Answer
$-2812 \ kJ/mol$
Work Step by Step
From the definition of heat capacity:
$(575\ g\times 4.184\ J/g.K+650\ J/g)\times (25.23-21.70)\ K=10.8\ kJ$
Since it's an exothermic process, the sign is negative.
Number of moles of glucose:
$0.692\ g\div 180.16\ g/mol=0.00384\ mol$
Hence:
$\Delta U=-10.8\ kJ/0.00384\ mol=-2812 \ kJ/mol$
