Solutions: Equations

Question 1

Percent composition by mass = ?

Answer 1

Mass of solute / Mass of SOLUTION x 100

Question 2

Molarity = M = ?

Answer 2

Moles of solute / Liters of SOLUTION

Question 3

Molality = m = ?

Answer 3

Moles of solute / Mass of SOLVENT (kg)

Question 4

When does m = M ?

Answer 4

For dilute aqueous solutions at 25 degree C

Question 5

Dilution formula = ?

Answer 5

M1.V1 = M2.V2

Question 6

Glucose molecular weight = ?

Answer 6

180 g/mol

Question 7

MX: Ksp = ?

Answer 7

x^2

Question 8

MX2: Ksp = ?

Answer 8

4x^3

Question 9

MX3: Ksp = ?

Answer 9

27x^4

Question 10

How to calculate the solubility when there is already a little of one of the ions in the solution?

Answer 10

Write down: Ksp = [M]^a . [X]^b = (x)^a . (x + [X from solution])^b
Note that x in the second parentheses is negligible; therefore rewrite: Ksp = [M]^a . [X]^b = (x)^a . ([X from solution])^b
Solve for x

Question 11

Raoult’s Law = ?

Applies to?

Answer 11

Pa = Xa . Pa (in its pure state)

Ideal solutions

Question 12

Boiling point of water in terms of pressure?

Answer 12

1 atm

Question 13

Boiling point elevation equation = ?

Answer 13

Delta Tb = i.Kb.m

Question 14

Freezing point depression equation = ?

Answer 14

Delta Tf = i.Kf.m

Question 15

Osmotic pressure = ?

Answer 15

i.M.R.T

Question 16

When given a list of Ksps, how do I find the compound that is most soluble in water?

Answer 16

1. First compare compounds that have the “same” formula: MX, MX2, MX3…
2. Then compare them to each other by calculating x

Question 17

What is Kf?

Answer 17

The stability constant = opposite of Ksp = [complex ion]/[reactant 1].[reactant 2]