Chapter 9 - Oxidization-Reduction Reactions

Question 1

what is an important characteristic in many reactions?

Answer 1

electron transfer

Question 2

when reactions transfer electrons, what 3 characteristics do they have?

Answer 2

one entity gains electrons, one entity loses electrons, total number of electrons gained and lost are equal

Question 3

define oxidation

Answer 3

the process by which one or more electrons is lost by a chemical entity

Question 4

define reduction

Answer 4

the process in which one or more electrons is gained by a chemical entity

Question 5

define oxidation-reduction reaction

Answer 5

the reaction in which one or more electrons are transferred between chemical entities

Question 6

what is another word for oxidation-reduction reaction

Answer 6

redox reaction

Question 7

what form is the total ionic equation in?

Answer 7

spectator ions are included and all aqueous solutions are written as dissociated ions

Question 8

what form is the total ionic equation in?

Answer 8

write total ionic equation and remove spectator ions

Question 9

define half-reaction equation

Answer 9

the part of an oxidation-reduction reaction equation representing either the oxidation or the reduction reaction

Question 10

define oxidation number

Answer 10

a number used to keep track of electrons in oxidation-reduction reactions according to certain rules

Question 11

what is oxidation number also known as?

Answer 11

oxidation state

Question 12

what is the proper definition of oxidation number

Answer 12

the apparent net electric charge an atom would have if electron pairs in covalent bonds belonged entirely to the more electronegative atom and the shared electrons were divided equally between identical atoms

Question 13

what does the oxidation number not actually represent?

Answer 13

the actual charge on the atom

Question 14

two rules for assigning oxidation numbers

Answer 14

sum of oxidation numbers of all atoms in an electrically neutral compound must equal zero (zero sum rule), sum of oxidation numbers of all atoms in ions containing two or more atoms must equal the overall charge of the ion

Question 15

oxidation number of a monatomic ion

Answer 15

same as the charge on the ion

Question 16

oxidation number of an atom in its element

Answer 16

0

Question 17

oxidation number of fluorine in its compounds

Answer 17

-1

Question 18

oxidation number of oxygen in its compounds

Answer 18

-2, but -1 in peroxides, when there are two oxygens bonded

Question 19

oxidation number of hydrogen in its compounds

Answer 19

+1 in covalent compounds, but -1 in metal hydrides (hydrogen and a metal)

Question 20

convention when writing oxidation numbers vs actual charges

Answer 20

actual charges put number then sign, in oxidation numbers, write sign and then number

Question 21

what can electrons do in redox reactions?

Answer 21

direct transfer of electrons from one reactant to another or partial transfer in covalent bonds where they shift towards the more electronegative element

Question 22

define oxidization agent

Answer 22

the reactant that is reduced (gains electrons from another substance) and causes oxidization during an oxidation-reduction reaction

Question 23

define reducing agent

Answer 23

the reactant that is oxidized (loses electrons to another substance), and causes reduction during an oxidation-reduction reaction

Question 24

how do we name the reducing/oxidation agent?

Answer 24

specify the whole substance, and not just the element that is oxidized/reduced

Question 25

why do oxidation and reduction reactions have to occur in the same reaction?

Answer 25

during a reaction where an entity is oxidized, the entity loses electrons, represented by oxidation half-reaction, the electrons lost are transferred to another entity, which gains the electrons and becomes reduced, represented b reduction half-reaction, since electrons are exchanged from one half-reaction to the other, both have to occur in the same reaction

Question 26

two ways to balance redox reactions

Answer 26

oxidation numbers method or half-reactions method

Question 27

how do we know a redox reaction has occurred?

Answer 27

if there is a change in the number of oxidation numbers of atoms from the reactant side to the product side

Question 28

where do redox reactions take place and what 2 things does this mean

Answer 28

in aqueous solutions, water molecules may participate, may be acidic, neutral or basic

Question 29

what happens if a redox reaction occurs in acidic solution

Answer 29

H+ (aq) may be participants

Question 30

what happens if a redox reaction occurs in a basic solution

Answer 30

OH- (aq) may be participant