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4 November, 19:00

A mass of 100.0 g of solute is dissolved in water so that 850. mL of a 0.7500 M solution has been prepared. What is the molar mass of the solute?

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  1. 4 November, 19:24
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    156.86 g / mol

    Explanation:

    We start from the molarity law

    Cm = n / V

    n = w / M

    then

    Cm = (w / M) / V

    Cm = w / (M * V)

    where:

    Cm is the molarity

    n number of moles

    w a mass of the solute

    M is the molar mass of the solute (which is needed)

    V the volume of the solution in liters

    Then the M can be calculated as following:

    M = w / (Cm * V)

    M = 100 / (0.75 * 0.85) = 156.86 g / mol
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