Multiple Equlibrium Systems

Question 1

Mass balance equations

Answer 1

• show concentration relationships
• coefficients used to balance rxns used in MB equation
• think of as ration/ swapping in final MB so amounts of ions becomes equal in the end

Question 2

Charge balance equations

Answer 2

• equation based on relationship of charge w/in solution
• solutions shift eq until overall net chrg = 0
• amount - chrg = amount + chrg
• only what is charged or contributes to charges
• quantity of charge coefficient of ion concentration 2[x^2+]
• indicates when concentrations not equal bc charges not balanced but will still net to 0

Question 3

Steps to solving multiple equilibrium systems

Answer 3

1. write all reactions
2. determine what unknown is in terms of
3. write k expressions for all rxns and find #’s (if possible)
4. mass balance equation
5. charge balance equation
6. ensure # equations matches # uknowns
7. approximate known values

Question 4

Kw (dissociation constant of water equation)

Answer 4

[H3O+][OH-]

Question 5

Dissociation of water

Answer 5

• 2H2O - H3O+ + OH-
• H+ associates to hydronium quickly, doesn’t last long