Chemical Engineering Thermodynamics - Study Mode
[#181] C v is given by
Correct Answer
(A) $${left( {frac{{partial { ext{E}}}}{{partial { ext{T}}}}}
ight)_{ ext{V}}}$$
Explanation
Solution: Definition of $${C_V}$$ : when we add the heat to a system which is undergoing only expansion work or $$PdV$$ work at constant volume than the amount of heat required to raise the temperature by an infinitesimal amount is called as $${C_V}$$. $${C_V} = mathop {lim }limits_{delta T o ,0} frac{{partial Q}}{{partial T}}$$ By first law of thermodynamics: $$delta Q = dU + delta Wleft( {PdV}
ight)$$ xa0 xa0 Since here $$dV=0$$ $$delta Q = dU$$ So, $${C_V} = {left( {frac{{dU}}{{dT}}}
ight)_V}.$$ xa0 Where $$U=$$ xa0internal energy.
[#182] Kopp's rule is used to calculate the heat capacity of
Correct Answer
(A) Solids
Explanation
Solution: Kopp's rule states that the heat capacities of a molecular compound are sum of the contributions for each element in the compound. And it generally used to find the heat capacities of solids or liquid at $${20^{ ext{o}}}C$$ xa0 for example the heat capacity of calcium chloride $$left( {CaC{l_2}}
ight)$$ xa0 can be written as heat capacity of $$Ca + {2,,*}$$ xa0 heat capacity of $$Cl$$ .
[#183] The temperature at which a real gas obeys the ideal gas laws over a wide range of pressure is called __________ temperature.
Correct Answer
(A) Boyle
Explanation
Solution: The temperature at which a real gas obeys the ideal gas laws over a wide range of pressure is called as Boyle temperature.
[#184] A system in which there is exchange of energy but not of mass, is called a/an __________ system.
Correct Answer
(D) Closed
Explanation
Solution: A system which exchanges the energy but not mass is called as closed system or control mass system where the identity of mass also should remain same.
[#185] The activity of an ideal gas is numerically __________ its pressure.
Correct Answer
(C) Equal to
Explanation
Solution: Activity $$left( a
ight)$$ of a pure ideal gas is defined as: $$a = frac{{{ ext{fugacity at an temperature and pressure of interest}}}}{{{ ext{fugacity at same temperature and standard pressure }}}}$$ usually the, standard pressure $$=$$ 1 atm and for ideal gas fugacity at a temperature and pressure $$=$$ pressure at that conditions So, $$a=P$$