Mass NaC1: 3.9984 8 3. 100 mL of water is already in the calorimeter. Use the density of water at 25°C (0.997 g/mL) to determine the mass from the volume and record it below. Make certain the stirrer is On (you should be able to see the shaft rotating). Mass water: 99.7 Mass ice: 0.3 g g Mass Water and Ice = 100 g 4. Click on the Save Data button in the Thermometer section of the Live Data tab in the tray to save data to the lab book. Allow 20-30 seconds to obtain a baseline temperature of the water. Click the clock on the wall labeled Accelerate to accelerate the laboratory time if necessary. Drag the beaker of ice until it snaps into place above the calorimeter and then pour the ice into the calorimeter. Observe the change in temperature in the graph window until it reaches zero. Drag the weigh paper from the balance to the calorimeter and then pour it into the calorimeter. Observe the change in temperature until it reaches a stable minimum and click Stop Saving. Open the Lab Book tab in the tray to view the collected data. Record the lowest temperature after adding the salt below. (Remember that the water may have begun to warm back up.) Minimum temperature = -1.75 °C 5. If you want to repeat the experiment, click on the red disposal bucket or the Clear Lab button to clear the lab, open the Presets menu in the tray and select Lab Preset: Freezing Point Depression - NaCl. . 6. The freezing point depression can be predicted using the equation AT, K₁ mi, where AT is the change in freezing point, i is the number of ions in the solution per mole of dissolved NaC1 (i=2), m is the molality of the solution, and Ky is the molal freezing point constant for water which is 1.86°C/m. Calculate the predicted change in freezing point for your solution. °C 7. The change. freezing point must be subtracted from the freezing point of pure water, which is 0.0 °C, in order to compare the predicted freezing point with the actual freezing point. What is the calculated freezing point of the solution? Compare this to the actual freezing point.