Thermodynamics and Thermochemistry 1 Question 31

34. One mole of a non-ideal gas undergoes a change of state $(2.0 \mathrm{~atm}, 3.0 \mathrm{~L}, 95 \mathrm{~K}) \longrightarrow(4.0 \mathrm{~atm}, 5.0 \mathrm{~L}, 245 \mathrm{~K})$ with a change in internal energy, $\Delta E=30.0 \mathrm{~L}$-atm. The change in enthalpy $(\Delta H)$ of the process in L-atm is

(2002, 3M)

(a) 40.0

(b) 42.0

(c) 44.0

(d) not defined, because pressure is not constant

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Solution:

  1. $\Delta H=\Delta U+\Delta(p V)=30+2(5-3)+5(4-2)=44 \mathrm{~L} \mathrm{~atm}$.