PHY1110L Calorimetry Instructions

The general method for measuring the latent heat of fusion for ice is to measure the initial temperature of the water in the calorimeter cup, ease the ice into the calorimeter cup, and determine how much the temperature of the water decreases. The chief source of systematic error in calorimetric experiments lies in the exchange of heat between the calorimeter and its surroundings by radiation and convection (not truly adiabatic). In this experiment the simplest way to correct for this is to start with the initial temperature of the receiver (can and water) as far above room temperature as the final temperature will be below it. This way the heat lost by the calorimeter to the surroundings during the first half of the experiment (before the ice is added), will be approximately compensated by the heat gained by the calorimeter from the surroundings in the second half of the experiment (after the ice is added). Measure the masses of the calorimeter cup and the stirrer and record these on the Excel worksheet. The cup is aluminum and the stirrer is nickel-plated brass. The specific heat of aluminum is 0.224 cal/(gm  o C) , and of nickel plated brass is 0.090 cal/gm  o C . Trial 1: Fill the calorimeter can 2/3 full of water that is about 5 o C above room temperature and determine the mass of the water. Record the mass of the water onto the Excel worksheet. The specific heat of water is 1.000 cal/(gm·°C) . Assemble the calorimeter with the stirrer and temperature probe. Record the temperature of the water using the temperature probe readout on the computer. While gently agitating the water with the stirrer, allow about 30 seconds to go by to establish a cooling curve showing the loss of heat to the surroundings. Carefully add 1 ice cube and continue taking the temperature and gently agitating the water with the stirrer. The specific heat of ice is 0.500 cal/(gm·°C) . Be sure that the ice is as dry as possible before placing it in the calorimeter. Extra water will have adverse effects to the results. After the final warming trend is clearly established, determine the mass of ice added by subtracting the mass of the system before from the mass of the system after, making this calculation on the Excel worksheet. 2 Temperature Ice Introduced Cooling Curve Room Temperature Equilibrium between water and ice reached Heating Curve Time Figure 2