1. As a research chimst, you are intrested in studying the extent and type of interactions in aqueous salt solution. As part of this study, you weight three samples of NaCl and dissolve each in 1.000kg H2O. You then measure the freezing temp. of each solution and compare these temp. to the freezing point of water. The data you collected are tabulated below. Explain the observed results.

Predict and brifly explain the results you would expect for a solution made up of 29.22 g NaCl dissolved in 1.000kg H2O.

g NaCl per 1.000kg H2O ÄTf . °C



5.845 0.348



0.585 0.0360



0.293

0.0182

2. A student determines the Kf of t-butyl alcohol using tap water instead of distilled or deionized water. Described the problem that might have been encounted. How would problems affect the magnitude of Kf?

1 answer

If you have tabulated the data it isn't clear what you've posted.

For the second problem,
delta T alcohol = i*Kf*m
Kf = delta T/i*m
If you used tap water, which contains minerals, then i will be greater than 1 and Kf will be smaller than expected.