© University of South Carolina Board of Trustees Common Ion Effect MgCO 3 has a K sp = 2.6 x10 −5 in water. What is its solubility in pure water? s = 5.1

© University of South Carolina Board of Trustees

Common Ion Effect

MgCO3 has a Ksp = 2.6 x10−5 in water.

What is its solubility in pure water?s = 5.1 x10−3 M

What is its solubility in a 0.30 M MgCl2 aqueous solution?

s = 8.6642 x10−5 M (quad. eq.)

s = 8.6667 x10−5 M (approx.)


Common Ion Effect: Not so Common

MgCO3 has a Ksp = 2.6 x10−5. What is its solubility in a 0.30 M NaCl solution?

MgCO3 has a Ksp = 2.6 x10−5. What is its solubility in a 0.30 M MgCl2 solution?


Chapt. 14Chemical Equilibrium

Sec. 7Will a Precipitate Form?

Will a Precipitate Form?

25.00 mL of 0.050 M Na2CO3 and25.00 mL of 0.0020 M Ca(NO3)2 are mixed. Will a precipitate form?

Identify the most likely precipitate(Table 4.1)

Find initial concentrations

Q vs Ksp


Chapt. 15 Acids and Bases

Sec. 1Definitions


Bronsted-Lowry Acids and Bases

Acid (A): proton donor

Base (B): proton acceptor

AH + B A− + BH+

proton transfer

H+


Arrhenius vs Bronsted-Lowry

Arrhenius Acid: Source of H+ in water

Base: Source of OH− in water

Bronsted-Lowry Acid: Donates H+ from a base

Base: Accepts H+ from an acid

Lewis

Sec. 15.9 (skip)


Acids (proton donors)

HClHCl + B Cl- +HB+



HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+



HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+

H2SO4

H2SO4 + B HSO4- + HB+



HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+

H2SO4


HSO4-

HSO4- + B SO4

2- + HB+



HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+

H2SO4


HSO4-

HSO4- + B SO4

2- + HB+

H3O+

H3O+ + B H2O + HB+



HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+

H2SO4


HSO4-

HSO4- + B SO4

2- + HB+

H3O+

H3O+ + B H2O + HB+

H2OH2O + B OH- + HB+



HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+

H2SO4


HSO4-

HSO4- + B SO4

2- + HB+

H3O+

H3O+ + B H2O + HB+


Bases (proton acceptor)

NH3

NH3 + AH NH4+ + A-



HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+

H2SO4


HSO4-

HSO4- + B SO4

2- + HB+

H3O+

H3O+ + B H2O + HB+



NH3

NH3 + AH NH4+ + A-

OH-

OH- + AH H2O + A-



HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+

H2SO4


HSO4-

HSO4- + B SO4

2- + HB+

H3O+

H3O+ + B H2O + HB+



NH3

NH3 + AH NH4+ + A-

H2OH2O + AH H3O+ + A-

OH-

OH- + AH H2O + A-



HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+

H2SO4


HSO4-

HSO4- + B SO4

2- + HB+

H3O+

H3O+ + B H2O + HB+



Cl-

Cl- + AH HCl + A-

NH3

NH3 + AH NH4+ + A-


OH-

OH- + AH H2O + A-



HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+

H2SO4


HSO4-

HSO4- + B SO4

2- + HB+

H3O+

H3O+ + B H2O + HB+



Cl-Cl- + AH HCl + A-

NH3

NH3 + AH NH4+ + A-

SO42-

SO42- + AH HSO4

- + A-


OH-

OH- + AH H2O + A-



HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+

H2SO4


HSO4-

HSO4- + B SO4

2- + HB+

H3O+

H3O+ + B H2O + HB+




NH3

NH3 + AH NH4+ + A-

HSO4-

HSO4- + AH H2SO4 + A-

SO42-

SO42- + AH HSO4

- + A-


OH-

OH- + AH H2O + A-


Conjugate Acid-Base Pairs

AH + B A- + HB+

acid base conj.base

conj.acid


Conjugate Acid

HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+

H2SO4


HSO4-

HSO4- + B SO4

2- + HB+

H3O+

H3O+ + B H2O + HB+


– Base Pairs


NH3

NH3 + AH NH4+ + A-

HSO4-


SO42-

SO42- + AH HSO4

- + A-


OH-

OH- + AH H2O + A-


HCN + H2O CN− + H3O+

Example: Identify Acids and Bases



HCN is the acidH2O is the base




HCN is the acid CN- is its conjugate baseH2O is the base H3O+ is its conjugate acid





CH3COO- + H2O CH3COOH + OH−





CH3COO- + H2O CH3COOH + OH−

CH3COO− is the base

H2O is the acid





CH3COO− + H2O CH3COOH + OH−

CH3COO− is the baseCH3COOH is its conjugate acid

H2O is the acid OH− is its conjugate base



HNO2 + H2O NO2- + H3O+

CH3NH2 + H2O CH3NH3+ + OH-

Students: Identify Acids and Bases



HNO2 is the acid NO2- is its conjugate base

H2O is the base H3O+ is its conjugate acid








CH3NH2 is the baseCH3NH3

+ is its conjugate acidH2O is the acid OH- is its conjugate base







CH3NH2 is the baseCH3NH3

+ is its conjugate acidH2O is the acid OH- is its conjugate base



Amphoteric

HClHCl + B Cl- +HB+

NH4+

NH4+ + B NH3 + HB+

H2SO4


HSO4-

HSO4- + B SO4

2- + HB+

H3O+

H3O+ + B H2O + HB+


Compounds


NH3

NH3 + AH NH4+ + A-

HSO4-


SO42-

SO42- + AH HSO4

- + A-


OH-

OH- + AH H2O + A-


Amphoteric =

Acts as both acid and base

HSO4- + B SO4

2- + HB+

HSO4- + HA H2SO4 + A-


Amphoteric =

Acts as both acid and base

HSO4- + B SO4

2- + HB+

HSO4- + HA H2SO4 + A-

H2PO3- + B HPO3

2- + HB+

H2PO3- + HA H3PO3 + A-


Definitions

Proton

Acid Base

Conjugate Acid Conjugate Base

Amphoteric


Chapt. 15Acids and Bases

Sec. 2Water


Autoionization of Water(Amphoteric)

base

H+

acid

H2O(l) + H2O(l)

Kw = [H3O+] [OH-] = 1.0 x10-14

(at 24 C)

H3O+(aq) + OH-

(aq)


pX Notation

[OH-] = 10-pOH

X = 10-pXpX = - log10 X

pH = - log [H3O+] [H3O+] = 10-pH

pOH = - log [OH-]

pKw = - log Kw Kw = 10-pKw

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© University of South Carolina Board of Trustees Common Ion Effect MgCO 3 has a K sp = 2.6 x10 −5 in water. What is its solubility in pure water? s = 5.1