What mass of calcium chloride must be added to 100 grams of water to
make it freeze at 269 K?
please help with detail
Hello! Hope this helps:
The equation you will use is Blagden's Law:
deltaTf=freezing point depression=Tf(water)-Tf(solution)
Kf=cryoscopic constant = 1.853K*kg/mol for water
b=mol CaCl2/kg of water=mol CaCl2/.1kg water
i=number of ion particles per individual molecule of solute(CaCl2) = 3
273-269=(1.853)*(mol CaCl2 / .1)*3
mol CaCl2 = .072 mol
Now use the molar mass of CaCl2, which units are in grams per mole, then multiply by moles to get answer in grams of CaCl2.
CaCl2: 110.98g/mol * .072mol = 8grams (approximately)
Let me know if you have any questions. Please give me a rating so I know how I'm doing. Best of luck to you :).
What calculations gave us .072 mol?
4 / 55.59
ur good thanks!
You're welcome! Give me a good rating if you get the chance :). Good luck with everything else!!!
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