3.2 Solubility of Ionic Compounds

Question 1

What is solubility?

Answer 1

amount of a substance that will dissolve in a certain volume of a specific solvent at a given temperature (g/L or mol/L)

Question 2

What is the degree of solubility of a soluble compound?

Answer 2

10 g or more can dissolve in a litre of solvent

Question 3

What is the degree of solubility of a slightly soluble compound?

Answer 3

0.1 to 10 g can dissolve in a litre of solvent

Question 4

What is the degree of solubility of an insoluble compound?

Answer 4

less than 0.1 g can dissolve in 1 L of solvent

Question 5

How does solubility relate to temperature?

Answer 5

directly proportional

Question 6

What is a solvent?

Answer 6

a liquid or gas that dissolves another solid, liquid, or gas

Question 7

What is a solute?

Answer 7

substance that dissolves in a solvent

Question 8

What occurs when an ionic solid dissolves in water?

Answer 8

dissociates into hydrated (solvated) ions

Question 9

What is a saturated solution?

Answer 9

point where dissociation stops because an equilibrium between the undissolved solid and the free ions is reached

Question 10

What is the solubility product constant (Ksp)?

Answer 10

[A]^a[B]^b

where A and B are products

Question 11

Why is Ksp a product?

Answer 11

reactant is a solid which aren’t used for equilibrium constants

Question 12

How does solubility related to Ksp value?

Answer 12

very soluble = large Ksp

Question 13

When is a one way arrow used for solubility? double arrow?

Answer 13

one-way for very soluble/large Ksp is one way arrow because these dissolutions essentially go to completion

double arrow used for compounds with low solubility

Question 14

Why is there no impact of excess solid on the equilibrium position?

Answer 14

more solid = more surface area = increase rate of dissolution but also = more rate of precipitation so there is no effect on the equilibrium position

Question 15

What is an unsaturated solution?

Answer 15

quantity of a species in solution is less that that required for equilibrium with the solid

Question 16

What does it mean for Q = Ksp?

Answer 16

reaction quotient = solubility constant
–> saturated solution: system is at equilibrium so max ion concentration is reacted so there is some solid

Question 17

What does it mean for Q < Ksp?

Answer 17

no solid present so all ions will remain in solution – unsaturated solution

Question 18

What does it mean for Q > Ksp?

Answer 18

a solid will be formed from ions In solution – precipitation reaction – supersaturated – [ion] too high

Question 19

What is the common ion effect?

Answer 19

presence of a common ion between the solute and solvent will reduce the amount of solid that will dissolve

Question 20

What is dissolution?

Answer 20

action of breaking a substance apart and dispersing it in another phase to form a solution (homogenous mixture)

Question 21

How are dissolution and entropy related?

Answer 21

dissolution increases entropy especially when a highly ordered crystal structure is dispersed into a solution

Question 22

How can you determine ion charges?

Answer 22

one main group elements acquire a noble gas electron configuration as ions:
ex. F-, Br-, O2-, S2-, Be2+, Mg2+, Li1+, Na1+, Al3+