Mass of calorimeter 118.3165 g 118.3208 g 118.3306 g
Mass of calorimeter and hot water 216.8285 g 213.4255 g 217.6734 g
Mass of cup 19.2055 g 19.2041 g 19.2030 g
Mass of cup and total water 186.2238 g 180.4456 g 187.6298 g
Initial Temperature 58.4 °C 56.3 °C 57.3 °C
Final Temperature 0.4 °C 0.2 °C 0.1 °C
1. For each run, calculate the total mass of the water when the experiment is finished, the mass of the initial hot water, and the mass of the melted ice. Which of these masses was for the system for this experiment? Which of these masses was for the surroundings?
2. For each run calculate the qsurr. What is the relationship between qsurr and qsys?
3. For each run calculate Hfus in J/g. Then average your three values.
4. Use your three values for Hfus and the average to calculate your percent deviations.
5. Convert Hfus from J/g to kJ/mole.
6. Look up the accepted value for the enthalpy of fusion of ice (Hfus). Give your source!
Use your average value and the accepted value to calculate your percent error.
7. The equilibrium (final) temperature noted in the procedure is generally above 0.0 °C,
but ice melts and water freezes at 0.0 °C. Why isn’t 0.0 °C a realistic goal for this experiment?
8. List the major sources of error in this experiment.
9. Your teacher may want your class to pool together their results (each group report their final answers for Hfus in kJ/mole) and do some statistical analysis on the entire class’s data. For example, the teacher may have you calculate mean and standard deviations and/or determine if the data you obtained was part of the same “population” of data obtained by the entire lab by doing a “t-test” on the data.