Copper can be electroplated at the cathode of an electrolysis cell by the half-reaction: Cu2+(aq) + 2 e- → Cu(s). How much time would it take for 325 mg of copper to be plated at a current of 5.6 A?

Verified step by step guidance

1. Convert the mass of copper from milligrams to grams by dividing by 1000.
2. Calculate the number of moles of copper using its molar mass (63.55 g/mol).
3. Use the stoichiometry of the half-reaction to determine the moles of electrons required. Since 1 mole of Cu requires 2 moles of electrons, multiply the moles of Cu by 2.
4. Apply Faraday's Law of Electrolysis: Q = n * F, where Q is the total charge in coulombs, n is the moles of electrons, and F is Faraday's constant (96485 C/mol).
5. Calculate the time using the formula t = Q / I, where t is time in seconds, Q is the total charge, and I is the current (5.6 A).

Key Concepts

Electrolysis

Electrolysis is a chemical process that uses electrical energy to drive a non-spontaneous reaction. In this context, it involves the reduction of copper ions (Cu2+) at the cathode, where they gain electrons to form solid copper. Understanding electrolysis is crucial for determining how ions are transformed during the plating process.

Faraday's Laws of Electrolysis

Faraday's Laws of Electrolysis describe the relationship between the amount of substance transformed at an electrode and the quantity of electric charge passed through the electrolyte. The first law states that the mass of a substance deposited is directly proportional to the charge passed, which is essential for calculating the time required for electroplating a specific mass of copper.

Current and Charge

Current (measured in amperes) is the flow of electric charge, and it plays a vital role in electrolysis. The total charge (Q) can be calculated using the formula Q = I × t, where I is the current and t is the time. This relationship allows us to determine how long it will take to deposit a certain mass of copper based on the current applied.