1. Calculate the mass of solute that must be dissolved in 50.00 mL of deionized

Question

1. Calculate the mass of solute that must be dissolved in 50.00 mL of deionized water to prepare each of the solutions listed on p. 18 (0.5 m methanol, 0.5 m NaCl, 0.5 m CaCl2). Assume that the density of deionized water is 1 gmL. Show your work and label the units. 2. For each of the solutions listed on p. 18 that will be analyzed in this experiment (0.5 m methanol, 0.5 m Naci, 0.5 m CaCl2), a) list the van't Hoff factor (i) b) calculate the theoretical freezing point depression (ATf of the solution. Show your work and label the units. 3. Explain, in your own words, the difference between freezing point (Tf and freezing point depression (AT

Explanation / Answer

1. molality = moles of solute/kg of solvent

For 0.5 m NaCl

molar mass of NaCl = 58.44 g/mol

solvent water = 50 ml

mass of water = densit x volume = 50 x 1 = 50 g = 0.050 kg

So, mass of NaCl required = 0.5 x 0.05 x 58.44 = 1.461 g

For 0.5 m CaCl2

molar mass of CaCl2 = 110.98 g/mol

solvent water = 50 ml

mass of water = densit x volume = 50 x 1 = 50 g = 0.050 kg

So, mass of CaCl2 required = 0.5 x 0.05 x 110.98 = 2.774 g

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