# Calculating Freezing and Boiling Points

1. Dec 10, 2007

### viper2308

1. The problem statement, all variables and given/known data
Calculate the freezing point and boiling point of each of the following solutions using the observed van't Hoff factors in Table 11.6.

(a) 0.070 m MgCl2
Temp Freezing?

Temp Boiling?

(b) 0.020 m FeCl3
Temp Freezing?

Temp Boiling?

2. Relevant equations
Change in T= imK
i=Van't Hoff factor
m=given
K=freezing point depression or boiling point elevation

3. The attempt at a solution
I don't know what the change in temp is so I can't solve for K.
Tf MgCl2- Change in T= (3)(.07)K Don't know K or T

2. Dec 11, 2007

### Vagrant

∆Tb=New boiling point-Boiling point of pure solvent
∆Tf=Freezing point of pure solvent-New freezing point,
now knowing boiling/freezing point of the pure solvent, i, m and K(which will be given) you can find the new boiling/ freezing point.

3. Dec 11, 2007

### Gokul43201

Staff Emeritus
K is a property of the solvent. It has a specific value for every solvent, and can be looked up in your textbook, or a handbook, or on the web.