Electrochemistry Review

Electrochemistry Review

Electrochemistry Intro Review Week of 11/19/18 Geoff Geberth A shocking amount to know

REDOX Chemistry The main force behind electrochemistry Oxidation Loss of electrons from a species (gets more positively charged) Reduction Gain of electrons from a species (gets less positively/more negatively charged)

OIL RIG Oxidation Is Loss; Reduction Is Gain BOTH processes happen in a reaction. You will have both an oxidation and a reduction The electrons must go somewhere

This is how batteries work Oxidation numbers 0 for all species in an elemental state For a monatomic ion, Ox # = charge Sum of all Ox #s must equal the net charge of the species In compounds, hydrogen is +1 unless bonded to a metal, in which

case it is -1 (such as LiH) The most electronegative element is assigned its charge as an ion (ex: in MgBr2, Br = 1- and therefore Mg = 2+ Unless bonded to another oxygen in a peroxide, oxygen is -2. It is -1 in a peroxide (H2O2) Remember your electronegativity

Utilized from gchem Lets Practice! O = -2; P = +5 O = -2; S = +6

Cl = -1; Fe = +3 Al = +3 (see sulfate above) Na = +1; F = -1; Si = +4 Why do we care? Use oxidation numbers to determine what gets oxidized or reduced in a reaction

Ex: Oxygen takes a -2, so we have -6, therefore Iron becomes +3 to balance. Iron is oxidized, oxygen (going from 0 to -2) is reduced What are the two reactions were dealing with (ignoring stoichiometry)? These are called Half-reactions. They are important for balancing Redox equations

A bit of important nomenclature The species that undergoes reduction is the oxidizing agent and by nature causes oxidation The species that undergoes oxidation is the reducing agent and by nature causes reduction In the previous reaction with iron and oxygen, what are the oxidizing

a reducing agents? Oxidizing agent = Oxygen (is reduced) Reducing agent = Iron (is oxidized) Balancing Redox reactions (the halfreaction method)(acidic conditions) Identify your half reactions For each half reaction, balance all elements EXCEPT hydrogen and oxygen

Balance the oxygens by adding H2O Balance the hydrogens by adding H+ Balance the total charge using electrons (e-) Match the electron count for the two half-reactions by multiplying stoichiometric coefficients of the half-reactions Combine the two reactions to make the overall, cancelling any species on both sides

Check your work to make sure you have the same components on both sides Lets practice In the video game Rainbow 6 Siege, fictional operator Dominic Brunsmeier (codename Bandit) utilizes lead acid batteries in order to electrify surfaces. (RXN =

2 Combine Combine your your balanced balanced half half reactions!

reactions! Far more importantly, lead acid batteries are what you find in standard (non-hybrid or electric) automobiles! Basic conditions First, balance under acidic conditions

Add the same number of OH- ions to the side of the eqn with H+ so that the acid is neutralized into water Add the same number of OH- to the other side of the reaction On the side with both H+ and OH-, cross them out and replace with water (This is the switch from acidic to basic conditions) Cancel any waters that appear on both sides of the equation Double check the balance

Practice in base Initial reaction: Balanced in acid (Do this yourself as an exercise):

Recently Viewed Presentations

  • DC Motors - Cengage

    DC Motors - Cengage

    Perform a rapid assessment of a trucks electrical system. Explain how rotational direction is reversed with a permanent magnet motor. ... brushed DC motors. ... Testing For Open Field Coils. Figure 8-35 Testing for open field coils.
  • Assessing Stage Pictures - Education & Training

    Assessing Stage Pictures - Education & Training

    Each group will be given a scenario which they will have to create a stage picture using what they learned in the workshop involving: 9 parts of the stage, body positions, and levels of meaning. Each group has 3 minutes...
  • Privacy and Information Security Training (2006-07)

    Privacy and Information Security Training (2006-07)

    All faculty and staff who identify themselves with VUMC and/or use their Vanderbilt email address in social media venues such as professional society blogs, Linked In, Facebook, or Twitter for deliberate professional engagement or casual conversation are to follow the...
  • Variables - BARKSDALE SCIENCE

    Variables - BARKSDALE SCIENCE

    Variables that are kept the same throughout the experiment. Manipulated Variable. AKA Independent variable. The variable you CHANGE in order to test your question. Responding Variable. AKA Dependent variable. The variable you . MEASURE. It changes in response to the...
  • PowerPoint-Präsentation

    PowerPoint-Präsentation

    eSciDoc Project eSciDoc is a joint project between the Max Planck Society (MPS) and Fachinformationszentrum (FIZ) Karlsruhe, funded by the Bundesministerium für Bildung und Forschung (BMBF). The aim of the project is the development of a re-usable service infrastructure and...
  • International Development of Futures and Options

    International Development of Futures and Options

    Modern Futures and Options. Started at The Chicago Board of Trade ( CBOT) in 1848. Major sorts of Futures & Options. ... Chicago Mercantile Exchange +Chicago Board of Trade = CME Group. CME Group merged with NYMEX. NYSE Euronext bought...
  • Plants, Isomolar Point, and Water Potential

    Plants, Isomolar Point, and Water Potential

    The ionization constant of sucrose is 1. Round your answer to the tenths place. Practice: What is the water potential of a plant cell with 0.3 M sucrose solution at 20°C? The cell wall applies 2 bars of pressure on...
  • Scientific Method, Measurement, and Graphing

    Scientific Method, Measurement, and Graphing

    Scientific Method. An organized way of using evidence to learn about the natural world . A. Problem . ... Units = km, m, cm, mm . B. Mass- amount of matter in an object, doesn't change . Weight- measure of...