Quote:
Originally Posted by JohnnyD
I hate to nitpick, but isn't dissolving a physical change? You mix table salt into water, then evaporate all the water and you'll still have table salt. If it were a chemical reaction, then a new compound would have to be created.
Dissolving salts into water raises the boiling point of water and lowers the freezing point. I believe calcium chloride lowers the freezing point more than NaCl would and is why it is more effective at dealing with ice.
I always loved chemistry in college is high school.
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No quite correct, JD.
Is mixing calcium chloride and water a chemical reaction?
Answer YES
CaCl2(aq) + H2O(aq) = 2HCl(aq) + CaO(s)
You con't get CaCl2 back.
More importantly for melting snow: the reaction is exothermic giving off HEAT.
(thermometer is in Celsius)