PROCEDURE PART 2: EFFECT OF NUMBER OF PARTICLES ON FREEZING POINT DEPRESSION (Cal2 in water)
1. Change the chemical to calcium chloride, and reset the number of moles to 1. (see example to the right) Press the "play" button and watch the simulation until the temperature reading (upper right corner) remains constant or until the simulation stops. Record this temperature in the data table below.
2. Repeat step 1 two more times, changing the amount of solute to 2
DATA TABLE PART 2: CaCl, in Water
Moles of CaCl used
1.0
2.0
3.0
Freezing point of solution, °C
PROCEDURE PART 2: EFFECT OF NUMBER OF PARTICLES ON FREEZING POINT DEPRESSION (Cal2 in water)
1. Change the chemical to calcium chloride, and reset the number of moles to 1. (see example to the right) Press the "play" button and watch the simulation until the temperature reading (upper right corner) remains constant or until the simulation stops. Record this temperature in the data table below.
2. Repeat step 1 two more times, changing the amount of solute to 2
DATA TABLE PART 2: CaCl, in Water
Moles of CaCl used
1.0
2.0
3.0
Freezing point of solution, °C
2. What do you notice about the freezing points of the calcium chloride solutions as compared to the sodium chloride solutions?
3 On the same graph that you made in Question #3 in part 1 above, graph the data for the calcium chloride solution using a different color.
4. Write a statement summarizing the relationship between number of particles that a solute will dissociate into and the freezing point of the solution.
5. PREDICT: How do you think the freezing point of a 1.0 m AlCI solution would compare to a 1.0 m NaCl or CaCla solution?
2. The freezing points of the calcium chloride solutions are lower than the sodium chloride solutions, indicating a greater depression of the freezing point due to the presence of more particles in the calcium chloride solution.
4. The relationship between the number of particles that a solute will dissociate into and the freezing point of the solution is that the more particles the solute dissociates into, the greater the depression of the freezing point.
5. The freezing point of a 1.0 m AlCl3 solution would be lower than a 1.0 m NaCl or CaCl2 solution because aluminum chloride will dissociate into more particles, resulting in a greater depression of the freezing point.