Oxidation-Reduction Reactions Flashcards
reactions that involve the transfer of electrons from one chemical species to another
oxidation-reduction reactions (redox)
oxidation-reduction reactions:
loss of electrons
oxidation
oxidation-reduction reactions:
gain of electrons
reduction
oxidation vs reduction mnemonic
LEO the lion says GER: Loss of Electrons is Oxidation, Gain of Electrons is Reduction
oxidation-reduction reactions:
causes another atom to undergo oxidation, while it itself is reduced; almost all contain O or a similarly electronegative atom
oxidizing agent
oxidation-reduction reactions:
causes another atom to undergo reduction, while it itself is oxidized; often contain metal ions or hydrides (H-)
reducing agents
are assigned to atoms in order to keep track of the redistribution of electrons during chemical reactions; 8 rules
oxidation numbers
oxidation rule:
oxidation number of a free element is __
e.g. N2, P4, He
0
oxidation rule:
oxidation number for a monatomic ion is equal to ____
e.g. Cu^2+ = __ and Cl^- = __
the charge (+2 and -1)
oxidation rule:
oxidation number of Group IA elements in a compound are __
+1
oxidation rule:
oxidation number of Group IIA elements in a compound are __
+2
oxidation rule:
oxidation number of Group VIIA elements in a compound are __, except when combined with an element of ____
e.g. in HCl, Cl = __, and in HOCl, Cl = __
-1
higher electronegativity
(-1 and +1)
oxidation rule:
oxidation number of hydrogen in a compound is __, except when combined with an element of ____, in which case it is __
+1
lower electronegativity
-1
oxidation rule:
oxidation number of oxygen in a compounds is __, except in ____, for which the charge on each O is __, and when combined with elements of ____, in which the charge on O is __
-2 peroxides (O(2)^2-) -1 higher electronegativity \+2
oxidation rule:
the sum of oxidation numbers of all atoms present in a neutral compound is __; the sum of oxidation numbers of all atoms present in a polyatomic ion is equal to ____
0
the charge of the ion
used for balancing redox reactions
half-reaction method
half-reaction method:
1) separate the two half-reactions
2) balance atoms of each half titration; in acidic solution, balance H and O using H2O and H+; in basic solution, balance H and O using H2O and OH-
3) balance charges by adding electrons as necessary to one side
4) multiply half-reactions as necessary to obtain same number of electrons in each half-reaction
5) add the half-reactions, canceling out terms on both sides of the arrow
6) confirm mass and charge are balanced
accounts for all ions present in a reaction; split all aqueous compounds into their relevant ions, and keep solid salts intact
complete ionic equation
ignores spectator ions to focus only on the species that actually participate in the reaction; subtract the ions appearing on both sides of the equation (spectator ions)
net ionic equation
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
disproportionation (dismutation)
titrations that follow transfer of charge; indicators used change colors when certain voltages of solutions are reached
oxidations-reduction titrations
type of redox titration in which a voltmeter or external cell measures the electromotive force (emf) of a solution; no indicator is used, instead the equivalence point is determined by a sharp change in voltage
potentiometric titration
