Chemical Reaction Thermodynamics - Aiza Flashcards
Maximum work that could be secured by expanding the gas over a given pressure range is the __________ work.
a. isothermal
b. adiabatic
c. isentropic
d. none of these
a. isothermal
Internal energy change of a system over one complete cycle in a cyclic process is
a. zero
b. +ve
c. -ve
d. dependent on the path
a. zero
Heating of water under atmospheric pressure is an __________ process.
a. isochoric
b. isobaric
c. adiabatic
d. isothermal
b. isobaric
Van Laar equation deals with the activity co-efficients in
a. binary solutions
b. ternary solutions
c. azeotropic mixture only
d. none of these
a. binary solutions
High __________ is an undesirable property for a good refrigerant.
a. specific heat
b. latent heat of vaporisation
c. viscosity
d. specific vapor volume
c. viscosity
Solubility of a substance which dissolves with an increase in volume and liberation of heat will be favoured by the
a. low pressure and high temperature.
b. low pressure and low temperature.
c. high pressure and low temperature.
d. high pressure and high temperature.
b. low pressure and low temperature.
Entropy is a measure of the __________ of a system.
a. disorder
b. orderly behaviour
c. temperature changes only
d. none of these
a. disorder
A chemical reaction will occur spontaneously at constant pressure and temperature, if the free energy is
a. zero
b. positive
c. negative
d. none of these
c. negative
Fundamental principle of refrigeration is based on the __________ law of thermodynamics.
a. zeroth
b. first
c. second
d. third
c. second
For a spontaneous process, free energy
a. is zero
b. increases
c. decreases whereas the entropy increases
d. and entropy both decrease
c. decreases whereas the entropy increases
A refrigeration cycle is a reversed heat engine. Which of the following has the maximum value of the co-efficient of performance (COP) for a given refrigeration effect ?
a. Vapor compression cycle using expansion valve.
b. Air refrigeration cycle.
c. Vapor compression cycle using expansion engine.
d. Carnot refrigeration cycle.
d. Carnot refrigeration cycle.
In a working refrigerator, the value of COP is always
a. 0
b. < 0
c. < 1
d. >1
d. >1
__________ increases with increase in pressure.
a. The melting point of wax
b. The boiling point of a liquid
c. both (a) and (b)
d. neither (a) nor (b)
c. both (a) and (b)
A refrigerator may be termed as a
a. heat pump
b. heat engine
c. Carnot engine
d. none of these
a. heat pump
For a stable phase at constant pressure and temperature, the fugacity of each component in a binary system __________ as its mole fraction increases.
a. decreases
b. increases
c. remains same
d. decreases linearly
b. increases
Which of the following is not an intensive property ?
a. Chemical potential
b. Surface tension
c. Heat capacity
d. None of these
c. Heat capacity
Out of the following refrigration cycles, which one has the minimum COP (Co-efficient of performance)?
a. Air cycle
b. Carnot cycle
c. Ordinary vapour compression cycle
d. Vapour compression with a reversible expansion engine
a. Air cycle
Measurement of thermodynamic property of temperature is facilitated by __________ law of thermodynamics.
a. 1st
b. zeroth
c. 3rd
d. none of these
b. zeroth
The theoretical minimum work required to separate one mole of a liquid mixture at 1 atm, containing 50 mole % each of n- heptane and n- octane into pure compounds each at 1 atm is
a. -2 RT ln 0.5
b. -RT ln 0.5
c. 0.5 RT
d. 2 RT
b. -RT ln 0.5
Keeping the pressure constant, to double the volume of a given mass of an ideal gas at 27°C, the temperature should be raised to __________ °C.
a. 270
b. 327
c. 300
d. 540
b. 327
Entropy of an ideal gas depends upon its
a. pressure
b. temperature
c. both (a) & (b)
d. neither (a) nor (b)
c. both (a) & (b)
Isobaric process means a constant process.
a. temperature
b. pressure
c. volume
d. entropy
b. pressure
No work is done by the system, when a reaction occurs at constant
a. volume
b. temperature
c. pressure
d. none of these
a. volume
If the vapour pressure at two temperatures of a solid phase in equilibrium with its liquid phase are known, then the latent heat of fusion can be calculated by the
a. Maxwell’s equation
b. Clayperon-Clausius equation
c. Van Laar equation
d. Nernst Heat Theorem
b. Clayperon-Clausius equation
The freezing point of a liquid decreases when the pressure is increased, if the liquid __________ while freezing.
a. contracts
b. expands
c. does not change in volume
d. either (a), (b) or (c)
a. contracts
“At the absolute zero temperature, the entropy of every perfectly crystalline substance becomes zero”. This follows from the
a. third law of thermodynamics
b. second law of thermodynamics
c. Nernst heat theorem
d. Maxwell’s relations
a. third law of thermodynamics
During Joule-Thomson expansion of gases (Page 2-182)
a. enthalpy remains constant.
b. entropy remains constant.
c. temperature remains constant.
d. none of these.
a. enthalpy remains constant.
The accentric factor of a materical, ‘ω’, is defined as ω = -log10(Prsat)Tr^-1 = 0.7, where, Prsat = reduced vapor pressure, Tr = reduced temperature. The value of accentric factor is always
a. 2
b. < 1
c. 1
d. < 3
b. < 1
Degress of freedom at triple point will be (E4-129)
a. 0
b. 1
c. 2
d. 3
a. 0
“Law of corresponding states” says that
a. two different gases behave similarly, if their reduced properties (i.e. P, V and T) are same.
b. the surface of separation (i. e. the meniscus) between liquid and vapour phase disappears at the critical temperature.
c. no gas can be liquified above the critical temperature, howsoever high the pressure may be.
d. the molar heat of energy of gas at constant volume should be nearly constant (about 3 calories).
a. two different gases behave similarly, if their reduced properties (i.e. P, V and T) are same.
Linde gas liquefaction process employs cooling
a. by throttling
b. by expansion in an engine
c. at constant pressure
d. none of these
a. by throttling
Pick out the wrong statement pertaining to the decomposition of PCl5 represented by, PCl5 ⇌ PCl3 + Cl2. Degree of dissociation of PCl5 will
a. decrease on addition of Cl2.
b. increase on addition of an inert gas at constant pressure.
c. decrease on increasing the pressure of the system.
d. none of these
d. none of these
Joule-Thomson experiment is
a. isobaric
b. adiabatic
c. isenthalpic
d. both (b) & (c)
d. both (b) & (c)
Boyle’s law for gases states that
a. P ∝ 1/V, when temperature is constant.
b. P ∝ 1/V, when temperature & mass of the gas remain constant.
c. P ∝ V, at constant temperature & mass of the gas.
d. P/V = constant, for any gas.
b. P ∝ 1/V, when temperature & mass of the gas remain constant.
1st law of thermodynamics is nothing but the law of conservation of
a. momentum
b. mass
c. energy
d. none of these
c. energy
In a reversible chemical reaction (where, Δx = number of moles of products-number of moles of reactants )
a. addition of inert gas favours the forward reaction, when Δx is positive.
b. pressure has no effect on equilibrium, when Δn = 0.
c. addition of inert gas has no effect on the equilibrium constant at constant volume for any value of Δx (+ ve, - ve) or zero).
d. all ‘a’, ‘b’ & ‘c’.
d. all ‘a’, ‘b’ & ‘c’.
Out of the following refrigeration cycles, which one has maximum COP ?
a. Air cycle
b. Carnot cycle
c. Ordinary vapor compression cycle
d. Vapor compression with a reversible expansion engine
b. Carnot cycle
Pick out the correct statement:
a. In an isothermal system, irreversible work is more than reversible work.
b. Under reversible conditions, the adiabatic work is less than isothermal work.
c. Heat, work, enthalpy and entropy are all ‘state functions’.
d. Matter and energy can not be exchanged with the surroundings in a closed system.
b. Under reversible conditions, the adiabatic work is less than isothermal work.
In any spontaneous process,
a. only F decreases
b. only A decreases
c. both F and A decreases
d. both F and A increase
c. both F and A decreases
Which of the following is a thermodynamic property of a system ?
a. Concentration
b. Mass
c. Temperature
d. Entropy
d. Entropy
Equilibrium constant decreases as the temperature
a. increases, for an exothermic reaction.
b. decreases, for an exothermic reaction.
c. increases, for an endothermic reaction.
d. none of these.
a. increases, for an exothermic reaction.
The expression, ΔG = nRT ln (P2/P1), gives the free energy change
a. with pressure changes at constant temperature.
b. under reversible isothermal volume change.
c. during heating of an ideal gas.
d. during cooling of an ideal gas.
a. with pressure changes at constant temperature.
All gases during throttling process at atmospheric temperature and pressure show a cooling effect except
a. CO2
b. H2
c. O2
d. N2
b. H2
Compressibility factor for almost all the gases are approximately same at the same
a. pressure and temperature.
b. reduced pressure and reduced temperature.
c. critical pressure and critical temperature.
d. none of these.
b. reduced pressure and reduced temperature.
Pick out the wrong statement.
a. Activity co-efficient is dimensionless.
b. In case of an ideal gas, the fagacity is equal to its pressure.
c. In a mixture of ideal gases, the fugacity of a component is equal to the partial pressure of the component.
d. The fugacity co-efficient is zero for an ideal gas.
d. The fugacity co-efficient is zero for an ideal gas.
The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same.
a. kinematic viscosity
b. work
c. temperature
d. none of these
d. none of these
In jet refrigerators, the refrigerating fluid is practically always
a. water
b. ammonia
c. freon
d. brine
a. water
Water on heating from 1 to 4°C
a. contracts
b. expands
c. has same volume
d. may contract or expand
a. contracts
Pick out the correct statement.
a. Compression ratio of an Otto engine is comparatively higher than a diesel engine.
b. Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio.
c. Otto engine efficiency decreases with the rise in compression ratio, due to decrease in work produced per quantity of heat.
d. Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work.
b. Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio.
When pressure is applied on the system, ice ↔ water, then
a. equilibrium can not be established.
b. more ice will be formed.
c. more water will be formed.
d. evaporation of water will take place.
c. more water will be formed.
Partial molar free energy of an element A in solution is same as its
a. chemical potential
b. activity
c. fugacity
d. activity co-efficient
a. chemical potential
Free energy change at equilibrium is
a. zero
b. positive
c. negative
d. indeterminate
a. zero
Heat pump
a. accomplishes only space heating in winter.
b. accomplishes only space cooling in summer.
c. accomplishes both (a) and (b).
d. works on Carnot cycle.
c. accomplishes both (a) and (b).
The temperature at which both liquid and gas phases are identical, is called the __________ point.
a. critical
b. triple
c. freezing
d. boiling
a. critical
What is the value of ln y (where y = activity co-efficient) for ideal gases ?
a. Zero
b. Unity
c. Infinity
d. Negative
a. Zero
A closed system is cooled reversibly from 100°C to 50°C. If no work is done on the system
a. its internal energy (U) decreases and its entropy (S) increases.
b. U and S both decreases
c. U decreases but S is constant.
d. U is constant but S decreases.
b. U and S both decreases
Which is not a refrigerant ?
a. SO2
b. NH3
c. CCl2F2
d. C2H4Cl2
d. C2H4Cl2
The partial pressure of each constituent present in an alloy is __________ the total vapor pressure exerted by the alloy.
a. less than
b. equal to
c. more than
d. either (b) or (c); depends on the type of alloy
a. less than
Heat is added at constant pressure in an ideal __________ cycle.
a. Stirling
b. Brayton
c. Rankine
d. both (b) and (c)
d. both (b) and (c)
