Exam (elaborations)
Chemical Engineering Thermodynamics Guide Questions and Answers 2024
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Chemical Engineering Thermodynamics Guide
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Chemical Engineering ThermodynamicsGuide
Isothermal - answer Maximum work that could be secured by expanding the gas over a
given pressure range is the __________ work.
-isothermal
-adiabatic
-isentropic
-none of these
zero
(Internal energy is a state function, cycling back to the initial state means no change) -
answerInternal energy change of a system over one complete cycle in a cyclic process
is
-zero
-+ve
- -ve
-dependent on the path
Isobaric
(atmospheric pressure is always constant) - answerHeating of water under atmospheric
pressure is an __________ process.
isochoric
isobaric
adiabatic
isothermal
Binary Solutions - answerVan Laar equation deals with the activity co-efficients in
binary solutions
ternary solutions
azeotropic mixture only
none of these
Viscosity - answerHigh __________ is an undesirable property for a good refrigerant.
,specific heat
latent heat of vaporisation
viscosity
specific vapor volume
Low pressure/Low temperature
( reduce pressure = increase in volume)
(low temp = Increase heat loss from the system) - answerSolubility of a substance
which dissolves with an increase in volume and liberation of heat will be favoured by the
-low pressure and high temperature.
-low pressure and low temperature.
-high pressure and low temperature.
-high pressure and high temperature.
disorder - answerEntropy is a measure of the __________ of a system.
disorder
orderly behaviour
temperature changes only
none of these
negative - answerA chemical reaction will occur spontaneously at constant pressure
and temperature, if the free energy is
zero
positive
negative
none of these
second
(Taken from Classius Statement: "Heat cannot flow from cold to hot without external
work") - answer.
Fundamental principle of refrigeration is based on the __________ law of
thermodynamics.
zeroth
first
second
third
decreases whereas the entropy increases - answerFor a spontaneous process, free
energy
,-is zero
-increases
-decreases whereas the entropy increases
-and entropy both decrease
Carnot refrigeration cycle.
(Max efficiency is always Carnot) - answerA 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 ?
-Vapor compression cycle using expansion valve.
-Air refrigeration cycle.
-Vapor compression cycle using expansion engine.
-Carnot refrigeration cycle.
>1
(COP is the inverse of heat engine efficiency, and heat engine efficiency is always less
than 1 so COP is always greater than 1) - answerIn a working refrigerator, the value of
COP is always
0
<0
<1
>1
both (a) and (b) - answer__________ increases with increase in pressure.
-The melting point of wax
-The boiling point of a liquid
-both (a) and (b)
-neither (a) nor (b
heat pump
(Heat is "pumped" from a cold body to a hot body) - answerA refrigerator may be
termed as a
heat pump
heat engine
Carnot engine
none of these
increases
, (Lewis-Randall rule: fugacity of component in an ideal solution is directly proportional to
the mole fraction of the component in the solution. ) - answerFor a stable phase at
constant pressure and temperature, the fugacity of each component in a binary system
__________ as its mole
fraction increases.
-decreases
-increases
-remains same
-decreases linearly
Heat capacity
(The values of heat capacity are different in mass and molar values so it is influenced
by the amount of substance) - answerWhich of the following is not an intensive
property ?
-Chemical potential
-Surface tension
-Heat capacity
-None of these
Air Cycle
(Air has less specific heat value and it requires more space for heat transfer) -
answerOut of the following refrigration cycles, which one has the minimum COP (Co-
efficient of performance)?
-Air cycle
-Carnot cycle
-Ordinary vapour compression cycle
-Vapour compression with a reversible expansion engine
zeroth - answerMeasurement of thermodynamic property of temperature is facilitated by
__________ law of thermodynamics.
1st
zeroth
3rd
none of these
-RT ln 0.5 - answerThe 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
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