Thermochemistry and Thermodynamics Test 7

Total Questions:50 Total Time: 75 Min



Questions 1 of 50

Question:Any series of operations so carried out that at the end, the system is back to its initial state is called

Answers Choices:

Boyle's cycle

Reversible process

Adiabatic process

Cyclic process

Questions 2 of 50

Question:One calorie is equal to

Answers Choices:

0.4184 Joule

4.184 Joule

41.84 Joule

418.4 Joule

Questions 3 of 50

Question:In an isochoric process the increase in internal energy is

Answers Choices:

Equal to the heat absorbed

Equal to the heat evolved

Equal to the work done

Equal to the sum of the heat absorbed and work done

Questions 4 of 50

Question:It is general principle that the less energy a system contains, it is

Answers Choices:

Less stable

More stable


More unstable

Questions 5 of 50

Question:For the reaction of one mole of zinc dust with one mole of sulphuric acid in a bomb calorimeter, \(\Delta {\rm{U}}\) and w correspond to

Answers Choices:

\(\Delta {\rm{U}} < 0,\;w = 0\)

\(\Delta {\rm{U}} = 0,\;w < 0\)

\(\Delta {\rm{U}} > 0,\;w = 0\)

\(\Delta {\rm{U}} < 0,\;w > 0\)

Questions 6 of 50

Question:Which is not the correct relation between enthalpy \((\Delta H)\)and intrinsic energy \((\Delta E)\)

Answers Choices:

\(\Delta H = \Delta E + \,P\,\Delta V\)

\(\Delta H\, = \,\Delta E\, + \,n\,RT\)

\(\Delta H = \Delta E\, - \,P\,\Delta V\)

\(\Delta E = \Delta H\, - \,P\,\Delta V\)

Questions 7 of 50

Question:Which of the following expressions represents the first law of thermodynamics

Answers Choices:

\(\Delta E = - q + W\)

\(\Delta E = q - W\)

\(\Delta E = q + W\)

\(\Delta E = - q - W\)

Questions 8 of 50

Question:In a reversible isothermal process, the change in internal energy is

Answers Choices:




None of these

Questions 9 of 50

Question:The value of \(\Delta H - \Delta E\) for the following reaction at \({27^o}C\) will be \(2N{H_3}(g)\, \to \,{N_2}(g) + 3{H_2}(g)\)

Answers Choices:

\(8.314 \times 273 \times ( - 2)\)

\(8.314 \times 300 \times ( - 2)\)

\(8.314 \times 27 \times ( - 2)\)

\(8.314 \times 300 \times (2)\)

Questions 10 of 50

Question:For which of the following \(\Delta E = \Delta H\)

Answers Choices:

\({N_2}{O_4}(g)\) \( \leftrightarrow \) \(2N{O_2}(g)\)

\(2S{O_2}(g) + {O_2}(g)\) \( \leftrightarrow \) \(2S{O_3}(g)\)

\({H_2}(g) + C{l_2}(g)\) \( \leftrightarrow \) \(2HCl(g)\)

\({H_2}(g) + \frac{1}{2}{O_2}(g)\) \( \leftrightarrow \) \({H_2}O(l)\)

Questions 11 of 50

Question:Internal energy is

Answers Choices:

Partly potential and partly kinetic

Totally kinetic

Totally potential

None of these

Questions 12 of 50

Question:For which of the reaction \(\Delta H = \Delta E\)

Answers Choices:

\({N_2} + 3{H_2}\)\( \leftrightarrow \)\(2N{H_3}\)

\({N_2} + {O_2} \to 2NO\)

\(2Na + C{l_2} \to 2NaCl\)

\(PC{l_5} \to PC{l_3} + C{l_2}\)

Questions 13 of 50

Question:Which of the following pairs of a chemical reaction is certain to result in spontaneous reaction ?

Answers Choices:

Exothermic and decreasing disorder

Endothermic and increasing disorder

Exothermic and increasing disorder

Endothermic and decreasing disorder

Questions 14 of 50

Question:When one mole of monoatomic ideal gas at T K undergoes adiabatic change under a constant external pressure of 1 atm changes volume from 1 litre to 2 litre. The final temperature in Kelvin would be

Answers Choices:


T + \(\frac{2}{{3 \times 0.0821}}\)


T - \(\frac{2}{{3 \times 0.0821}}\)

Questions 15 of 50

Question:9.0 gm of \({H_2}O\) is vaporised at \({100^o}C\) and 1 atm pressure. If the latent heat of vaporisation of water is \(x\,J/gm\), then \(\Delta S\) is given by

Answers Choices:




\(\frac{1}{2} \times \frac{{18x}}{{373}}\)

Questions 16 of 50

Question:The positive value of \(\Delta S\) indicates that

Answers Choices:

The system becomes less disordered

The system becomes more disordered

The system is in equilibrium position

The system tends to reach at equilibrium position

Questions 17 of 50

Question:For reaction \(2Cl(s) \to C{l_2}(s)\), the signs of \(\Delta H\) and \(\Delta S\) respectively are

Answers Choices:

+, –

+, +

, –

, +

Questions 18 of 50

Question:The enthalpy of water is \(386\,kJ\). What is entropy of water

Answers Choices:

0.5 kJ

1.03 kJ

1.5 kJ

22.05 kJ

Questions 19 of 50

Question:Which of the following endothermic processes are spontaneous

Answers Choices:

Melting of ice

Evaporation of water

Heat of combustion

Both and

Questions 20 of 50

Question:For the reaction \({H_2}O(s)\) \( \leftrightarrow \) \({H_2}O(l)\) at \({0^o}C\) and normal pressure

Answers Choices:

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

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

\(\Delta H = \Delta G\)

\(\Delta H < T\Delta S\)

Questions 21 of 50

Question:One mole of an ideal gas is allowed to expand reversibly and adiabatically from a temperature of \({27^o}C\). If the work done during the process is 3 kJ, the final temperature will be equal to \(({C_v} = 20\,J{K^{ - 1}})\)

Answers Choices:

150 K

100 K


295 K

Questions 22 of 50

Question:For a carnot engine, the source is at \(500K\) and the sink at \(300K\). What is efficiency of this engine

Answers Choices:





Questions 23 of 50

Question:Heat require to raise the temperature of 1 mol of a substance by \({1^o}C\) is called

Answers Choices:

Specific heat

Molar heat capacity

Water equivalent

Specific gravity

Questions 24 of 50

Question:Maximum entropy will be in which of the following

Answers Choices:


Liquid water


Water vapours

Questions 25 of 50

Question:An exothermic reaction is one in which the reacting substances

Answers Choices:

Have more energy than the products

Have less energy than the products

Are at a higher temperature than the product

None of the above

Questions 26 of 50

Question:The heat evolved in the combustion of benzene is given by \({C_6}{H_6} + 7\frac{1}{2}{O_2} \to 6C{O_2}(g) + 3{H_2}O(l);\,\Delta H = - 3264.6\,kJ\) . Which of the following quantities of heat energy will be evolved when \(39\,g\,{C_6}{H_6}\) are burnt

Answers Choices:

816.15 kJ

1632.3 kJ

6528.2 kJ

2448.45 kJ

Questions 27 of 50

Question:Enthalpy change for reaction, \(\frac{1}{2}{H_2} + \frac{1}{2}C{l_2} \to HCl\), is called

Answers Choices:

Enthalpy of combination

Enthalpy of reaction

Enthalpy of formation

Enthalpy of fusion

Questions 28 of 50

Question:The enthalpy of neutralization is about 57.3 kJ for the pair

Answers Choices:

\(HCl\) and \(N{H_4}OH\)

\(N{H_4}OH\) and \(HN{O_3}\)

\(HCl\) and \(NaOH\)

\(C{H_3}COOH\) and \(NaOH\)

Questions 29 of 50

Question:The heat change for the reaction \({H_2} + \frac{1}{2}{O_2} \to {H_2}O\) is called

Answers Choices:

Heat of reaction

Heat of formation

Heat of vaporization

None of the above

Questions 30 of 50

Question:The heat change \(\Delta H\) for the reaction \(2CO + {O_2} \to 2C{O_2};\,\Delta H = - 135\,kcal\) is called

Answers Choices:

Heat of formation

Heat of reaction

Heat of combustion

Heat of solution

Questions 31 of 50

Question:The heat of formation is the change in enthalpy accompanying the formation of a substance from its elements at 298 K and 1 atm pressure. Since the enthalpies of elements are taken to be zero, the heat of formation \((\Delta H)\) of compounds

Answers Choices:

Is always negative

Is always positive

May be negative or positive

Is zero

Questions 32 of 50

Question:The heat of combustion of \(C{H_{4(g)}},\,{C_{({\rm{graphite}})}}\) and \({H_{2(g)}}\) are \(20\,kcal,\, - 40\,kcal\) and \( - 10\,kcal\) respectively. The heat of formation of methane is

Answers Choices:

\( - 4.0\,kcal\)

\( + 40\,kcal\)

\( - 80\,kcal\)

\( + 80\,kcal\)

Questions 33 of 50

Question:\(C\)(diamond) \( + {C_2}(g) \to C{O_2}(g);\,\Delta H = - 395\) kJ \(C\) (graphite) \( + {O_2}(g) \to C{O_2}(g);\,\Delta H = - 393.5\) kJ . From the data, the \(\Delta H\) when diamond is formed from graphite, is

Answers Choices:

\( - 1.5\,kJ\)

\( + \,1.5\,kJ\)

\( + \,3.0\,kJ\)

\( - 3.0\,kJ\)

Questions 34 of 50

Question:Which of the following values of heat of formation indicates that the product is least stable

Answers Choices:

\( - 94\,kcal\)

\( - \,231.6\,kcal\)

\( + 21.4\,kcal\)

\( + \,64.8\,kcal\)

Questions 35 of 50

Question:In an exothermic reaction \(\Delta H\) is

Answers Choices:




Both positive or negative

Questions 36 of 50

Question:The heat change for the following reaction \(C(s) + 2S(s) \to C{S_2}(l)\) is known as

Answers Choices:

Heat of vaporization

Heat of solution

Heat of fusion

Heat of formation

Questions 37 of 50

Question:The enthalpy of solution of \(BaC{l_2}(s)\) and \(BaC{l_2}.2{H_2}O(s)\) are \( - 20.6\) and \(8.8\,kJ\,mo{l^{ - 1}}\) respectively. The enthalpy change for the reaction \(BaC{l_2}(s) + 2{H_2}O \to \) is

Answers Choices:

29.4 kJ

11.8 kJ

20.6 kJ

29.4 kJ

Questions 38 of 50

Question:The enthalpy change of a reaction does not depend on

Answers Choices:

The state of reactants and products

Nature of reactants and products

Different intermediate reaction

Initial and final enthalpy change of a reaction

Questions 39 of 50

Question:In the reaction: \({H_2} + C{l_2}\, \to \,2HCl,\,\Delta H = 194\,kJ\). Heat of formation of \(HCl\) is

Answers Choices:

+ 97 kJ

+ 194 kJ

194 kJ

97 kJ

Questions 40 of 50

Question:Enthalpy of neutralisation of acetic acid by \(NaOH\) is \( - 50.6\,kJ/mol.\) and the heat of neutralisation of a strong acid with a strong base is -55.9 kJ/mol. What is the value of \(\Delta H\) for the ionisation of \(C{H_3}COOH\)

Answers Choices:

+ 5.3 kJ/mol

+ 6.2 kJ/mol

+ 8.2 kJ/mol

+ 9.3 kJ/mol

Questions 41 of 50

Question:The values of \(\Delta H\) for the combustion of ethene and ethyne are -341.1 and -310.0kcal respectively. Which of the following is a better fuel

Answers Choices:



Both of these

None of these

Questions 42 of 50

Question:For exothermic reaction, the equilibrium constant

Answers Choices:

Increases with increase of P

Decreases with increase of P

Increases with increase of temperature

Decreases with increase of temperature

Questions 43 of 50

Question:If a mole of \({H_2}\) molecule is heated to high temperature the following reaction takes place

Answers Choices:

\({H_2}(g) + 436\,kJ = H(g) + H(g)\)

\({H_2}(g) + 820\,kJ = 2{H_2}(g)\)

\(2{H_2}(g) + 436\,J = 2{H_2}\)

\({H_2} + {H_2} = {H^ + } + {H^ + }\)

Questions 44 of 50

Question:Which of the following reactions is not exothermic

Answers Choices:

\(C(s) + {O_2}(g)\, \to \,C{O_2}(g)\)

\(C(s) + 2S(s)\, \to \,C{S_2}(g)\)

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

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

Questions 45 of 50

Question:The enthalpy of combustion of methane at \({25^o}C\) is \(890\,kJ\). The heat liberated when \(3.2\,g\) of methane is burnt in air is

Answers Choices:



\( - 890\,kJ\)


Questions 46 of 50

Question:If (i) \(C + {O_2} \to C{O_2}\), (ii) \(C + 1/2{O_2} \to CO\), (iii) \(CO + 1/2{O_2} \to C{O_2}\), the heats of reaction are \(Q,\, - 12,\, - 10\) respectively. Then \(Q = \)

Answers Choices:





Questions 47 of 50

Question:For a spontaneous change, free energy change \(\Delta G\) is

Answers Choices:




Can be positive or negative

Questions 48 of 50

Question:A minus sign of the free energy change denotes that

Answers Choices:

The reaction tends to proceed spontaneously

The reaction is non-spontaneous

The system is in equilibrium

The reaction is very much unlikely

Questions 49 of 50

Question:The essential condition for the feasibility of a reaction is that

Answers Choices:

The reaction should be exothermic

The entropy of products must be larger than that of reactants

The reaction is to be accompanied with free energy decrease

The reaction has to possess high activation energy

Questions 50 of 50

Question:The correct relationship between free energy change in a reaction and the corresponding equilibrium constant \({K_c}\) is

Answers Choices:

\(\Delta G = RT\ln {K_c}\)

\( - \Delta G = RT\ln {K_c}\)

\(\Delta {G^o} = RT\ln {K_c}\)

\( - \Delta {G^o} = RT\ln {K_c}\)