Answer
$\Delta S = 3.78 \times 10^3 J/K$
Work Step by Step
$Q_H = (0.0286 gal) × (1.23 ×10^8 J/gal) $
$Q_H = 3.52 ×10^6 J$
$Q_C = 3/4 \times Q_H$
$Q_C = 3/4 \times 3.52 ×10^6 J$
$Q_C = 2.64 \times 10^6 J$
$\Delta S = \frac{Q_H}{T_H} + \frac{Q_C}{T_C} $
$\Delta S = \frac{-3.52 ×10^6 J}{673 K} + \frac{2.64 \times 10^6 J}{293K} $
$\Delta S = 3.78 \times 10^3 J/K$