Answer:
About 28.9 kJ.
Explanation:
Recall the formula for specific heat:
[tex]\displaystyle q = mC\Delta T[/tex]
Where q is the amount of heat released, m is the mass of the substance, C is its specific heat, and ΔT is the change in temperature.
Therefore, by substitution, we have that:
[tex]\displaystyle \begin{aligned} q & = (625\text{ g})\left(\frac{0.900 \text{ J}}{\text{g-$^\circ$C}}\right)\left(\frac{1 \text{ kJ}}{1000 \text{ J}}\right) \left(82.1^\circ\text{C}-30.7^\circ \text{C}\right) \\ \\ & = (625\text{ g})\left(\frac{0.900 \text{ J}}{\text{g-$^\circ$C}}\right)\left(\frac{1 \text{ kJ}}{1000 \text{ J}}\right)(51.4^\circ\text{C}) \\ \\ & = 28.9\text{ kJ}\end{aligned}[/tex]
In conclusion, about 28.9 kJ of energy is needed.
