Chemistry Video 9

Question 1

Dissolution

Answer 1

One substance dissolves into something else. Solute is being dissolved and solvent is what the solute is being dissolved into.

Question 2

Aqueous solution

Answer 2

If the solvent is water, then it is an aqueous solution.

Can be covalent solute. Phase change will occur (i.e. solid to aqueous phase).

Can be ionic solute. The compound will have complete dissociation. Phase change will occur (i.e. solid to aqueous phase).

Question 3

Water immiscible substance

Answer 3

Solids that are water insoluble will not form solutions. The solid does not dissolve.

Hydrophobic or non polar substances also will not form an aqueous solution, such as oil with water.

Question 4

Electrolyte

Answer 4

A substance that produces ions in solution and conducts electricity

More dissociation = stronger electrolyte

Question 5

Non-electrolyte

Answer 5

A substance that does not dissociate into ions in solution and does not conduct electricity. Water insoluble substances.

Question 6

Strong electrolyte

Answer 6

Complete dissociation of a substance in solution. Conducts electricity very well

Question 7

Weak electrolyte

Answer 7

Partial dissociation of a substance in solution. Still conducts electricity, but not as well as strong electrolytes

Question 8

Electrical conductance

Answer 8

Can be measured for aqueous solutions to categorize substances as being strong, weak or non-electrolyte

Question 9

Freely mobile charged species

Answer 9

Needed in order for a substance to conduct electricity. i.e. metallic wires allow for the free movement of electrons

In solution, freely mobile charged species are the ions from a substance that have been dissociated. The more ions in solution, the greater the conductivity and the stronger the electrolyte.

Question 10

Ionic electrolyte

Answer 10

Ionic compounds that dissociate in aqueous solution to give individual cations and anions. The cations and ions make ion-dipole interactions with the water molecules that comprise the solvent. Ions are dispersed throughout the solution to maximize solvation and ion-dipole interactions.

Occurs for most ionic solids. Ionic solids tend to be strong electrolytes

Question 11

Solubility rules

Answer 11

Rule 1: Salts containing group 1 metal ions and ammonium ion NH4(+) are water soluble.

Rule 2: Salts of nitrate NO3(-), chlorate ClO3(-), perchlorate ClO4(-) and acetate CH3CO2(-) are water soluble.

Rule 3: Salts of silver Ag (+), lead Pb (2+) and mercury Hg (+) are water insoluble, unless the rule 2 anions are present.

Rule 4: Salts of hydroxide HO(-), carbonate CO3(2-), phosphate PO4 (3-) and sulphide S(2-) are water insoluble, unless rule 1 cations are present.

…. sulfates SO4 (2-) are soluble too

Question 12

Covalent electrolytes

Answer 12

These covalent substances undergo chemical reaction with the solvent molecules in solution to form charged products. These are usually strong acids or strong bases that either donate a proton to a water molecules or remove a proton from a water molecule.

Question 13

Net ionic equation

Answer 13

Splitting a chemical equation into its separate ions. There are spectator ions on both sides of the equation that do not participate in chemistry; they just sit in solution; they can be cancelled out.

Finally, after cancelling out spectator ions and getting the smallest ratio of ions or molecules, you will have a condensed equation

Question 14

Types of double displacement reactions

Answer 14

1. Precipitation reactions
2. Gas-forming reactions
3. Neutralization reactions (acid and base reactants)

Question 15

Molarity

Answer 15

Moles solute / liters solution

Question 16

Normality

Answer 16

Can refer to polyprotic acids, which can deprotonate multiple times.

The normality of a polyprotic acid is the molarity multiplied by the amount of times the polyprotic acid can deprotonate.

It can also refer to certain bases.

The normality of a base is the molarity multiplied by the amount of (OH) that the base has

Question 17

Dilution

Answer 17

Concentration of solute decreases by adding more solvent. Moles of solute is constant.

M1V1 = M2V2

Question 18

Redox reactions

Answer 18

Oxidation-reduction reactions. Can be shown by half reactions (one oxidation, one reaction), which shows electron transfer.

Question 19

Reducing agent

Answer 19

The substance being oxidized

Question 20

Oxidizing agent

Answer 20

The substance being reduced

Question 21

Assigning oxidation numbers

Answer 21

1. Elements = 0, monoatomic ions = charge on ion
2. H = +1 (except for hydrides that are -1)
3. O = -2 (except for peroxides that are -1)
4. Halogens = -1
5. Oxidation numbers must add up to 0 (or add up to the formal charge if it is an ion)