Answer:
m = 476.5[g].
Explanation:
In order to solve this problem, we must use the following equation of thermal energy.

where:
Q = heat energy = 1576 [cal]
Cp = specific heat = 0.39 [cal/g*°C]
T_final = final temperature [°C]
T_initial = initial temperature [°C]
m = mass of the piece of zinc [g]
We must keep in mind that the difference of the final temperature minus the initial temperature results in the increase in temperature.
![T_{final}-T_{initial} = 8.7[C]](https://tex.z-dn.net/?f=T_%7Bfinal%7D-T_%7Binitial%7D%20%3D%208.7%5BC%5D)
Now replacing:
![1576=m*0.39*(8.7)\\m=476.5[g]](https://tex.z-dn.net/?f=1576%3Dm%2A0.39%2A%288.7%29%5C%5Cm%3D476.5%5Bg%5D)