Chemistry Practice Problems Freezing Point Depression Practice Problems Solution: You need to make a solution that freezes at -125.0...

Solution: You need to make a solution that freezes at -125.0 °C. How many grams of CaCl2 salt must you add to 68.0 g of ethanol (C2H6O) to make a solution that freezes at -125.0 °C? Reminder: Pure ethanol freezes a -114.1 °C. For ethanol: KF = 1.99 °C/m KB = 1.22 °C/m Molar masses: Ethanol = 46.07 g/mol; CaCl2 = 110.98 g/mol

Problem

You need to make a solution that freezes at -125.0 °C. How many grams of CaCl2 salt must you add to 68.0 g of ethanol (C2H6O) to make a solution that freezes at -125.0 °C? 

Reminder: Pure ethanol freezes a -114.1 °C. For ethanol: KF = 1.99 °C/m KB = 1.22 °C/m 

Molar masses: Ethanol = 46.07 g/mol; CaCl2 = 110.98 g/mol

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