You have been given a thermometer, styrofoam cup with lid, a beaker, a graduated cylinder, and acces — Calorimetry Chemistry Question

This is a calorimetry problem. The novelty in this question was the intended lack of access to a balance. Students were to make assumptions about the mass of ice based on measured volumes of water prior to adding ice, and the final volume after the ice had been added. Students also had to account for the heat required to increase the temperature of the cold water from the melted ice. Excellent Student Results: Student included initial and final temperatures, determined quantity of ice used, water used, carried out replicate determinations. The coffee cup/lid were constructed as a calorimeter in this experiment.

Conservation of energy applies such that q(ice) + q(cold water) = q(hot water). Once the ice begins to melt (don’t spill, and put the cap on quickly to minimize heat loss) in the calorimetry cup, the hot water becomes colder. Since you don’t end at 0 oC, the equation breaks into: + = . Then solve for Hfus.
Below are sample student data: 10.0 gice Hfus + 10.0 gice-water (4.184) 27.0 – 0.0) = -[ 100ghotwater (4.184) (27.0 – 40.0)
10.0 gice Hfus + 1130 J = 5440 J
10.0 gice Hfus = 4310 J
Hfus = 431 J/g, about a 30% error based on 334 J/g as a correct value.

The question did not specify the units for the reported answer. Acceptable values include: 80.0 cal/g, 6.01 J/mol, 1440 cal/mol, 6.01 kJ/mol, or 1.44 kcal/mol.

Students should provide a cogent discussion of the major sources of error such as heat lost or gained by the system, or inaccuracies of the measuring equipment used.