Anonymous
Anonymous asked in Science & MathematicsChemistry · 7 years ago

Calculate the time required to reduce the concentration of Ag+?

Calculate the time required to reduce the concentration of Ag+ to 0.5 M, starting from 500 ml of a 5M solution AgNO3 with a current of 10 A

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  • Dr W
    Lv 7
    7 years ago
    Favorite Answer

    moles Ag initial...

    500mL x (1L / 1000mL) x (5 mol AgNO3 / L) x (1 mol Ag+ / 1 mol AgNO3) = 2.5 mol Ag+

    moles Ag final..

    500mL x (1L / 1000mL) x (0.5 mol AgNO3 / L) x (1 mol Ag+ / 1 mol AgNO3) = 0.25 mol Ag+

    mole Ag plated out = 2.5 mol - 0.25 mol = 2.25 mol Ag+

    *****

    and from this reaction

    1 Ag+ + 1 e- ---> 1 Ag(s)

    and from these conversion factors

    1 amp = 1 C / sec

    1 e- = 1.602x10^-19C

    we can easily convert..

    2.25 mol Ag x (1 mol e- / 1 mol Ag) x (6.022x10^23 e- / mole e-) x (1.602x10^-19C / e-) x (1 sec / 10C) = 2.17x10^4 secs

    which works out to be 6 hours, 1 min, and 46 seconds.

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