General Chemistry Chapter 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 (usually contain oxygen or similar electronegative element)

Question 4

Reducing agent

Answer 4

facilitates the reduction of another compound and is itself oxidized in the process (often contain metal or hydrides)

Question 5

Oxidation number of any free element or diatomic species

Answer 5

0

Question 6

Oxidation number of a monatomic ion

Answer 6

equal to the charge of the ion

Question 7

Oxidation number of Group IA metals in compound

Answer 7

+1

Question 8

Oxidation number of Group IIA metals in compounds

Answer 8

+2

Question 9

Oxidation number of Group VIIA elements

Answer 9

-1 (unless paired with a higher electronegativity)

Question 10

Oxidation number of hydrogen

Answer 10

+1 unless it is paired with a less electronegative element, in which case it is -1

Question 11

Oxidation number of oxygen

Answer 11

usually -2, except in peroxides (when its charge is -1) or in compounds with more electronegative elements

Question 12

The sum of all oxidation numbers =

Answer 12

overall charge of the compound

Question 13

What are the steps to the half-reaction method?

Answer 13

1. Separate the two half-reactions
2. Balance the atoms of each half-reaction. Start with all the elements besides H and O. In acidic, balance H and O using water and H+. In basic, balance using water and OH-
3. Balance the charges by adding electrons
4. Multiply the half-reactions as necessary to obtain same number of electrons
5. add the half-reactions, canceling out terms on both sides of the reaction arrow.
6. Confirm mass and charge are balanced.

Question 14

Complete ionic equation

Answer 14

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 15

Net ionic equations

Answer 15

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

Question 16

For reactions that contain no aqeous salts, the net ionic equation:

Answer 16

is generally the same as the overall balanced reaction.

Question 17

For double displacement reactions that do not form a solid, the net ionic reaction:

Answer 17

does not exist because all ions remain in solution and do not change oxidation number.

Question 18

Disproportionaton 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

similar methodology - follow transfer of charge

- change color when certain voltages of solutions are achieved.

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.