Answer
The energy lost during this process is equal to 904 calories or 3780 joules.
Work Step by Step
$$\Delta T = T_2 - T_1 = (-42.0 ^oC) - (60.5^o C) = -102.5^o C$$
Calories:
$$Heat = m \times \Delta T \times SH$$ $$Heat = (15.0 \space g)(-102.5 ^oC)(0.588 \space cal/g \space ^o C) = -904 \space cal$$
Joules:
$$Heat = m \times \Delta T \times SH$$ $$Heat = (15.0 \space g)(-102.5 ^oC)(2.46 \space J/g \space ^o C) = -3782 \space J$$
3 significant figures: $-3780 \space J$
