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Q & A: salt water freezing temperature

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Most recent answer: 11/18/2017
Q:
Does salt water's freezing temperature change depending on the type of salt?
- MarBella (age 11)
Nevada
A:

That depends on what you keep the same when you change types of salt. The effect on the freezing temperature depends almost entirely on the number of salt ions per water molecule, until you get to high salt concentrations. At high concentrations details of the individual salts do make a difference. So if you use the same number of moles (a count of the nmber of ions) of two different salts, they'll have the same effect at least at low concentrations. Since each salt has a different weight per mole, if you use the same weight you'll get different effects for diferent salts.

We have some old discussion that might help:https://van.physics.illinois.edu/qa/listing.php?id=1580  https://van.physics.illinois.edu/qa/listing.php?id=18705

Mike W.


(published on 11/18/2017)

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