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Lina20 [59]
3 years ago
12

To determine the freezing point depression of a LiCl solution, Toni adds 0.317 g of LiCl to the sample test tube along with 20.5

mL of distilled water. Determine the concentration, in molality, of the resulting solution. MW of LiCl is 42.394 g/mol Density of H2O is 0.9982 g/mL
Chemistry
1 answer:
Natali [406]3 years ago
4 0

Answer:

0.365 m

Explanation:

The <em>definition of molality</em> is:

  • molality = moles of solute / kg of solvent

First <u>we calculate the moles of the solute, LiCl</u>. We do so using its <em>molar mass</em>:

  • 0.317 g ÷ 42.394 g/mol = 7.48x10⁻³ mol

Then we calculate the mass of the solvent, water. We do so using its <em>density</em>:

  • 20.5 mL * 0.9982 g/mL = 20.5 g
  • 20.5 g / 1000 = 0.0205 kg

Finally we <u>calculate the molality of the solution</u>:

  • 7.48x10⁻³ mol / 0.0205 kg = 0.365 m
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