. To find the lattice energy of ionic compounds
transition
75. Entropy is a measure of:
A. Temperature change C. Pressure variation
B. The degree of disorder or randomness in a system D. The number of moles in a system
76. Which of the following is NOT a state function in thermodynamics?
A. Enthalpy B. Internal energy C. work done D. Heat transfer E. both c and d
77. What are the primary gases involved in gas welding?
A. Nitrogen and helium B. Acetylene and argon C. Oxygen and propane D. Acetylene and oxygen
78. In photosynthesis which of the following reactions is endothermic?
A. 2CO2 + 6H2O → C6H12O6 + 6O2 C. C + O2 → CO2
B. C6H12O6 + 6O2 → 2CO2 + 6H2O D. CH4 + 2O2 → 2CO2 + 2H2O
79. 5.Why is a negative sign added to the work equation in thermodynamics when dealing with gases at constant external
pressure?
A. To indicate the direction of gas flow C. To account for the fact that external pressure opposes
B. To make the equation more complex gas expansion
D. To simplify the equation
80. What is the relationship between atm.dm 3 and Joules for the unit of work?
A. 1 atm.dm3 = 100 Joules B. 1 atm.dm3 = 101.325 Joules C. 1 atm.dm3 = 10 Joules D. 1 atm.dm3 = 1000 Joules
81. Least entropy found in which of the following state of water:
A. Liquid water at 4°C B. Liquid water at 25°C C. Steam at 100°C D. Ice at 0°C
82. Standard enthalpy of formation of all of the following elements at 25°C and 1 atm pressure are zero except:
A. C(diamond) B. C(graphite) C. O2 D. N2
83. How many kilojoules is equivalent to 3.5 atm dm 3 of work?
A. kJ B. 0.035 kJ C. 0.356 kJ D. 3.5 kJ
84. Which one of the following is a state function?
A. Pressure B. Temperature C. Enthalpy D. All of the above
85. Change in enthalpy (H) of a system can be calculated by the following relationship
A. ΔH=ΔE+PΔV B. ΔH=ΔE-PV C. ΔH=ΔE-q D. ΔH=ΔE+q

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