C3.6

Question 1

Define solvent

Answer 1

A substance that dissolves other substances (called solutes)

Question 2

Define solute

Answer 2

A substance which is dissolved in a solvent. The end result of this is a solution.
NB. The amount of solute that dissolves depends on the solvent’s temperature.

Question 3

Define saturated solution

Answer 3

A solution which is in equilibrium with undissolved solute.

Question 4

Define solubility

Answer 4

The extent to which a solute will dissolve in a solvent.

Question 5

What is Ks?

Answer 5

Likelihood of a solute to dissolve. Large numbers more likely.

Question 6

What is the Ks equation for AB?

Answer 6

Ks = [A+] [B-]

Question 7

What do square brackets represent?

Answer 7

The concentration.

Question 8

What can solubility constants be used for?

Answer 8

• Calculate c of one ion in eq with another
• Determine if a ppt will form when two solutions are mixed
• Calculate solubility of ionic compound

Question 9

How do you calculate Ks for AB from solubility?

Answer 9

Ks = [A+] [B-]
As A=B
Ks = [A+] squared. (or [B-] squared)

Question 10

How do you calculate Ks for A2B from solubility?

Answer 10

Ks = [A+] squared x [B-]

As 2:1 ration of A:B, multiply A by 2 before squaring.

Question 11

How do you calculate Ks for AB2 from solubility?

Answer 11

Ks = [A+] x [B-] squared.

As 1:2 ratio of A:B, multiply B by 2 before squaring.

Question 12

How do you calculate solubility for AB from Ks?

Answer 12

x = root of Ks

Question 13

How do you calculate solubility for A2B or AB2 from Ks?

Answer 13

x = cube root (Ks/4)

Question 14

What is ionic product?

Answer 14

The concentration of each ion in ppt multiplied together.

Question 15

How do you know if a reaction will form a precipitate?

Answer 15

If Ionic product is larger that Ks, ppt will be formed.

Question 16

What happens if equal volumes of two solutions are combined?

Answer 16

The concentration of each solution halves.

Question 17

What is the common ion effect?

Answer 17

The drop in solubility of AB if A+ or B- ions are added from another source.

Question 18

What happens if A+ or B- ions are added to an AB solution?

Answer 18

The equilibrium will shift to favor the ppt as higher conc. of ions.

Question 19

What are acids and bases relative to protons?

Answer 19

An acid is a proton donor, a base is a proton acceptor.

Note: A does not match A (acid acceptor)

Question 20

What do strong acids and strong bases do in water?

Answer 20

They completely dissociate in water, fully releasing all of their ions.

Question 21

What do weaker acids and bases do in water?

Answer 21

They do not dissociate fully in water, and only partially ionize.

Question 22

What is Ka?

Answer 22

The acid dissociation constant

Question 23

How do you calculate Ka?

Answer 23

[products]/[reactants]

Question 24

How do you calculate the final conc. of an acid in solution?

Answer 24

acid - [H3O+]

Question 25

What does a small Ka mean?

Answer 25

The acid is weak

Question 26

What does a large Ka mean?

Answer 26

The acid is strong

Question 27

What does a small pKa mean?

Answer 27

The acid is strong

Question 28

What does a large pKa mean?

Answer 28

The acid is weak

Question 29

What is Kb?

Answer 29

The symbol for the dissociation constant for a base- to what extent a base will dissociate.

Question 30

What does the strength of an acid depend on?

Answer 30

The extent to which it will donate protons

Question 31

What does the strength of a base depend on?

Answer 31

The extent to which it will accept protons.