Show that Cp is greater than Cv .
Answers
⭕️At constant pressure (Cp), part of heat supplied is used by the system in doing work.
⭕️ more heat is needed to increase the temperature by a given amount.
✔️✔️for derivation :-
✔️✔️by using the 'First law of thermodynamics'
@ constant Pressure
dQ=dU+P.dV ➖➖➖(1)
At Constant Volume,
dQ=dU+P.dV
Since dV=0
Therefore dQ=dv ➖➖➖(2).
Cp=dU+P.dV
And Cv=dU
from above we can say that relation Cp is greater than Cv.
What is Cp and Cv ?
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☑Cp is the specific heat at constant pressure .
☑Cv is the specific heat at constant volume
Now ,
What is specific heat ?
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☑Amount of heat that required to raise the temperature by 1°C .
Why Cp is always greater than Cv?
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As Cp is amount of heat that required to raise the temperature by 1°C when heat is given at constant pressure.
So pressure is fixed in Cp but some work may be done . So heat may produce.So more energy required to increase the temperature of system.
But ,
Cv is the amount of heat that required to raise the temperature by 1°C when heat is given at constant volume.
According to the equation
W = P∆V
if volume is constant then workdone is Zero . So no heat produced .Whole energy is used to increase the temperature of a system.
Result
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So we get that Cp > Cv