A chemist is studying an aqueous nitrate solution of an unknown metal

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

Problem

A chemist is studying an aqueous nitrate solution of an unknown metal, denoted E. The solution has the formula

E(\mathrm{NO}_3)_x\,(aq)

, where

x

is an integer greater than 1. A clean inert electrode is placed in the solution, and a constant current of

2.50\,\text{A}

is applied for

15.0\,\text{min}

. At the end of the run,

0.589\,\text{g}

of pure metal E has plated out onto the electrode. The molar mass of element E is

45.0\,\text{g/mol}

. Assume standard laboratory temperature and pressure throughout the experiment. (a) Calculate the total electrical charge that flowed through the circuit during the electrolysis. (b) Determine the number of moles of metal E deposited. (c) Using your results from parts (a) and (b), determine the value of

x

in the formula

E(\mathrm{NO}_3)_x

. Show your reasoning clearly. (d) Write the balanced half-reaction for the reduction of the cation of element E at the cathode, including states of matter.

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