A rock salt (NaCl), ice, and water mixture is used to cool milk and cream to make homemade ice cream. How many grams of rock salt must be added to water to lower the freezing point 16.5°C?

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anonymous · Answer

can anybody help me?

anonymous · Answer

the freezing point depression is 1.86 °C for a 1 molal solution. For a 12.7° depression, the solution must be 12.7/1.86 = 6.83 molal in particles. 
Rock salt (= NaCl) dissociates into Na+ and Cl-, which both count as particles, so the solution must be
3.42 molal. 
Which is 58.44*3.42 g/ kg water = 199.6 g NaCCl /kg water.

anonymous · Answer

thank you soooooo much!..youre a life saver!

anonymous · Answer

Calculate the freezing point and boiling point of a solution that contains 51.1 g NaCl and 45.9 g KBr dissolved in 750.3 mL H2O.

anonymous · Answer

Yep no problem