Flashcards
Chemistry 30 Flash Cards {5}
Cards in this deck (39)
- 1Historical DefinitionsReduction: The loss of mass when a metal is refined from its ore
Oxidation: reacting a substance with oxygen (often a metal) - 2Modern DefinitionsReduction: The gain or partial gain of electrons
Oxidation: The loss or partial loss of electrons - 3Half-ReactionsShow how stable substances gain or lose electrons to form their respective charged ions. Can be a reduction half-reaction or an oxidation half-reaction
- 4Net Ionic EquationsTwo half-reactions combined to form a singular equation. Will always be a reduction half-reaction mixed with an oxidation half-reaction
- 5ElectronegativityCan play an important role in the ways that electrons are transferred or shared
- 6Redox ReactionsMust have a reducing agent and an oxidizing agent
One substance is reduced and one substance is oxidized
The net reduction must equal the net oxidation - 7Oxidizing AgentsSubstances that cause oxidation
The substance that is being reduced is the OA because it causes the other to be oxidized - 8Reducing AgentsSubstances that cause reduction
The substance that is being oxidized is the RA because it causes the other to be reduced - 9Redox TableShows the half-reactions of substances and combinations of substances
Shows the relative strengths of OAs and RAs - 10Spontaneous ReactionWhen a reaction occurs naturally and products are formed. The strongest oxidizing agent is on the left side of the equation
- 11Non-Spontaneous ReactionWhen a reaction does not occurs naturally and products are not formed. The strongest oxidizing agent is on the right side of the equation
- 12Oxidation NumbersNumbers assigned to all types of substances as if they were an ionic charge. The rules are:
Elements are 0
Oxygen is (-2) unless it is peroxide or w/ F
Hydrogen is (+1) unless it is a hydride
The oxidation # for an ion is the same as its charge
The oxidation number for a compound is either 0 or its charge - 13Types of Redox QuestionsConstructing a Redox Table
Predicting a Redox Reaction
Balancing Redox Equations (Oxidation numbers or Half-Reactions)
Titration Questions/Redox Stoichiometry - 14Electrochemical CellContains solid electrodes dipping into an electrolyte solution, is composed of two half-reactions (one at each electrode), and allows for a load to use energy (using the flow of electrons)
- 15Electrochemical Cells Must IncludeOxidation Half-Reaction
Reduction Half-Reaction
Net Ionic Equation
Voltage of the Cell.
Line Notation
Labelled Anode
Labelled Cathode
Labelled Electrolyte
Direction of Electron Flow
Ion Movement - 16AnodeA solid electrode that serves as the location of oxidation. Anions migrate toward the anode. Electrons are produced.
- 17CathodeA solid electrode that serves as the location of reduction. Cations migrate toward the cathode. Electrons are consumed.
- 18Types of Electrochemical CellsVoltaic and Electrolytic
- 19Voltaic CellsAre always a spontaneous reaction, even if it is normally non-spontaneous. Always goes from the anode to the cathode. Takes place in two separate containers that are connected with a salt-bridge or porous boundary. Converts chemical energy to electrical energy. Has a positive cell potential.
- 20Electrolytic CellsAlways a non-spontaneous reaction, even if it is normally spontaneous. Always goes from the anode to the cathode. Takes place in one container. Converts electrical energy to chemical energy. Has a negative cell potential.
- 21Dry CellsA carbon cell with a paste electrolyte and carbon rod. A normal battery would be a dry cell.
- 22Alkaline CellsBatteries that improve on long term efficiency compared to a dry cell
- 23Button CellsSmall circular cells that have the cathode on the bottom that is either mercury or silver oxide.
- 24Lead Acid BatteryMultiple cells set up in a series with a lead plate separated with porous material
- 25NicadsNickel cadmium cells that are not efficient because they develop a memory as the reverse reaction becomes harder to do.
- 26Fuel CellsHighly efficient fossil fuel cells that make a continuous energy input and output
- 27Primary CellsNon-reversible reactions which are used and the discarded.
- 28Secondary CellsReversible reactions that store energy and are able to recharge after energy is depleted.
- 29Net VoltageThe sum of reduction and oxidation potential
Listed in the data book by the half-reactions
The sign is reversed when the reaction is reversed - 30Cell PotentialThe energy needed for electrons to move to the cathode
Listed in the data book by the half-reactions
Do not change the signs from original
The cathode — the anode - 31S.H.E.Standard Hydrogen Electrode is the reference point for the net voltage of other half-reactions in the redox table. If the standard is changed, the difference in voltage potential will also stay the same.
- 32Line NotationA way of abbreviating the components of a cell. Single line indicates change is state
Reactants come before the products
Double line indicates a bridge or separation
Anode is written before cathode (oxidation before reduction) - 33Electrolysis of WaterShows how the reduction half -reaction for water and oxidation half-reaction for water join together to create 2H2O=2H2+O2
Remember that Hydrogen ions and hydroxide ions add together to form water - 34Chloride AnomolyWhen the strongest reducing agent is between water and chloride, the chloride half-reaction is used.
- 35Uses for ElectrolysisTo protect precious metals from corrosion
To produce metals from salts
To remove precious metals from other substances - 36Down's CellWhen there is electrolysis of a molten salt and a molten metal is gathered as the product. Has a different set-up and usually has a gas outlet for the other product.
- 37Corrosion Prevention1. Prevent Interaction
2. Paint or Coat metal
3. Galvanize metal - 38Sacrificial AnodesIs also called cathodic protection and uses a stronger reducing agent so a different substance gets oxidized instead.
- 39Cell StoichiometryUses the formula:
Ne = It/F
Faraday's Constant is 96500 C/mol of e-
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- Redox Reactions and Electrochemistry
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- Natasha Gidluck
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