1.  Safety
2.
Objectives/Overview
3.
Procedures
4.
Observations
5.

Equipment

6.

View Techniques

7.

Waste Disposal/Clean-up

8. Conclusions
9. Calculations/Set-Ups
10. Grading Scale 
11. Review Prelab Questions
12.
Review Postlab Questions

Experiment 14
Using Freezing Point Depression to Find Molecular Weight

PRE-LABORATORY QUESTIONS

References: Brown, Lemay, and Bursten, Chemistry the Central Science, 8th ed. (2000)
pp. 486-489 (colligative properties)
pp. 490-491 (freezing point depression)

Learning Center: answers to pre- and post-lab questions.

SHOW SET-UP FOR ALL CALCULATION PROBLEMS

Calculate the molecular mass of an unknown compound given the following data from a freezing point depression experiment:

0.845 g of the unknown dissolved in 4.250 g of camphor had a freezing point of 1.36°C. The freezing-point depression constant for camphor is 40.°C.kg/mol and the melting point of pure camphor is 129°C.

1. Calculate the freezing temperature depression, ŠT

2. Calculate the molality

3. Calculate the number of moles present of the unknown compound

4. Calculate the experimental molar mass of the unknown compound



 
 
 
 
 

 

Index Proceedures Charts & Tables Safety Experiments Policies Equipment Main Safety Index Procedures Charts and Tables Safety Experiments Policies Equipment Main