Answer
$-136.3\ kJ/mol$
Work Step by Step
From the definition of heat capacity:
$(650\ g\times 4.184\ J/g.K+550\ J/K)\times(22.3-18.5)\ K=12.4\ kJ$
With a negative sign since the temperature raises.
Number of moles of ethanol:
$4.20\ g\div 46.07\ g/mol=0.091\ mol$
Hence:
$-12.4\ kJ\div 0.096\ mol=-136.3\ kJ/mol$
