Answer to Question #222148 in General Chemistry for Sajeel Ahmed

Question

calculate the internal energy of enthalpy of any random system.also find out the mathematical relation between internal energy enthalpy and then entropy?

Answer 1

$U=\frac{m}{M}C_VT$

For air $M=28.96 \cdot 10^{-3}kg/mol$ and $C_V=\frac{i}{2}R=\frac{5}{2}\cdot 8.31\approx20.8\frac {J}{mol\cdot K}$

$U=\frac{m}{M}C_VT=\frac{1}{28.96 \cdot 10^{-3}}\cdot 20.8\cdot 293=210442J$

The enthalpy of air

$H=U+pV=210442+2\cdot 10^6\cdot 0.05=310442J$

Enthalpy is the sum total of all the energies, whereas entropy is the measure of the change in enthalpy/temperature.