Unit 3

Question 1

Solvent

Answer 1

The substance you have more of. (ex: water)

Question 2

Solute

Answer 2

The substance you have less of. (ex: sodium)

Question 3

Aqueous Solutions

Answer 3

Solutions in which water is the solvent.

Question 4

Non-electrolytes

Answer 4

Do not dissociate in water and do not conduct electricity.

Question 5

Weak-electrolytes

Answer 5

Some dissociation (low conductivity)

Question 6

Strong-electrolytes

Answer 6

Strong acids - some dissociation (high conductivity)

Question 7

Precipitation Reaction

Answer 7

Write balanced net ionic equation showing reactants and products.

Question 8

Solubility Rules

Answer 8

Na+, K+, NH4+, NO3- are all soluble in water

Question 9

Elemental Form Oxidation Rule

Answer 9

An atom in elemental form (Mg, Fe) = Oxidation number is 0

Question 10

Mono-atomic Form Oxidation Rule

Answer 10

Oxidation number is equal to its charge (Mg2+ = +2) (Cl- = -1)

Question 11

Hydrogen Oxidation Rule

Answer 11

+1 when bonded to nonmetal (in front), -1 when bonded to a metal (in back)

Question 12

Electronegative Oxidation Rule

Answer 12

The most electronegative element has an oxidation number equal to its charge as an ion. (BF3, oxidation # for F=-1)

Question 13

Determining Oxidation Numbers

Answer 13

Sum of oxidation numbers for all atoms in a compound must equal the overall charge of the compound (H2O, H=+2 O=-2, Overall = 0)

Question 14

How to find what is oxidized and reduced?

Answer 14

Check oxidation numbers of products/reactants

Question 15

How to structure reduction half reaction?

Answer 15

(ex: HClO3 + 3HNO2 -> KCl + 3HNO3) —–> KClO3 + 6e- -> KCl Oxidation changes from +5 to -1 so it gains 6e-

Question 16

Activity Series

Answer 16

Au -> Pt -> Ag -> Cu -> Fe -> Zn -> Mg -> Ca -> Ba -> K (elements less easily oxidized will oxidize elements that are more easily oxidized)

Question 17

Halogen Displacement Redox Reactions

Answer 17

Diatomic halogens that are bonded to themselves (ex: F2) can oxidize any ions below it in the family

Question 18

Disproportionation Reactions

Answer 18

An element in one oxidation state undergoes both oxidation and reduction, must have an intermediate state.

Question 19

Combustion Reactions

Answer 19

Always results in CO2(g) + H2O(l)

Question 20

Acid Reactions

Answer 20

Acids donate protons in aqueous solutions, NO3- will oxidize metals that H+ cannot

Question 21

Balancing REDOX Reactions in Acidic Solutions

Answer 21

1) Write two unbalanced half reactions
2) Balance all atoms except for O and H
3) Balance for O by adding H20
4) Balance for H by adding H+ ions
5) Balance charge by adding electrons
6) Cross multiply to cancel electrons
7) Add half reactions and cancel like terms

Question 22

Common Reductions in Acidic Solutions

Answer 22

Nitrate (NO3-(aq) -> NO(g)
Permanganate (MnO4-(aq) -> Mn2+(aq))
Dichromate (Cr2O7-2(aq) -> Cr3+(aq))

All above oxidize p and d block metals, sulfite ions, peroxides, and substances w/ lower oxidation state than usual in acidic solutions.

Question 23

Substances with Lower Oxidation States than Usual (ex. 1)

Answer 23

C2O4-2, Carbon has oxidations state of +3
It will oxidize to raise its oxidation state

Question 24

Substances with Lower Oxidation States than Usual (ex. 2)

Answer 24

Some non-metals can raise their oxidation states by bonding with like elements
(Hydrochloric acid + species that is easily reduced)

Question 25

What if two species can be oxidized?

Answer 25

When compounds have p block + d block metals and non metals the metal will be oxidized

Question 26

Basic Solutions Concentrations

Answer 26

Basic solutions have a high concentration of hydroxide ions (OH-)

Question 27

Redox Titrations

Answer 27

Solution w/ an unknown concentration of a species that will be oxidized in the reaction.

Question 28

Equivalence Point

Answer 28

Occurs when equal numbers of moles of the species being oxidized and the species being reduced have combined.