Colligative Properties
When physical properties change when solutes are added to a solvent
Boiling point H O 100 C 1 atm
Freezing
H O 0 C 1 atm
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NaCl : Does adding NaCl to water raise the bp? No
NaCl: Does the freezing point change?
10 %=
g/100 ml
How is the boiling and freezing point of water changed with addition of sucrose?
Surface area, temperature and
mixing all influence rates of dissolving
Sucrose changes both fp and bp of water
Calcium chloride:
Reacts with water is exothermic
Winter: NaCl and CaCl
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NaCl lowers the freezing point to prevent freezing of water forecast prevents freezing at O C; it
will lower it to about -4 C
CaCl will melt the ice, shovel to remove thawed ice before it refreezes
Energy is required to break bonds and energy is released to form bonds
This is not a colligative property it is a chemical property
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