Thermodynamics for Chemical Quiz 7

1 / 50

Pick out the wrong statement?

There is an increase in entropy, when a spontaneous change occurs in an isolated system

At absolute zero temperature, the heat capacity for many pure crystalline substances is zero

Cp of monatomic gases such as metallic vapor is about 5 kcal/kg.atom

The heat capacity of solid inorganic substance is exactly equal to the heat capacity of the substance in the molten state

2 / 50

The ammonia synthesis reaction represented by N2 + 3H2 ? 2NH3; ?H = ? 22.4 kcal, is___________?

Endothermic

Exothermic

Adiabatic

Isothermal

3 / 50

Standard temperature and pressure (S.T.P.) is___________?

15?C and 1 kgf/cm2

0?C and 1 kgf/cm2

15?C and 750 mm Hg

0?C and 750 mm Hg

4 / 50

Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400?C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg. K, entropy of saturated vapour = 7.2234 kJ/kg. K) The exit condition of steam is________?

Saturated vapour

Superheated vapour

Partially condensed vapour with quality of 0.9

Partially condensed vapour with quality of 0.1

5 / 50

Pick out the wrong statement ?

Heat of reaction at constant volume is equal to the change in internal energy

Clausius-Clapeyron equation is not applicable to melting process

Combustion reactions are never endothermic in nature

Enthalpies of all elements in their standard states are assumed to be zero

6 / 50

Reduced pressure of a gas is the ratio of its___________?

Pseudocritical pressure to pressure

Pressure to pseudocritical pressure

Pressure to critical pressure

Critical pressure to pressure

7 / 50

Pick out the wrong statement?

The eccentric factor for all materials is always more than one

Entropy of a system decreases with the evolution of heat

Surface tension of a substance vanishes at critical point, as there is no distinction between liquid and vapour phases at its critical point

Change of internal energy is negative for exothermic reactions

8 / 50

Sound waves propagation in air exemplifies an _______ process?

None of these

Adiabatic

Isothermal

Isometric

9 / 50

Rotary lime kiln is an example of a/an ______ system?

Non-thermodynamic

Open

Isolated

Closed

10 / 50

Refrigerants commonly used for domestic refrigerators are__________?

Ethyl chloride or methyl chloride

Propane

Freon-12

NH3 or CO2

11 / 50

Pick out the wrong statement ?

An isometric process is a constant pressure process

The expansion of a gas in vacuum is an irreversible process

Free energy change for a spontaneous process is negative

Entropy change for a reversible adiabatic process is zero

12 / 50

The activity of an ideal gas is numerically _____ its pressure?

Equal to

Less than

Data insufficient, can?t be predicted

More than

13 / 50

Pick out the wrong statement?

None of these

Nicotine-water system shows both an upper as well as a lower consolute temperature, implying that they are partially miscible between these two limiting temperatures

Systems, in which the mutual solubility increases with decrease in temperature, are said to possess lower consolute temperature

System (of partially miscible liquid pairs), in which the mutual solubility increases with rise in temperature, are said to possess an upper consolute temperature

14 / 50

Pick out the extensive property out of the following ?

Refractive index

Specific heat

Surface tension

Free energy

15 / 50

Pick out the correct statement?

A real gas on expansion in vacuum cools down whereas ideal gas remains unaffected

An ideal gas on expansion in vacuum gets heated up

A real gas on expansion in vacuum gets heated up

An ideal gas on expansion in vacuum gets cooled

16 / 50

PV? = Constant (where, ? = Cp/Cv) is valid for a/an _______ process?

Isothermal

Adiabatic

Isentropic

Isobaric

17 / 50

Specific ______ does not change during phase change at constant temperature and pressure?

Internal energy

Enthalpy

Gibbs energy

Entropy

18 / 50

Specific heat of a gas for a reversible adiabatic process is_________?

Zero

None of these

Negative

Infinity

19 / 50

Pick out the wrong statement?

The entropy of the universe tends to a maximum

The net change in entropy in any reversible cycle is always zero

The entropy of the system as a whole in an irreversible process increases

The entropy of a substance does not remain constant during a reversible adiabatic change

20 / 50

Pick out the wrong statement ?

At constant pressure, solubility of a gas in a liquid diminishes with rise in temperature

Normally, the gases which are easily liquefied are more soluble in common solvents

The gases which are capable of forming ions in aqueous solution are much more soluble in water than in other solvents

At constant pressure, solubility of a gas in a liquid increases with rise in temperature

21 / 50

Pick out the wrong statement pertaining to the decomposition of PCl5 represented by, PCl5 ? PCl3 + Cl2.Degree of dissociation of PCl5 will__________?

None of these

Increase on addition of an inert gas at constant pressure

Decrease on addition of Cl2

Decrease on increasing the pressure of the system

22 / 50

Pick out the undesirable property for a good refrigerant ?

High viscosity

Low freezing point

Large latent heat of vaporisation

High thermal conductivity

23 / 50

Refrigeration capacity of a household refrigerator may be round about ______ tons?

0.15

1.5

6.5

4.5

24 / 50

Pick out the wrong statement ?

The chemical potential of species ?i? in the mixture (?i) is mathematically represented as,?i = ?(nG)/?ni]T,P,nj where, n, ni and nj respectively denote the total number of moles, moles of ith species and all mole numbers except ith species. ?G? is Gibbs molar free energy

The chemical potential of a pure substance depends upon the temperature and pressure

The chemical potential of a component in a system is directly proportional to the escaping tendency of that component

The chemical potential of ith species (?i) in an ideal gas mixture approaches zero as the pressure or mole fraction (xi) tends to be zero at constant temperature

25 / 50

The absolute entropy for all crystalline substances at absolute zero temperature is ______?

Zero

More than zero

Indeterminate

Negative

26 / 50

Pick out the wrong statement?

One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW

A refrigeration cycle violates the second law of thermodynamics

Refrigeration cycle is normally represented by a temperature vs. entropy plot

In a refrigerator, work required decreases as the temperature of the refrigerator and the temperature at which heat is rejected increases

27 / 50

Second law of thermodynamics is concerned with the__________?

Non-cyclic processes only

Amount of energy transferred

Direction of energy transfer

Irreversible processes only

28 / 50

Solid and liquid phases of a substance are in equilibrium at the______?

Freezing point

Melting point

Both B. and C

Critical temperature

29 / 50

Pick out the wrong statement ?

Henry?s law is rigorously correct in the limit of infinite dilution

If Raoult?s law is applied to one component of a binary mixture; Henry?s law or Raoult?s law is applied to the other component also

An ideal liquid or solid solution is defined as one in which each component obeys Raoult?s law

None of these

30 / 50

Pick out the correct statement?

Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work

Otto engine efficiency decreases with the rise in compression ratio, due to decrease in work produced per quantity of heat

Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio

Compression ratio of an Otto engine is comparatively higher than a diesel engine

31 / 50

The amount of heat required to decompose a compound into its elements is ______ the heat of formation of that compound from its elements?

More than

Less than

Same as

Not related to

32 / 50

Refrigeration cycle__________?

Neither A. nor B

Violates second law of thermodynamics

Involves transfer of heat from low temperature to high temperature

Both A. and B

33 / 50

Pick out the wrong statement?

Heat transferred is equal to the change in the enthalpy of the system, for a constant pressure, non-flow, mechanically reversible process

Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures

The values of (?P/?V)T and (?2P/?V2)T are zero for a real gas at its critical point

During a reversible adiabatic process, the entropy of a substance remains constant

34 / 50

Sound waves propagation in air exemplifies an _______ process?

None of these

Isothermal

Adiabatic

Isometric

35 / 50

Pick out the wrong statement?

Thermal efficiency of a Carnot engine is always less than 1

Trouton?s ratio of non-polar liquids is calculated using Kistyakowsky equation

None of these

An equation relating pressure, volume and temperature of a gas is called ideal gas equation

36 / 50

Pick out the wrong statement ?

For a two phase system in equilibrium made up of four non-reacting chemical species, the number of degrees of freedom is 4

Minimum number of degree of freedom of a system is zero

Enthalpy and internal energy change is zero during phase change processes like melting, vaporisation and sublimation

Degree of freedom of a system containing a gaseous mixture of helium, carbon dioxide and hydrogen is 4

37 / 50

Pick out the correct statement?

If an insoluble gas is passed through a volatile liquid placed in a perfectly insulated container, the temperature of the liquid will increase

A process is irreversible as long as ? S for the system is greater than zero

The mechanical work done by a system is always equal to?P.dV

The heat of formation of a compound is defined as the heat of reaction leading to the formation of the compound from its reactants

38 / 50

Pick out the wrong statement__________?

Heat and work are both state function

CP and CV are state function

The work done by expansion of a gas in vacuum is zero

Phase rule variables are intensive properties

39 / 50

Pick out the correct statement?

Like internal energy and enthalpy, the absolute value of standard entropy for elementary substances is zero

The internal energy of an ideal gas depends only on its pressure

Melting of ice involves increase in enthalpy and a decrease in randomness

Maximum work is done under reversible conditions

40 / 50

Requisites of a reversible process is that the ______?

Friction in the system should be absent

System and surroundings pressure be equal

System and surroundings temperature be equal

None of these

41 / 50

Pressure-enthalpy chart is useful in refrigeration. The change in internal energy of an ideal fluid used in ideal refrigeration cycle is_______?

Negative

Zero

Infinity

Positive

42 / 50

Pick out the wrong statement ?

In a mixture of ideal gases, the fugacity of a component is equal to the partial pressure of the component.

In case of an ideal gas, the fugacity is equal to its pressure.

Activity co-efficient is dimensionless.

The fugacity co-efficient is zero for an ideal gas

43 / 50

Solubility of a substance which dissolves with an increase in volume and liberation of heat will be favoured by the________?

Low pressure and low temperature

High pressure and low temperature

Low pressure and high temperature

High pressure and high temperature

44 / 50

Specific/molar Gibbs free energy for a pure substance does not change during_________?

Sublimation

Melting

Either A, B. or C.

Vaporisation

45 / 50

Specific volume of an ideal gas is______?

Equal to its density

None of these

The reciprocal of its density

Proportional to pressure

46 / 50

The adiabatic throttling process of a perfect gas is one of constant enthalpy__________?

In which there is an increase in temperature

Which is exemplified by a non-steady flow expansion

Which can be performed in a pipe with a constriction

In which there is a temperature drop

47 / 50

Tea kept in a thermos flask is vigorously shaken. If the tea is considered as a system, then its temperature will__________?

First fall and then rise

Decrease

Increase

Remain unchanged

48 / 50

Pick out the correct statement?

The reversible work for compression in non-flow process under isothermal condition is the change in Helmholtz free energy

The available energy in an isolated system for all irreversible (real) processes decreases

All A, B. and C

The efficiency of a Carnot engine increases, if the sink temperature is decreased

49 / 50

Sublimation temperature of dry ice (solid CO2) is _____ ?C?

-273

-78

50 / 50

PVy = constant, holds good for an isentropic process, which is__________?

Reversible and adiabatic

Isothermal and irreversible

Reversible and isothermal

Adiabatic and irreversible

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