Calorimeters are isolated systems, partially filled with water, where chemical reactions take place. By measuring the changes in water’s temperature, calorimeters allow calculation of the amount of heat released or absorbed by the reaction.
A student was asked to perform a series of experiments using a coffee-cup calorimeter filled with 200 mL of water. The initial temperature of the calorimeter was 25 °C for each experiment. To calibrate the device, the student added 50 mL of water at 100 °C to the interior of the container, and measured the final temperature of the calorimeter’s interior to be 75 °C. This resulted in a measured heat capacity of 105 J/°C.
Experiment 1. In the first experiment, the student attempted to determine the identity of an unknown piece of metal by measuring its specific heat capacity and comparing against the tabulated values of different substances, as shown in Table 1.
Experiment 2. In the second experiment, the student wanted to calculate the heat of fusion of water. The student added a solid ice cube of mass m and temperature 0 °C into the calorimeter, and measured the final temperature of the system once equilibrium was reached.
|Substance||Specific heat [J/(g°C)]|
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