Answer
728 kJ
Work Step by Step
Specific heat of copper metal
$s=0.385\,J/g\cdot \,^{\circ}C$
Mass $m= 6.22\,kg=6220\,g$
Change in temperature
$\Delta T= (324.3-20.5)^{\circ}C=303.8^{\circ}C$
Heat absorbed $q=sm\Delta T$
$=0.385\,J/g\cdot \,^{\circ}C\times6220\,g\times303.8^{\circ}C$
$=728000\,J=728\,kJ$
