**About
MOLECULAR WEIGHTS**

* Molecular Weight* or its related value,

How many ways are there to determine a Molecular, Equivalent or Empirical Formula Weight? How many methods have you actually used?

Here is a partial list of methods. You have used almost all of these in this course (General Chemistry Laboratory, Chem 113-114). You should recognize all of them and may even come up with an additional few of the many, many more.

- Colligative Properties
**Freezing point depression**- also Boiling point elevation and Osmotic pressure (not studied)

- Elemental Analysis
- Determine the empirical formula
and calculate empirical formula weight from
Atomic Weights in
**Hydrates**

- Determine the empirical formula
and calculate empirical formula weight from
Atomic Weights in
- Gas Laws
**Dumas method,**measuring the density of a gas- Measuring
**volume of gas generated**in a reaction - also Gaseous Diffusion (not studied)

- Solution Stoichiometry
- Weight of acid and volume and molarity of base needed to neutralize it in pH and BUFFERS as well as the LAB PRACTICAL
- Amount of
**reagent used to react**with a given mass of reactant

- Calorimetry
- Rule of
**Dulong and Petit**... Molar heat capacity is approximately 25 j/mol/° C for Avogadro's number of particles

- Rule of

**© **RWK