Colligative properties

Short Lab report guideline

(therefore, no cover page)

No need to type the lab report. Even a combination of typed and handwritten text can be submitted.

For this report, 4 pages have to be stapled and submitted in the following order (no cover page):

  1. Page 1: Table of data / Results (The page signed by the teacher in the lab and completely filled)
  2. Page 1 (back): Sample Calculation and Answer to the questions (see below)
  3. Pages 2-4: the three graphs in the following order

DO NOT answer the pre-lab and post-lab questions from the lab manual.

Instructions for back of page 1: Sample calculations / Teacher’s questions.

You have to submit 2 sample calculations:

Circle your unknown at the bottom of the data sheet. Pick-up the one with the closest molar mass.

Options for unknowns:

Teacher’s question:

Answer on the back of page 1, the three following multiple choices.

In an experiment you are using the freezing point depression technique to determine a molar mass.
The substance studied has an actual molar mass of 155 g.mol-1 (real value).

What will be the molar mass calculated, or obtained in the lab compared to the real one, if the following error were present in the experiment?

  • a. The student did not wait for all the unknown to completely dissolve before making the measurement.
  • b. The weighed unknown contained an impurity, which was insoluble in the solvent.
  • c. The thermometer consistently displays a temperature 0.5 °C higher than the actual temperature for all experiments.

Possible answers: calculated value: lower than 155 g.mol-1 / no change / higher than 155 g.mol-1

Note: The same answer can be used multiple times, no calculation or explanation is required.

If you choose to submit a joint lab report, please attach both lab data sheets (those of both students) to the beginning of the document