Ch 11: Oxidation-Reduction Reactions

Question 1

oxidation

Answer 1

loss of electrons

Question 2

reduction

Answer 2

gain of electrons

Question 3

oxidizing agent

Answer 3

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

Question 4

reducing agent

Answer 4

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

Question 5

common oxidizing agents almost all contain

Answer 5

oxygen or a similarly electronegative element

Question 6

common reducing agent often contain

Answer 6

metal ions or hydrides (H-)

Question 7

any free element or diatomic species has an oxidation number of

Answer 7

zero

Question 8

the oxidation number of a monatomic ion is equal to

Answer 8

the charge of the ion

Question 9

when in compounds, the group IA metals have an oxidation

Answer 9

+1

Question 10

in compounds, Group IIA metals have an oxidation number of

Answer 10

+2

Question 11

Group VIIA elements in compounds have an oxidation number of

Answer 11

-1

unless combined with an element with higher electronegativity

Question 12

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

Answer 12

• 1

Question 13

oxidation state of oxygen is usually -2, except in

Answer 13

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

Question 14

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

Answer 14

the overall charge of the compound

Question 15

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

Answer 15

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

Question 16

complete ionic equation

Answer 16

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.

Question 17

net ionic equations

Answer 17

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

Question 18

disproportionation (dismutation) reactions

Answer 18

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

Question 19

oxidation-reduction titrations

Answer 19

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

Question 20

potentiometric titration

Answer 20

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