# Thermochemistry and Thermodynamics Test 7

Total Questions:50 Total Time: 75 Min

Remaining:

## 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

Boyle's cycle

Reversible process

Cyclic process

## Questions 2 of 50

Question:One calorie is equal to

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

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

Less stable

More stable

Unstable

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

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

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

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

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

## Questions 6 of 50

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

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

$$\Delta H\, = \,\Delta E\, + \,n\,RT$$

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

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

## Questions 7 of 50

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

$$\Delta E = - q + W$$

$$\Delta E = q - W$$

$$\Delta E = q + W$$

$$\Delta E = - q - W$$

## Questions 8 of 50

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

Zero

Positive

Negative

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 $$2N{H_3}(g)\, \to \,{N_2}(g) + 3{H_2}(g)$$

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

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

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

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

## Questions 10 of 50

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

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

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

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

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

## Questions 11 of 50

Question:Internal energy is

Partly potential and partly kinetic

Totally kinetic

Totally potential

None of these

## Questions 12 of 50

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

$${N_2} + 3{H_2}$$$$\leftrightarrow$$$$2N{H_3}$$

$${N_2} + {O_2} \to 2NO$$

$$2Na + C{l_2} \to 2NaCl$$

$$PC{l_5} \to PC{l_3} + C{l_2}$$

## Questions 13 of 50

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

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

$$\frac{T}{{{2^{(2/3)}}}}$$

T + $$\frac{2}{{3 \times 0.0821}}$$

T

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

$$\frac{x}{{373}}$$

$$\frac{{18x}}{{100}}$$

$$\frac{{18x}}{{373}}$$

$$\frac{1}{2} \times \frac{{18x}}{{373}}$$

## Questions 16 of 50

Question:The positive value of $$\Delta S$$ indicates that

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

+, –

+, +

, –

, +

## Questions 18 of 50

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

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

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

$$\Delta H > T\Delta S$$

$$\Delta H = T\Delta S$$

$$\Delta H = \Delta G$$

$$\Delta H < T\Delta S$$

## 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 $$({C_v} = 20\,J{K^{ - 1}})$$

150 K

100 K

$${26.85^o}C$$

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

0.2

0.4

0.6

0.3

## Questions 23 of 50

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

Specific heat

Molar heat capacity

Water equivalent

Specific gravity

## Questions 24 of 50

Question:Maximum entropy will be in which of the following

Ice

Liquid water

Snow

Water vapours

## Questions 25 of 50

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

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

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

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

$$HCl$$ 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

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

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

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

$$- 4.0\,kcal$$

$$+ 40\,kcal$$

$$- 80\,kcal$$

$$+ 80\,kcal$$

## 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

$$- 1.5\,kJ$$

$$+ \,1.5\,kJ$$

$$+ \,3.0\,kJ$$

$$- 3.0\,kJ$$

## Questions 34 of 50

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

$$- 94\,kcal$$

$$- \,231.6\,kcal$$

$$+ 21.4\,kcal$$

$$+ \,64.8\,kcal$$

## Questions 35 of 50

Question:In an exothermic reaction $$\Delta H$$ is

Positive

Negative

Zero

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

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

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

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

+ 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 $$C{H_3}COOH$$

+ 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

$${C_2}{H_2}$$

$${C_2}{H_4}$$

Both of these

None of these

## Questions 42 of 50

Question:For exothermic reaction, the equilibrium constant

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

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

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

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

$${H_2} + {H_2} = {H^ + } + {H^ + }$$

## Questions 44 of 50

Question:Which of the following reactions is not exothermic

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

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

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

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

## 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

$$445\,kJ$$

$$278\,kJ$$

$$- 890\,kJ$$

$$178\,kJ$$

## 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 $$Q =$$

2

2

22

16

## Questions 47 of 50

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

Positive

Negative

Zero

Can be positive or negative

## Questions 48 of 50

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

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

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

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