Calculating Freezing and Boiling Points

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SUMMARY

This discussion focuses on calculating the freezing and boiling points of solutions using the van't Hoff factor and the formula ΔT = imK. For the 0.070 m MgCl2 solution, the van't Hoff factor (i) is 3, while for the 0.020 m FeCl3 solution, it is 4. The change in temperature (ΔT) can be determined once the specific K values for the solvents are obtained from reliable sources such as textbooks or online databases. The calculations require knowledge of the freezing point depression and boiling point elevation equations.

PREREQUISITES
  • Understanding of colligative properties in chemistry
  • Familiarity with the van't Hoff factor
  • Knowledge of freezing point depression and boiling point elevation equations
  • Ability to access and interpret solvent property tables
NEXT STEPS
  • Research the specific K values for common solvents used in freezing point and boiling point calculations
  • Learn how to accurately apply the van't Hoff factor in various solution scenarios
  • Explore examples of freezing point depression and boiling point elevation calculations
  • Investigate the impact of ionic vs. molecular solutes on colligative properties
USEFUL FOR

Chemistry students, educators, and professionals involved in solution chemistry, particularly those focused on colligative properties and thermodynamic calculations.

viper2308
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Homework Statement


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?



Homework Equations


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


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
 
Physics news on Phys.org
∆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.
 
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.

See the tables on this page: http://dbhs.wvusd.k12.ca.us/webdocs/Solutions/BP-Elev-and-FP-Lower.html
 
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