Answer
480.3 kJ
Work Step by Step
Given that
$\hspace{2cm}\Delta H= +483.6\,kJ/mol$
$\hspace{2cm}P= 1.00\,atm$
$\hspace{2cm}\Delta V= 32.7\,L$
Recall that $\Delta U= \Delta H-P\Delta V$
$=483.6\,kJ-1.00\,atm\times32.7\,L$
$=483.6\,kJ-32.7\times0.1013\,kJ$
(As $1\,L\cdot atm=101.3\,J=0.1013\,kJ$)
$=483.6\,kJ-3.31\,kJ=480.3\,kJ$
