Calculate Qsp for calcium fluoride when 100.0 mL of a 6.05×10-3 M  solution of Ca(NO3)2 is added to 270.0 mL of a 5.75×10-3 M solution of KF?

Calculate Qsp for calcium fluoride (Ksp = 3.9 ×10–11) when 100.0 mL of a 6.05×10-3 M  solution of Ca(NO3)2 is added to 270.0 mL of a 5.75×10-3 M solution of KF.

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  • Fern
    Lv 7
    3 weeks ago

    Moles of Ca(NO3)2 = 6.05 x 10^-3 moles Ca(NO3)2/ liter x 0.1000 liters = 6.05 x 10^-4 moles Ca(NO3)2

    Moles of Ca2+ = 6.05 x 10^-4 moles

    Moles of KF = 5.75 x 10^-3 moles KF/liter x 0.270 liters = 1.55 x 10^-3 moles KF ; moles of F- = 1.55 x 10^-3 moles

    Final volume = 0.100 liters + 0.270 liters = 0.370 liters

    [Ca2+] = 6.05 x 10^-4 moles/0.370 liters = 1.635 x 10^-3

    [F-] = 1.55 x 10^-3 moles/0.370 liters = 4.19 x 10^-3

    CaF2(s) ⇐=> Ca2+ + 2F-

    Ksp = [Ca2+][F-]^2

    Qsp = 1.635 x 10^-3(4.19 x 10^-3)^2 = 2.87 x 10^-8

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