An investigative experiment is performed with two electrolytic cells connected in series

CHEMISTRY · Multi-part · AP · Chemistry · Thermodynamics and Electrochemistry · Thermodynamics and Electrochemistry

Problem

An investigative experiment is performed with two electrolytic cells connected in series. One cell contains CuSO

_4

(aq) and plates copper metal; the second cell contains an aqueous solution of an unknown metal ion X

^{n+}

. The molar mass of the unknown metal is

91.2\,\text{g}\,\text{mol}^{-1}

. A constant current of

0.965\,\text{A}

is passed for

50.0\,\text{min}

. At the end of the run,

0.600\,\text{g}

of copper and

0.337\,\text{g}

of metal X are collected on their respective cathodes. Using only these data, determine the charge on the ion X

^{n+}

. (a) Calculate the number of moles of copper deposited. (b) Determine the total number of moles of electrons that passed through the circuit during electrolysis. (c) Calculate the number of moles of metal X deposited. (d) Using results from parts (b) and (c), determine the integer value of

n

in X

^{n+}

. (e) Explain how the equality of electric charge in the series circuit supports your calculated value of

n

. Include appropriate reasoning in terms of Faraday’s laws.

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