![Page 1: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/1.jpg)
Biomedical Science
Health and Society, Malmö University
Sergey Shleev
Chemistry
“Acids, bases, pH, pK, pI”
![Page 2: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/2.jpg)
Antoine Lavoisier (1743 - 1794)
Pioneer of analytical chemistryand chemical nomenclature
”One of the first defenition of acids” 1780
Nitrogen (N2) – kväve – (Greek: “no life”)
Hydrogen (H2) – väte – gas which is “water-former“ (Greek)
Oxygen (O2) – syrgas – gas which is "acid-former“(Greek: “becoming sharp”) H2SO4HClO4
![Page 3: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/3.jpg)
SimpleComplex
Nonmetals[S, P]
Metals[K, Na, Ca]Oxides
acidic[SO2, SO3, P2O5,]
basic[K2O, Na2O, CaO]
Acids
Bases[KOH, NaOH, Ca(OH)2]
Salts[KCl,,NaSO4]
oxoacids[HPO3, H4P2O7, H3PO4
H2SO3, H2SO4]nonoxo[HCl, HF,HCN, H2S]
Hydride
Metals[KH, NaH,
CaH2]
Nonmetals[PH3, SiH4]
Inorganic substances
![Page 4: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/4.jpg)
Svante August Arrhenius (1859 - 1927)
”Theory of electrolytic dissociation” – 1887
Nobel Price in Chemistry – 1903
Arrhenius theory that describes aqueous solutions in terms of acids (which dissociate to give hydrogen ions)
and bases (which dissociate to give hydroxyl ions);the product of an acid and a base is a salt and water
This theory is still involved in our modern understanding ofelectrolytes, electrical conductivity of solutions, etc
HA H+ + A- AOH A+ + OH-
![Page 5: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/5.jpg)
HCl NH4OH
White
smoke
HCl + NH3 = NH4Cl
?
HCl + NH4OH = NH4Cl + H2O
??Al(OH)3 or H3AlO3
???[Al(H2O)6]3+
electrical conductivity of melts?
![Page 6: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/6.jpg)
Johannes Nicolaus Brønsted (1879–1947)
Thomas Martin Lowry (1874–1936)
1923- formulation of the protonic definition ofacids and bases, both in solution and in gas phase
BH+ + OH- B + H2O
![Page 7: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/7.jpg)
Gilbert Newton Lewis (1875–1946)
1923 - the electron-pair theory of acid-base reactions
the donation of electron pairs from bases and the acceptance by acids, rather than protons or other bonded substances
The theory spans both aqueous and non-aqueous reactions
![Page 8: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/8.jpg)
Inorganic substances
SimpleComplex
nonmetals[S, P]
metals[K, Na, Ca]Oxides
acidic[SO2, SO3, P2O5,]
basic[K2O, Na2O, CaO]
Basic hydroxides
[KOH, NaOH]
Salts[NaSO4]
Acidic hydroxides
[HPO3, H4P2O7, H3PO4
H2SO3, H2SO4]
Hydride
metals[KH, NaH]
Amphoteric[Al]
Amphoteric[Al2O3]
Amphoteric
hydroxides
[Al(OH)3]
Nonmetals[PH3, SiH4]
Halides
Metalic[KCl, NaF]
Nonmetalic[HCl, HF]
Chelates[K3Fe(CN)6]
![Page 9: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/9.jpg)
HA H+ + A-
HA+H2O H3O+ + A-
Arrhenius
Brønsted-Lowry
BH+ + OH- B + H2O
acid + base conjugate base + conjugate acid
![Page 10: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/10.jpg)
Strong acid
Week acid
![Page 11: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/11.jpg)
Dissociation of an acid can be written in several possible ways:
HA+ <=> A + H+
HA <=> A- + H+
HA- <=> A2- + H+
Note that in some cases the conjugate base (A, A-, or A2-) has a negative charge and in other cases it does not,
but in all cases it has one less positive charge than the acid.
For convenience, we will always write such reactions asHA <=>H+ + A-
The equilibrium constant (Ka) for the dissociation of a weak acid (often called the dissociation constant):
][]][[
HAHA
Ka
![Page 12: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/12.jpg)
Mathematics
“Logarithms, exponents,and quadratic equations”
![Page 13: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/13.jpg)
exponents
xay
xey
.........718.2e
y a xobserved variable constant controlled variable
Euler's number
![Page 14: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/14.jpg)
Arrhenius law(equation)
RT
Ea
eAk
k A Ea
R T
activation energy(T independent constant; (kJ mol-1)
frequency or pre-exponential factor
temperatue(K)
gas constant(8.3155 J K-1 mol-1)
rate constant ofchemical reaction
![Page 15: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/15.jpg)
Logarithms
Natural logarithm ln(x) – the inverse function to exponential (ex)
log(x) – the inverse function to 10x
So…
xey xy ln
xy 10 xy log
![Page 16: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/16.jpg)
pKa «acid dissociation constant»
pKb «base dissociation constant»
][]][[
HAHA
Ka
alogKpKa
][]][[
BOHBH
Kb
KbpKb log
![Page 17: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/17.jpg)
Kw “self-ionization constant of water”
2H2O H3O+ + OH-
143 10]][[ OHOHKw
LmolOHH /10][][ 7
hydronium hydroxide
ba KKKw
![Page 18: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/18.jpg)
pH «power of hydrogen» HapH log
HHCfa
HCpH log
pOH
OHOHCfa
OHapOH log
OHCpOH log
![Page 19: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/19.jpg)
quadratic equations
x
![Page 20: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/20.jpg)
Henderson–Hasselbalch equation
][
][log
HA
ApKpH a
][
][log
B
BHpKpOH b
![Page 21: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/21.jpg)
)()(
pHdnd
BC
))(
][][
(3.2)(
)(2
HKKC
HHK
pHdnd
a
aAw
Buffer capacity
![Page 22: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/22.jpg)
pI «isoelectic point» the pH at which a particular molecule or surface carries no net electrical charge
For glycine, an amino acid with only one amine and one carboxyl group
221 pKpK
pI
6.06 2.35 9.78
![Page 23: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/23.jpg)
Asp ? 1.99 9.90
Lys ? 2.16 9.06
pI pK1 pK2pKs
3.90
10.54(9.6)
(2.8)
![Page 24: Biomedical Science Health and Society, Malmö University Sergey Shleev Chemistry “Acids, bases, pH, pK, pI”](https://reader033.vdocuments.mx/reader033/viewer/2022051110/551a981d55034643688b6046/html5/thumbnails/24.jpg)
The relative concentrations of the three forms of glycineas a function of pH