What are the normal freezing points and boiling points of the following solution

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a) Molar mass NaCl = 58.442 g/mol Moles NaCl = 19.2 / 58.442 = 0.328 NaCl is an electrolyte >> Na+ + Cl- delta T = kf x m x i kf = 1.86 m is the molality ( in our case we have molarity but we can assume m = M) i is the number of ions produced ( in our case i =2) V = 193 mL = 0.193 L M = 0.328 / 0.193 = 1.699 delta T = 1.86 x 1.699 x 2 = 6.32 °C The f.p will be - 6.32°C About the elevation of boiling point delta T = kb x m x i kb = 0.512 delta T = 0.512 x 1.699 x 2 = 1.74 The b.p. will be 101.74 °C b)Molar mass urea = 60 g/mol Moles urea = 14.6 / 60 = 0.243 Concentration = 0.243 / 0.0671 L = 3.62 M Urea is a non-electrolyte so i = 1 delta T = 1.86 x 3.62 = 6.73 The f.p. will be - 6.73 °V delta T = 0.512 x 3.62 = 1.85 The b.p. will be 101.85 °C

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