Molar Mass Of Unknown # 43 Using The Derived Freezing Point Depression

Purpose:
The purpose of this experiment was to determine the molar mass of unknown #43 using the derived freezing point depression. To obtain the freezing point depression, t-butyl alcohol was placed in a cold-water bath and frozen solid for a total of two runs. Then, unknown #43 was dissolved in t-butyl alcohol and placed in a cold-water bath until frozen solid. This process was repeated for a total of three runs, with the first two runs containing half of the unknown, and the last run containing the full amount of unknown. Using the equation m = ΔTf/Kf , the molality of the unknown solution was found. Then, moles of unknown were calculated, which was used to calculate the average molar mass of unknown.
Theory:
After the experiment was completed, the data

Using the data from the first two columns, an x-y scatterplot graph was created. Analyzing the graph, a set of points that formed a linear curve were identified, and the plot of the graph was reduced to these points. This is the initial cooling curve. A second series was then added to the graph, with points that correspond to the interval when t-butyl alcohol was freezing. A trendline was then created for each of the series to obtain the equation of the line and r values. The equations for both trendlines were then set equal to each other to obtain the x value, which was then inputted back into one of the trendline equations to obtain the freezing point (y value). This process was repeated for each of the unknown

Modifications of this procedure include the use of hot plates instead of Bunsen burners, and heating t-butyl alcohol to 60-65 ℃ instead of 50 ℃. Other modifications include the use of weighing boats to measure an amount of unknown instead of weighing paper, and completing one run of unknown 2 instead of two runs of unknown 2.
Summary of