Ch 11: Oxidation-Reduction Reactions Flashcards Preview

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Flashcards in Ch 11: Oxidation-Reduction Reactions Deck (20):


loss of electrons



gain of electrons


oxidizing agent

facilitates the oxidation of another compound and is reduced itself in the process


reducing agent

facilitates the reduction of another compound and is itself oxidized in the process


common oxidizing agents almost all contain

oxygen or a similarly electronegative element


common reducing agent often contain

metal ions or hydrides (H-)


any free element or diatomic species has an oxidation number of



the oxidation number of a monatomic ion is equal to

the charge of the ion


when in compounds, the group IA metals have an oxidation



in compounds, Group IIA metals have an oxidation number of



Group VIIA elements in compounds have an oxidation number of

unless combined with an element with higher electronegativity


oxidation state of hydrogen is +1 unless paired with a less electronegative element, in which case its

- 1


oxidation state of oxygen is usually -2, except in

peroxides (when its charge is -1) or in compounds with more electronegative elements


the sum of the oxidation numbers of all atoms present in a compound is equal to

the overall charge of the compound


when balancing redox reactions, the half reaction method also called the ion-electron method is most common

seperate the two half reactions, balance each starting with H and O. In acidic, balance with water. In base, balance H and O using water and OH.

balance the charges of each half-reaction by adding electrons as necessary to one side of the reaction.

multiple the half-reactions as necessary to obtain the same number of electrons in both half-reactions

add the half-reactions, cancelling out terms on both sides of the reaction arrow

confirm the mass and charge balanced


complete ionic equation

accounts for all of the ions present in a reaction. to write a complete ionic reaction, split all aqueous compounds into their relevant ions. Keep solid salts intact.


net ionic equations

ignore spectator ions to focus only on the species that actually participate in the reaction. to obtain a net ionic reaction, subtract ions appearing on both sides which are spectator ions.

reaction with no aq salts, the net ionic equation is generally the same as the overall balanced reaction

double displacement (metathesis) reactions that do not form a solid salt, there is no net ionic reaction because all ions remain in solution and do not change oxidation number


disproportionation (dismutation) reactions

type of redox reaction in which one element is both oxidized and reduced, forming at least two molecules containing the element with different oxidation states


oxidation-reduction titrations

similiar in methodology to acid-base titrations. these titrations follow transfer of charge.

indicators used in such titrations change color when certain voltages of solutions are achieved

potentiometric titration under this


potentiometric titration

form of redox titration in which a voltmeter or external cell measures the electromotive force (emf) of a solution. No indicator is used, and the equivalence point is determined by a sharp change in voltage