14.3.2 Faraday's Laws of Electrolysis

• What is electrolysis?

  Using current to drive a non-spontaneous reaction
• In electrolysis, oxidation occurs at the cathode.

  False
• In electrolysis, redox reactions involve the transfer of electrons
• Match the process with its location in electrolysis:

  Oxidation ↔️ Anode

  Reduction ↔️ Cathode
• What does Faraday's First Law of Electrolysis state?

  Mass is proportional to charge
• Doubling the charge passed through an electrolyte doubles the mass of metal deposited.
• Faraday's Second Law states that when the same charge passes through different electrolytes, the masses are proportional to their equivalent
• How is equivalent weight calculated?

  Molar mass divided by electrons
• If two metal ions require different numbers of electrons for reduction, the one needing fewer electrons will have a higher mass deposited.
• Match the law with its principle:

  First Law ↔️ Mass is proportional to charge

  Second Law ↔️ Mass is proportional to equivalent weight
• What is the energy source for electrolysis?

  Electric current
• Redox reactions can only occur spontaneously.

  False
• Faraday's First Law states that the mass of a substance deposited is directly proportional to the charge
• What does Faraday's Second Law relate to when the same charge is passed through different electrolytes?

  Equivalent weights
• The equivalent weight of a substance is always lower than its molar mass.
• Steps to calculate the mass deposited using Faraday's Laws

  1️⃣ Identify the redox reaction and number of electrons

  2️⃣ Calculate the equivalent weight

  3️⃣ Use Faraday's First Law to relate mass and charge

  4️⃣ Use Faraday's Second Law to compare masses
• The electrochemical equivalent (ECE) is the mass of a substance liberated by one coulomb
• What is the formula for calculating electrochemical equivalent (ECE)?

  $ECE =$$\frac{A}{nF}$
• What is the electrochemical equivalent (ECE) measured in?

  Grams per coulomb
• The formula for calculating electrochemical equivalent (ECE) is A/nF
• The Faraday constant is approximately 96,485 C/mol.
• What is the valency of copper in the example calculation of ECE?

  2
• What is one factor that influences the outcome of electrolysis?

  Type of electrolyte
• Higher concentrations of an electrolyte increase current carrying capacity.
• Order the factors affecting electrolysis based on their primary influence on the process.

  1️⃣ Type of Electrolyte

  2️⃣ Concentration

  3️⃣ Temperature

  4️⃣ Current Density

  5️⃣ Electrode Material
• What type of reaction is driven by electrolysis?

  Non-spontaneous
• In redox reactions, oxidation occurs at the anode
• What does Faraday's First Law of Electrolysis state?

  Mass is proportional to charge
• If the charge passed through an electrolyte is doubled, the mass deposited also doubles.
• What does Faraday's Second Law of Electrolysis state?

  Masses are proportional to equivalent weights
• The equivalent weight of a substance is calculated as its molar mass divided by the number of electrons
• The Faraday constant is approximately 96,485 C/mol.
• During the electrolysis of copper(II) sulfate, what is the mass of copper deposited if a current of 2 amperes is passed for 30 minutes?

  1.185 grams
• Order the steps to solve a numerical problem based on Faraday's Laws.

  1️⃣ Convert time to seconds

  2️⃣ Calculate the total charge passed

  3️⃣ Determine the number of electrons involved

  4️⃣ Calculate the moles of the substance

  5️⃣ Calculate the mass of the substance