The direction of the transfer of heat energy is dependent on the initial temperature of the metal and the water. Since the initial temperature of the metal is higher than the initial temperature of the metal, heat energy will be transferred from the metal to the water. Let’s use the following equation to determine the amount of heat energy that is transferred.
Q = mass * specific heat * ∆ T
For the iron, ∆ T = 100 – 17.6 = 82.4˚
For the water, ∆ T = 17.6 – 16 = 1.6˚
For the iron, Q = m * 0.460 * 82.4 = m * 37.904
For the water, Q = 140 * 4.186 * 1.6 = 937.664 J
m * 37.904 = 937.664
m = 937.664 ÷ 37.904
The mass of the metal is approximately 24.7 grams.