AP Chem Faraday law electrolysis cheat sheet

Define electrolysis.

Electrolysis is a chemical process that uses electrical energy to drive a non-spontaneous reaction.

What is Faraday's First Law?

Faraday's First Law states that the amount of substance transformed at an electrode is proportional to the charge passed.

True or False: Electrolysis occurs in a solid conductor.

False. Electrolysis requires an electrolyte solution or molten ionic compound.

Identify the products of water electrolysis.

Hydrogen gas at the cathode and oxygen gas at the anode.

Fill in the blank: Faraday's constant is approximately ____ C/mol.

96500 C/mol.

What is Faraday's Second Law?

Faraday's Second Law states that the mass of substance produced is proportional to the charge divided by the number of electrons transferred.

Cause → Effect: High current density in electrolysis.

Leads to increased reaction rates and potential overheating.

Comparison: Cathode vs. Anode.

Cathode: Reduction occurs; Anode: Oxidation occurs.

What is an electrolytic cell?

An electrolytic cell is a device that uses direct current to drive an otherwise non-spontaneous chemical reaction.

List two applications of electrolysis.

- Electroplating - Production of chlorine and hydrogen

Calculate the mass of Cu deposited from 10 A for 1 hour.

Using $\displaystyle m = \frac{Q}{F} imes M$, where $\displaystyle Q = I imes t = 10 imes 3600$, Cu molar mass = 63.5 g/mol.

Explain the role of the electrolyte.

The electrolyte conducts electricity and facilitates ion movement during electrolysis.

Faraday's First Law of Electrolysis

The mass of substance produced at an electrode is proportional to the charge passed. Formula: m = kQ, where k is a constant.

Calculate charge using moles of electrons

Charge (Q) can be calculated using: Q = nF, where n = moles of electrons, F = Faraday's constant (96485 C/mol).

What is Faraday's constant?

Faraday's constant (F) is approximately 96485 C/mol, representing the charge of one mole of electrons.

True or False: 1 mole of electrons equals 1 Coulomb.

False. 1 mole of electrons equals 96485 Coulombs.

How to find moles from charge?

Use the formula: n = \frac{Q}{F}, where Q is charge in Coulombs.

What does k represent in electrolysis calculations?

k represents the electrochemical equivalent, indicating mass produced per unit charge.

Fill in the blank: The total charge (Q) in electrolysis is given by __________.

Q = nF, where n is moles of electrons.

Calculate moles from mass

Using the formula: n = \frac{m}{M}, where m = mass, M = molar mass.

What is the relationship between current and charge?

Charge (Q) is the product of current (I) and time (t): Q = It.

Cause → Effect: Increasing current in electrolysis.

Increased current results in faster reaction rates and more substance produced at electrodes.

How to calculate time for electrolysis?

Using: t = \frac{Q}{I}, where Q is charge, I is current.

Compare anode and cathode in electrolysis.

Anode: oxidation occurs; Cathode: reduction occurs.

What does the total charge depend on?

Total charge depends on current and time, represented as Q = It.

True or False: Time is directly proportional to charge in electrolysis.

True. More time allows more charge to flow.

Worked example: Calculate charge for 0.5 moles of electrons.

Q = nF = 0.5 moles * 96485 C/mol = 48242.5 C.

Fill in the blank: The electrochemical equivalent (k) is expressed in __________.

grams per Coulomb (g/C).