Thermochemistry and Thermodynamics Test 3

Total Questions:50 Total Time: 75 Min



Questions 1 of 50

Question:Heat produced in calories by the combustion of one gram of carbon is called

Answers Choices:

Heat of combustion of carbon

Heat of formation of carbon

Calorific value of carbon

Heat of production of carbon

Questions 2 of 50

Question:Conditions of standard state used in thermochemistry is

Answers Choices:

\({0^o}C\) and 1 atm

\({20^o}C\) and 1 atm

\({25^o}C\) and 1 atm

\(0\,K\) and 1 atm

Questions 3 of 50

Question:Which of the following is not a state function

Answers Choices:

\(\Delta S\)

\(\Delta G\)

\(\Delta H\)

\(\Delta Q\)

Questions 4 of 50

Question:Which of the following is true for an adiabatic process

Answers Choices:

\(\Delta H = 0\)

\(\Delta W = 0\)

\(\Delta Q = 0\)

\(\Delta V = 0\)

Questions 5 of 50

Question:Consider the reaction : \({N_2} + 3{H_2} \to 2N{H_3}\) carried out at constant temperature and pressure. If \(\Delta H\) and \(\Delta U\) are the enthalpy and internal energy changes for the reaction, which of the following expression is true

Answers Choices:

\(\Delta H = 0\)

\(\Delta H = \Delta U\)

\(\Delta H < \Delta U\)

\(\Delta H > \Delta U\)

Questions 6 of 50

Question:Which of the following is the correct equation

Answers Choices:

\(\Delta U = \Delta Q - W\)

\(\Delta W = \Delta U + \Delta Q\)

\(\Delta U = \Delta W + \Delta Q\)

None of these

Questions 7 of 50

Question:Work done during isothermal expansion of one mole of an ideal gas from 10 atm to 1 atm at 300 K is (Gas constant = 2)

Answers Choices:

938.8 cal.

1138.8 cal.

1381.8 cal.

1581.8 cal.

Questions 8 of 50

Question:Joule-Thomson expansion is

Answers Choices:




None of these

Questions 9 of 50

Question:If gas, at constant temperature and pressure expands then its

Answers Choices:

Entropy increases and then decreases

Internal energy increases

Internal energy remains the same

Internal energy decreases

Questions 10 of 50

Question:For the reaction \(PC{l_5}(g) \to PC{l_3}(g) + C{l_2}(g)\)

Answers Choices:

\(\Delta H = \Delta E\)

\(\Delta H > \Delta E\)

\(\Delta H < \Delta E\)

None of these

Questions 11 of 50

Question:Mixing of non-reacting gases is generally accompanied by

Answers Choices:

Decrease in entropy

Increase in entropy

Change in enthalpy

Change in free energy

Questions 12 of 50

Question:An irreversible process occuring isothermally in an isolated system leads to

Answers Choices:

Zero entropy

An increase in the total entropy of the system

A decrease in the total entropy of the system

None of these

Questions 13 of 50

Question:When enthalpy and entropy change for a chemical reaction are \( - 2.5\, \times {10^3}\,cal\) and \(7.4\,cal\) \({\deg ^{ - 1}}\) respectively. Predict the reaction at \(298\,K\) is

Answers Choices:





Questions 14 of 50

Question:The total entropy change for a system and its surroundings increases, if the process is

Answers Choices:





Questions 15 of 50

Question:If 0.75 mole of an ideal gas expands isothermally at \({27^o}C\) from 15 litres to 25 litres, the maximum work obtained is

Answers Choices:

8.40 J

9.34 J

10.86 J

10.43 J

Questions 16 of 50

Question:In which of the following conditions a chemical reaction can not occur

Answers Choices:

\(\Delta H\) and\(\Delta S\) increase and \(T\Delta S > \Delta H\)

\(\Delta H\) and \(\Delta S\) decrease and \(\Delta H > T\Delta S\)

\(\Delta H\) increases and \(\Delta S\) decreases

\(\Delta H\) decreases and \(\Delta S\) increases

Questions 17 of 50

Question:The unit of entropy is

Answers Choices:

\(J\,mo{l^{ - 1}}\)

\(JK\,mo{l^{ - 1}}\)

\(J\,mo{l^{ - 1}}{K^{ - 1}}\)

\({J^{ - 1}}{K^{ - 1}}mo{l^1}\)

Questions 18 of 50

Question:The entropy changed involved in the conversion of 1 mole of liquid water at 373 K to vapour at the same temperature will be \([\Delta {H_{{\rm{vap}}}} = 2.257kJ/gm]\)

Answers Choices:

0.119 kJ

0.109 kJ

0.129 kJ

0.120 kJ

Questions 19 of 50

Question:When a liquid boils, there is

Answers Choices:

An increase in entropy

A decrease in entropy

An increase in heat of vaporization

An increase in free energy

Questions 20 of 50

Question:A process is taking place at constant temperature and pressure. Then

Answers Choices:

\(\Delta H = \Delta E\)

\(\Delta H = T\Delta S\)

\(\Delta H = 0\)

\(\Delta S = 0\)

Questions 21 of 50

Question:The enthalpy of vapourization of a liquid is \(30\,kJ\,mo{l^{ - 1}}\) and entropy of vapourization is \(75\,J\,mo{l^{ - 1}}K\). The boiling point of the liquid at 1 atm is

Answers Choices:





Questions 22 of 50

Question:If \(C + {O_2} \to C{O_2} + 94.2\,kcal\) , \({H_2} + \frac{1}{2}{O_2} \to {H_2}O + 68.3\,kcal\), \(C{H_4} + 2{O_2} \to C{O_2} + 2{H_2}O + 210.8\,kcal\), then the possible heat of methane will be

Answers Choices:

47.3 kcal

20.0 kcal

45.9 kcal

47.3 kcal

Questions 23 of 50

Question:Which of the following statement is correct

Answers Choices:

\(\Delta H\) is positive for exothermic reaction

\(\Delta H\) is negative for endothermic reaction

The heat of neutralization of strong acid and strong base is always the same

The enthalpy of fusion is negative

Questions 24 of 50

Question:The absolute enthalphy of neutralisation of the reaction \(MgO(s) + 2HCl(aq) \to MgC{l_2}(aq) + {H_2}O(l)\)will be

Answers Choices:

Less than \( - 57.33\;kJ\;mo{l^{ - 1}}\)

\( - 57.33\;kJ\;mo{l^{ - 1}}\)

Greater than \( - 57.33\;kJ\;mo{l^{ - 1}}\)

\(57.33\;kJ\;mo{l^{ - 1}}\)

Questions 25 of 50

Question:\(\Delta H{^\circ _f}\) (298 K) of methanol is given by the chemical equation

Answers Choices:

\(C{H_4}(g) + 1/2{O_2}(g) \to C{H_3}OH(g)\)

C (graphite) \( + 1/2{O_2}(g) + 2{H_2}(g) \to C{H_3}OH(l)\)

C (diamond) \( + 1/2{O_2}(g) + 2{H_2}(g) \to C{H_3}OH(l)\)

\(CO(g) + 2{H_2}(g) \to C{H_3}OH(l)\)

Questions 26 of 50

Question:Heat of combustion \(\Delta H\) of \(C{H_4},\,{C_2}{H_6},\,{C_2}{H_4}\) and \({C_2}{H_2}\) gases are -212.8, -373.0, -337.0 and -310.5 kcal respectively at the same temperature. The best fuel among these gases is

Answers Choices:





Questions 27 of 50

Question:Heat of formation of \(C{O_2}(g),\,\,{H_2}O(l)\) and \(C{H_4}(g)\) are -94.0, -68.4 and -17.9 kcal respectively. The heat of combustion of methane is

Answers Choices:

212.9 kcal

136.8 kcal

304.3 kcal

105.2 kcal

Questions 28 of 50

Question:The heat of reaction does not depend upon

Answers Choices:

Temperature of the reaction

Physical state of reactants and products

Whether the reaction is carried out at constant pressure or at constant volume

The method by which the final products are obtained from the reactants

Questions 29 of 50

Question:A solution of \(500ml\) of \(0.2\,M\,KOH\) and \(500\,ml\) of \(0.2\,M\,HCl\) is mixed and stirred; the rise in temperature is \({T_1}\). The experiment is repeated using \(250\,ml\) each of solution, the temperature raised is \({T_2}\). Which of the following is true

Answers Choices:

\({T_1} = {T_2}\)

\({T_1} = 2{T_2}\)

\({T_1} = 4{T_2}\)

\({T_2} = 9{T_1}\)

Questions 30 of 50

Question:Enthalpy of a compound is equal to its

Answers Choices:

Heat of combustion

Heat of formation

Heat of reaction

Heat of solution

Questions 31 of 50

Question:\({H_2} + \frac{1}{2}{O_2} \to {H_2}O;\,\Delta H = - 68.39\,kcal\) , \(K + {H_2}O + \)Water \( \to KOH(aq) + \frac{1}{2}{H_2};\,\Delta H = - 48\,kcal\) , \(KOH + \)Water \( \to KOH(aq);\,\Delta H = - 14\,kcal\). The heat of formation of \(KOH\) is (in kcal)

Answers Choices:

\( - 68.39 + 48 - 14\)

\( - 68.39 - 48 + 14\)

\(68.39 - 48 + 14\)

68.39 + 48 + 14

Questions 32 of 50

Question:Which of the following reaction can be used to define the heat of formation of \(C{O_2}(g)\)

Answers Choices:

\(C{\rm{(graphite)}} + {O_2}(g) = C{O_2}(g)\)

\(C{H_4}(g) + 2{O_2}(g) = C{O_2}(g) + 2{H_2}O(l)\)

\(CO(g) + \frac{1}{2}{O_2}(g) = C{O_2}(g)\)

\({C_6}{H_6}(l) + 7\frac{1}{2}{O_2}(g) = 6C{O_2} + 3{H_2}O(l)\)

Questions 33 of 50

Question:For the allotropic change represented by equation \(C(diamond) \to C(graphite)\); the enthalpy change is \(\Delta H = - 1.89\,kJ\). If \(6\,g\) of diamond and \(6\,g\) of graphite are separately burnt to yield carbon dioxide, the heat liberated in the first case is

Answers Choices:

Less than in the second case by \(1.89\,kJ\)

More than in the second case by \(1.89\,kJ\)

Less than in the second case by \(11.34\,kJ\)

More than in the second case by \(0.945\,kJ\)

Questions 34 of 50

Question:For an exothermic reaction

Answers Choices:

\(H\) of the products is less than \(H\) of the reactants

\(H\) of the products is more than \(H\) of the reactants

\(H\) of the products is equal to \(H\) of the reactants

\(\Delta H\) is always positive

Questions 35 of 50

Question:\(C + \frac{1}{2}{O_2} \to CO;\,\Delta H = - 42\,kJ\), \(CO + \frac{1}{2}{O_2} \to C{O_2};\,\Delta H = - 24\,kJ\) . The heat of formation of \(C{O_2}\) is

Answers Choices:

16 kJ

+ 66 kJ

+ 16 kJ

66 kJ

Questions 36 of 50

Question:Standard molar enthalpy of formation of \(C{O_2}\) is equal to

Answers Choices:


The standard molar enthalpy of combustion of gaseous carbon

The sum of standard molar enthalpies of formation of \(CO\) and \({O_2}\)

The standard molar enthalpy of combustion of carbon (graphite)

Questions 37 of 50

Question:Ozone is prepared by passing silent electric discharge through oxygen. In this reaction

Answers Choices:

Energy is given out

Energy is absorbed

Oxygen is loaded with energy

Oxygen is dissociated into atoms

Questions 38 of 50

Question:Combustion of glucose takes place according to the equation, \({C_6}{H_{12}}{O_6} + 6{O_2} \to 6C{O_2} + 6{H_2}O\),\(\Delta H = - 72\,kcal\). How much energy will be required for the production of 1.6 g of glucose (Molecular mass of glucose = 180 g)

Answers Choices:

0.064 kcal

0.64 kcal

6.4 kcal

64 kcal

Questions 39 of 50

Question:Which of the following compounds will absorb the maximum quantity of heat when dissolved in the same amount of water ? The heats of solution of these compounds at \({25^o}C\) in kJ/mole of each solute is given in brackets

Answers Choices:

\(HN{O_3}(\Delta H = - 33)\)

\(KCl(\Delta H = + 17.64)\)

\(N{H_4}N{O_3}\,(\Delta H = + 25.5)\)

\(HCl\,(\Delta H = - 74.1)\)

Questions 40 of 50

Question:In the reaction \(C + 2S\, \to \,C{S_2} + \Delta H,\,\Delta H\) is the

Answers Choices:

Heat of combustion

Heat of neutralization

Heat of solution

None of these

Questions 41 of 50

Question:The heat evolved during the combination of 24 g C and 128 g S following the change is \(C + {S_2} \to C{S_2};\,\Delta H = 22.0\,kcal\)

Answers Choices:

11 kcal

32 kcal

44 kcal

22 kcal

Questions 42 of 50

Question:When the aqueous solution of 0.5 mole \(HN{O_3}\) is mixed with the 0.3 mole of \(O{H^ - }\) solution, then what will be the liberated heat (Enthalpy of neutralization is = 57.1 kJ)

Answers Choices:

28.5 kJ

17.1 kJ

45.7 kJ

1.7 kJ

Questions 43 of 50

Question:Enthalpy change for a reaction does not depend upon

Answers Choices:

The physical states of reactants and products

Use of different reactants for the same product

The nature of intermediate reaction steps

The differences in initial or final temperatures of involved substances

Questions 44 of 50

Question:\({C_{{\rm{dia}}}}\) + \({O_2} \to C{O_2};\) \(\Delta H = - 395.3\,kJ/mole\), \({C_{gr}} + {O_2} \to C{O_2};\,\Delta H = - 393.4\,kJ/mole\), \({C_{gr}} \to {C_{{\rm{dia}}}};\,\Delta H = \)

Answers Choices:





Questions 45 of 50

Question:The bond dissociation energy needed to form benzyl radical from toluene is ..... than the formation of the methyl radical from methane

Answers Choices:




None of the above

Questions 46 of 50

Question:Which one of the following bonds has the highest average bond energy (kcal/mol)

Answers Choices:

\(S = O\)

\(C \equiv C\)

\(C \equiv N\)

\(N \equiv N\)

Questions 47 of 50

Question:The dependence of Gibbs free energy on pressure for an isothermal process of an ideal gas is given by

Answers Choices:

\(\Delta {G_T} = nRT\,\ln \,\frac{{{P_2}}}{{{P_1}}}\)

\(\Delta {G_T} = nRT\,\ln \frac{{{V_2}}}{{{V_1}}}\)

\(\Delta {G_T} = nRT\,\log \,\frac{{{P_1}}}{{{P_2}}}\)

\(\Delta {G_T} = nRT\,\log \,\frac{{{V_2}}}{{{V_1}}}\)

Questions 48 of 50

Question:For the change \({H_2}O(l) \to {H_2}O(g);\,P = 1\,atm\), \(T = 373\,K\), the free energy change \(\Delta G = 0\). This indicates that

Answers Choices:

\({H_2}O(l)\) is in equilibrium with \({H_2}O(g)\)

Water boils spontaneously at \(373\,K\)

Water does not boil spontaneously at \(373\,K\)

Condensation of water vapour occurs spontaneously at \(373\,K\)

Questions 49 of 50

Question:Standard enthalpy and standard entropy changes for the oxidation of ammonia at \(298\,K\) are \( - 382.64\,kJ\,mo{l^{ - 1}}\) and \( - 145.6\,J{K^{ - 1}}mo{l^{ - 1}}\), respectively. Standard Gibbs energy change for the same reaction at \(298\,K\) is

Answers Choices:

439.3 kJ \(mo{l^{ - 1}}\)

523.2 \(kJ\,mo{l^{ - 1}}\)

221.1 \(kJ\,mo{l^{ - 1}}\)

339.3 \(kJ\,mo{l^{ - 1}}\)

Questions 50 of 50

Question:For spontaneity of a cell, which is correct

Answers Choices:

\(\Delta G = 0,\,\Delta E = 0\)

\(\Delta G = - ve,\,\Delta E = 0\)

\(\Delta G = + ve,\,\Delta E = + ve\)

\(\Delta G = - ve,\,\Delta E = + ve\)