impurity question

[nickelbackfan]

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I'm under the impression that as something dissociates more (gets more acidic), more impurities are present in solution. This leads to an increase in BP and decrease in freezing point. Can someone clarify why these physical properties are affected by the impurities?

Thanks

 

[Wolverines83]

I'm under the impression that as something dissociates more (gets more acidic), more impurities are present in solution. This leads to an increase in BP and decrease in freezing point. Can someone clarify why these physical properties are affected by the impurities?

Thanks

Think of it this way: Salt water has a higher BP and lower freezing point than normal water. Think of the sodium and chloride as "getting in the way" of water molecules that want to vaporize, thus requiring more energy for them to leave the liquid. Same goes for freezing. Think of the sodium and chloride as getting in the way of the water molecules forming their hydrogen bonding, VDW forces, etc.

Don't go much deeper than that for the MCAT. If you understand that, you should be good.

 

[nickelbackfan]

Thanks!