# Thermochemistry and Thermodynamics Test 6

Total Questions:50 Total Time: 75 Min

Remaining:

## Questions 1 of 50

Question:Internal energy of an ideal gas depends on

Volume

Temperature

Pressure

None of these

## Questions 2 of 50

Question:Point out the wrong statement in relation to enthalpy

It is a state function

It is an intensive property

It is independent of the path followed for the change

Its value depends upon the amount of substance in the system

## Questions 3 of 50

Question:Which of the following is zero for an isochoric process

$$dP$$

$$dV$$

$$dT$$

$$dE$$

## Questions 4 of 50

Question:Mark the correct statement

For a chemical reaction to be feasible, $$\Delta G$$ should be zero

Entropy is a measure of order in a system

For a chemical reaction to be feasible, $$\Delta G$$ should be positive

The total energy of an isolated system is constant

## Questions 5 of 50

Question:Which of the following is always negative for exothermic reaction?

$$\Delta H$$

$$\Delta \Sigma$$

$$\Delta \Gamma$$

None of these

## Questions 6 of 50

Question:The relation between $$\Delta E$$ and $$\Delta H$$ is

$$\Delta H = \Delta E - P\,\Delta V$$

$$\Delta H = \Delta E + P\,\Delta V$$

$$\Delta E = \Delta V + \Delta H$$

$$\Delta E = \Delta H + P\,\Delta V$$

## Questions 7 of 50

Question:At constant T and P, which one of the following statements is correct for the reaction, $$CO(g) + \frac{1}{2}{O_2}(g) \to C{O_2}(g)$$

$$\Delta H$$ is independent of the physical state of the reactants of that compound

$$\Delta H\, > \,\Delta E$$

$$\Delta H\, < \,\Delta E$$

$$\Delta H = \Delta E$$

## Questions 8 of 50

Question:The law of conservation of energy states that

The internal energy of a system is constant

The heat content of a system is constant

Energy is neither created nor destroyed

There is an equivalence between energy and mass

## Questions 9 of 50

Question:The enthalpies of the elements in their standard states are assumed to be

Zero at 298 K

Unit at 298 K

Zero at all temperatures

Zero at 273 K

## Questions 10 of 50

Question:The heat $$Q$$ for a reaction at constant volume is equal to

$${H_P} - {H_R}$$

$${H_R} - {H_P}$$

$${E_P} - {E_R}$$

None of these

## Questions 11 of 50

Question:Hess law is based on

Law of conservation of mass

Law of conservation of energy

Enthalpy is a state function

None of these

## Questions 12 of 50

Question:For the reaction, $${C_3}{H_8}(g) + 5{O_2}(g) \to \,\,3C{O_2}(g) + 4{H_2}O(l)$$ at constant temperature, $$\Delta H - \Delta E$$ is

RT

+ RT

3RT

+ 3RT

## Questions 13 of 50

Question:According to Hess's law, the heat of reaction depends upon

Initial condition of reactants

Initial and final conditions of reactants

Intermediate path of the reaction

End conditions of reactants

## Questions 14 of 50

Question:For the gaseous reaction, $${N_2}{O_4} \to 2N{O_2}$$

$$\Delta H < \Delta E$$

$$\Delta H = \Delta E$$

$$\Delta H = 0$$

$$\Delta H > \Delta E$$

## Questions 15 of 50

Question:$$2C + {O_2} \to 2CO;\,\,\Delta H = - 220\,kJ$$. Which of the following statement is correct for this reaction

Heat of combustion of carbon is 110 kJ

Reaction is exothermic

Reaction needs no initiation

All of these are correct

## Questions 16 of 50

Question:An ideal gas expands in volume from $$1 \times {10^{ - 3}}{m^3}$$ to $$1 \times {10^{ - 2}}{m^3}$$ at 300 K against a constant pressure of $$1 \times {10^5}N{m^{ - 2}}$$. The work done is

270 kJ

900 kJ

900 J

900 kJ

## Questions 17 of 50

Question:The entropy of crystalline substances at absolute zero going by the third law of thermodynamics should be taken as

100

50

Zero

Different for different substances

## Questions 18 of 50

Question:In which state, the matter have highest entropy

Solid

Liquid

Gas

Equal in all

## Questions 19 of 50

Question:When a solid is converted into liquid, entropy

Becomes zero

Remains the same

Decreases

Increases

## Questions 20 of 50

Question:In a spontaneous process, the entropy of the system and its surroundings

Equals zero

Decreases

Increases

Remains constant

## Questions 21 of 50

Question:The volume of a gas decreases from $$500\,cc$$ to $$300\,cc$$ when a sample of gas is compressed by an average pressure of 0.6 atm. During this process 10 J of heat is liberated. The change in internal energy is

2.16 J

12.156 J

2.16 J

101.3 J

## Questions 22 of 50

Question:The standard entropies of $$C{O_2}(g),\,C(s)$$ and $${O_2}(g)$$ are 213.5, 5.690 and $$205\,J{K^{ - 1}}$$ respectively. The standard entropy of formation of $$C{O_2}(g)$$ is

$$1.86\,J{K^{ - 1}}$$

$$1.96\,J{K^{ - 1}}$$

$$2.81\,J{K^{ - 1}}$$

$$2.86\,J{K^{ - 1}}$$

## Questions 23 of 50

Question:Standard entropy change for the above reaction is

$$60.3\,J{K^{ - 1}}mo{l^{ - 1}}$$

$$80.7\,J{K^{ - 1}}mo{l^{ - 1}}$$

$$- 70\,J{K^{ - 1}}mo{l^{ - 1}}$$

$$+ 10.7\,J{K^{ - 1}}mo{l^{ - 1}}$$

## Questions 24 of 50

Question:One mole of water at $${100^o}C$$ is converted into steam at $${100^o}C$$ at a constant pressure of 1 atm. The change in entropy is [heat of vaporisation of water at $${100^o}C = 540\,cal/gm$$]

8.74

18.76

24.06

26.06

## Questions 25 of 50

Question:From Kirchhoff's equation which factor affects the heat of reaction

Pressure

Temperature

Volume

Molecularity

## Questions 26 of 50

Question:The molar neutralization heat for $$KOH$$ and $$HN{O_3}$$ as compared to molar neutralization heat of $$NaOH$$ and $$HCl$$

Less

More

Equal

Depends on pressure

## Questions 27 of 50

Question:If the enthalpy of B is greater than of A, the reaction $$A \to B$$ is

Endothermic

Exothermic

Instantaneous

Spontaneous

## Questions 28 of 50

Question:Given that $$2C(s) + 2{O_2}(g) \to 2C{O_2}(g);\,\,\Delta H = - 787\,kJ$$, $${H_2}(g) + \frac{1}{2}{O_2}(g) \to {H_2}O(l);\,\,\Delta H = - 286\,kJ$$ , $${C_2}{H_2}(g) + 2\frac{1}{2}{O_2}(g) \to 2C{O_2}(g) + {H_2}O(l);\,\Delta H = - 1301\,kJ$$, Heat of formation of acetylene is

$$- \,1802\,kJ$$

$$+ \,1802\,kJ$$

$$- 800\,kJ$$

$$+ 228\,kJ$$

## Questions 29 of 50

Question:In the reaction $$C{O_2}(g) + {H_2}(g) \to CO(g) + {H_2}O(g);\,\Delta H = 80\,kJ$$ $$\Delta H$$ is known as

Heat of formation

Heat of combustion

Heat of neutralization

Heat of reaction

## Questions 30 of 50

Question:Heat of combustion of a substance

Is always positive

Is always negative

Is equal to heat of formation

Nothing can be said without reaction

## Questions 31 of 50

Question:Reaction, $${H_2}(g) + {I_2}(g) \to 2HI(g)$$ $$\Delta H = - 12.40\,kcal$$. According to this, the heat of formation of HI will be

12.4 kcal

12.4 kcal

6.20 kcal

6.20 kcal

## Questions 32 of 50

Question:All reactions with chemical dissociation are

Reversible

Reversible and endothermic

Exothermic

Reversible or irriversible and endothermic or exothermic

## Questions 33 of 50

Question:The standard heats of formation in kcal $$mo{l^{ - 1}}$$ of $$N{O_2}(g)$$ and $${N_2}{O_4}(g)$$ are 8.0 and 2.0 respectively. The heat of dimerization of $$N{O_2}$$ in $$kcal$$ is $$2N{O_2}(g) = {N_2}{O_4}(g)$$

10

6.0

12.0

14.0

## Questions 34 of 50

Question:The difference between heats of reaction at constant pressure and at constant volume for the reaction $$2{C_6}{H_6}(l) + 15{O_2}(g) \to 12C{O_2}(g) + 6{H_2}O(l)$$at $${25^o}C$$in kJ is

7.43

3.72

3.72

7.43

## Questions 35 of 50

Question:Heat of formation in the reaction $${H_2} + C{l_2} \to 2HCl + 44\,kcal$$ is

44 kcal

44000 kcal

22 kcal

11 kcal

## Questions 36 of 50

Question:When water is added to quick lime, the reaction is

Exothermic

Endothermic

Explosive

None of these

## Questions 37 of 50

Question:$$8\,gm$$ of $$C{H_4}$$ is completely burnt in air. The number of moles of water produced are

0.5

1

2

18

## Questions 38 of 50

Question:For the reaction $$A(g) + 2B(g) \to 2C(g) + 3D(g)$$, the value of $$\Delta E$$ at $${27^o}C$$ is 19.0 kcal. The value of $$\Delta H$$ for the reaction would be $$(R = 2.0\,cal\,{K^{ - 1}}mo{l^{ - 1}})$$

20.8 kcal

19.8 kcal

18.8 kcal

20.2 kcal

## Questions 39 of 50

Question:When a strong acid, strong base or their salt are dissolved in water, they are completely ionised. If a strong acid is added to a strong base, $${H^ + }$$ ions from the former combine with $$O{H^ - }$$ ions of the latter forming water. The formation of each water molecule liberates a certain quantity of energy and the reaction is exothermic. The heat liberated when one mole of water is formed by combining hydrochloric acid and sodium hydroxide is 13.7 kcal. The heat liberated when one mole of water is formed by combining sulphuric acid and sodium hydroxide is

25.5 kcal

8.5 kcal

13.7 kcal

34 kcal

## Questions 40 of 50

Question:2.1 g of Fe combines with S evolving 3.77 kJ. The heat of formation of FeS in kJ/mol is

1.79

100.5

3.77

None of these

## Questions 41 of 50

Question:If the heat of combustion of carbon monoxide at constant volume and at $${17^o}C$$ is – 283.3 kJ, then its heat of combustion at constant pressure $$(R = 8.314\,J\,{\rm{degre}}{{\rm{e}}^{{\rm{ - 1}}}}mo{l^{ - 1}})$$

284.5 kJ

284.5 kJ

384.5 kJ

384.5 kJ

## Questions 42 of 50

Question:Heat of formation of $${H_2}O$$ is $$- 188\,kJ/mole$$ and $${H_2}{O_2}$$ is $$- 286\,kJ/mole.$$ The enthalpy change for the reaction $$2{H_2}{O_2}\, \to \,2{H_2}O + {O_2}$$ is

196 kJ

196 kJ

984 kJ

984 kJ

## Questions 43 of 50

Question:Enthalpy of neutralisation of $$N{H_4}OH$$ and $$HCl$$, is numerically

$$57.1\,\,kJ\,mo{l^{ - 1}}$$

$$< 57.1\,\,kJ\,mo{l^{ - 1}}$$

$$> 57.1\,\,kJ\,mo{l^{ - 1}}$$

Zero

## Questions 44 of 50

Question:The heat of neutralisation will be highest in

$$N{H_4}OH$$ and $$C{H_3}COOH$$

$$N{H_4}OH$$ and $$HCl$$

$$KOH$$ and $$C{H_3}COOH$$

$$KOH$$ and $$HCl$$

## Questions 45 of 50

Question:Which of the following pairs has heat of neutralisation equal to 13.7 Kcals

$$HCl,\,N{H_4}OH$$

$$HN{O_3},\,KOH$$

$$NaOH,\,C{H_3}COOH$$

$${H_2}S{O_4},\,N{H_4}OH$$

## Questions 46 of 50

Question:The enthalpies of combustion of carbon and carbon monodie are -393.5 and -283 kJ mol$$^{ - 1}$$ respectivley. The enthalpy of formation of carbon monoxide per mole is

$$- 676.5\,kJ$$

$$676.5\,kJ$$

$$110.5\,kJ$$

$$- 110.5\,kJ$$

## Questions 47 of 50

Question:If the bond energies of $$H - H$$, $$Br - Br$$ and $$HBr$$ are 433, 192 and 364 $$kJ\,mo{l^{ - 1}}$$ respectively, the $$\Delta {H^o}$$ for the reaction, $${H_2}(g) + B{r_2}(g) \to 2HBr(g)$$ is

+ 261 kJ

103 kJ

261 kJ

+ 103 kJ

## Questions 48 of 50

Question:The free energy change for a reversible reaction at equilibrium is

Large positive

Small negative

Small positive

0

## Questions 49 of 50

Question:Born-Haber cycle is used to determine

Crystal energy

Electron affinity

Lattice energy

All of these

## Questions 50 of 50

Question:Gibbs free energy G, enthalpy H and entropy S are interrelated as in

$$G = H + TS$$
$$G = H - TS$$
$$G - TS = H$$
$$G = S = H$$