Ch.18 - ElectrochemistryWorksheetSee all chapters
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Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: Calculate the cell potential for the following reaction when the pressure of the oxygen gas is 2.50 atm, the hydrogen ion concentration is 0.10 mol/L, and the bromide ion concentration is 0.25 mol/L.O2(g) + 4H+(aq) + 4Br -(aq) → 2H2O(l) + 2Br2(l)

Problem

Calculate the cell potential for the following reaction when the pressure of the oxygen gas is 2.50 atm, the hydrogen ion concentration is 0.10 mol/L, and the bromide ion concentration is 0.25 mol/L.

O2(g) + 4H+(aq) + 4Br -(aq) → 2H2O(l) + 2Br2(l)

Solution

We are asked to calculate for the standard potential (E°cell) of the reaction. We will use the Nernst Equation to calculate for the ratio. The Nernst Equation relates the concentrations of compounds and cell potential.

E°cell = RTnFlnK

E°cell = cell potential, V
R = gas constant = 8.314 J/(mol
·K)
T = temperature, K
n = mole e- transferred
F = Faraday’s constant, 96485 C/mol e- 
K = equilibrium constant


Let’s first determine how many electrons were transferred in the reaction:

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