1. What happened to the shape of the cooling curve when the solutions froze? Why would you expect that?

2. What was the purpose of finding the freezing point of distilled water? Is it consistent with what you would expect?

3. What would you expect the vant Hoff factor for hydrochloric acid to be? Explain why.

4. Calculate the expected freezing point of your hydrochloric acid solution. Compare it to your average experimental freezing point; include a percent error.

5. Using your data, calculate the experimental value of the vant Hoff factor for acetic acid. What does this value tell you about the strength of acetic acid as an electrolyte?

6. Consider your cooling curve collected in Part III with pure distilled water. Draw a copy below (roughly to scale) and mark the region in which supercooling occurs. Draw an arrow to mark the point at which you added the seed crystal. Label the regions of the curve with the phase(s) present.

7. What happened to the temperature of the surrounding supercooled liquid water when freezing began? Does this suggest that the process of freezing is endothermic or exothermic?