A student dissolves 7.9 g of stilbene (C14H12) in 475. mL of a solvent with a density of 1.03 g/mL. The student notices that the volume of t

Question

A student dissolves 7.9 g of stilbene (C14H12) in 475. mL of a solvent with a density of 1.03 g/mL. The student notices that the volume of the solvent does not change when the stilbene dissolves in it. Calculate the molarity and morality of the students solution. Round both of your answers to 2 significant digits.

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Phúc Điền 5 years 2021-07-14T19:35:00+00:00 1 Answers 32 views 0

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  1. RuslanHeatt
    0
    2021-07-14T19:36:23+00:00
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    Answer:

    Molarity: 0.092M

    Molality: 0.090m

    Explanation:

    Molarity, M, is defined as the moles of solute (In this case, C14H12 -Molar mass: 180.25g/mol-) in 1L of solution.

    The molality, m, are moles of solute per kg of solvent.

    Molarity:

    Moles solute:

    7.9g * (1mol/180.25g) = 0.04383 moles

    Liters solution:

    475mL = 0.475L

    Molarity: 0.04383 moles / 0.475L = 0.092M

    Molality:

    kg solvent:

    475mL * (1.03g/mL) = 489.25g = 0.48925kg

    Molality:

    0.04383 moles / 0.48925kg = 0.090m

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