Question

A student is preparing to perform a series of calorimetry experiments. She first wishes to determine the calorimeter constant (ccal) for her coffee cup calorimeter. She pours a 50.0 ml sample of water at 345 K into the calorimeter containing a 50.0 ml sample of water at 298 K. She carefully records the final temperature of the water as 317 K. What is the value of ccal for the calorimeter? The specific heat capacity of water = 4.18 J/g°C.

Answer 1

The calorimeter constant (ccal) is determined by calculating the heat transfer between two water samples in a coffee cup calorimeter. The heat lost by the hot water equals the heat gained by the cold water plus the heat absorbed by the calorimeter. This allows for the calculation of ccal using the specific heat capacity of water and the mass and temperature change of the samples.

Step-by-step explanation:

The student aims to find the calorimeter constant (ccal) for a coffee cup calorimeter. This is determined by equalizing the temperature of two samples of water at different initial temperatures in the calorimeter and measuring the final equilibrium temperature. Using the principle of conservation of energy, we know that the heat lost by the hot water will be equal to the sum of the heat gained by the cold water and any heat absorbed by the calorimeter.

The steps to calculate ccal are as follows:

1. Calculate the mass of each water sample using the density of water (1 g/ml) and volume.
2. Calculate the heat lost by the hot water and the heat gained by the cold water, using the specific heat capacity of water (4.18 J/g°C), the mass, and the change in temperature.
3. Since the total heat lost must equal the total heat gained, the difference between the heat lost by the hot water and heat gained by the cold water will be absorbed by the calorimeter, which is ccal times the temperature change.

Using these steps, the student can solve for ccal.