Precipitation
Volumetric Glassware
to contain (TC)
to deliver (TD)
not all ionic compounds equally water soluble:
soluble, partially soluble, insoluble
solubility at 20 oC
volumetric flask
pipet
buret
NaCl
MgCl2
365 g/L
543 g/L
soluble
PbCl2
9.90 g/L
insoluble
PbI2
AgCl
PbS
0.63 g/L
0.0091 g/L
0.00086 g/L
Solubility Rules
Important, Insoluble, Ionic Compounds
CaO
empirical predictions rules; apply in order:
HgS
1. all Na+, K+, and NH4+ compounds (salts) soluble
Ca3(PO4)2
CdS
CaCO3
2. all NO3–, C2H3O2–, ClO3– and ClO4– salts soluble
3. all Ag+, Pb2+, and Hg22+ salts insoluble
PbCrO4
4. all Cl–, Br–, and I– salts soluble
BaSO4
Fe2O3
Mg(OH)2
AgBr
5. all CO32–, O2–, S2–, OH–, SO32–, CrO42–, and PO43– salts
insoluble, except CaS, SrS, BaS and Ba(OH)2
6. all SO42– salts soluble except CaSO4, SrSO4, and BaSO4
Acid – Base Definitions
Acids
Ancient acid: litmus red, sour, corrosive, react with bases  salts
base: litmus blue, bitter, slippery, react with acids
recognize: contains H+, given first
Svante
acid: substance that H+ (protons) in water
base: substance that OH– in water
Arrhenius
1884
connected by: H+(aq) + OH–(aq)
X–
M+
Johannes Thomas
Brønsted-Lowry
1923
H2O(ℓ)
MX salt
acid: proton donor (to base)
base: proton acceptor (from acid)
HCl(g) + NH3(g)
Cl– + NH4+
H2C2O4 oxalic
diprotic
HC2H3O2 acetic
monoprotic
–ide
–ite
–ate
hydro–ic
–ous
–ic
CN– cyanide
ClO2– chlorite
SO42– sulfate
H3C6H5O7 citric
triprotic
HCN
hydrocyanic acid
HClO2 chlorous acid
H2SO4 sulfuric acid
Strong (SA): strong electrolytes
hydrochloric acid
hydrobromic acid
hydroiodic acid
nitric acid
HCl(aq)
HCl
HBr
HI
HNO3
H+(aq) + Cl–(aq)
chloric acid
HClO3
perchloric acid
HClO4
sulfuric acid
H2SO4
Weak (WA): weak electrolytes
HC2H3O2(aq)
H+(aq) + C2H3O2–(aq)
acetic acid and every other acid!
1
Indicators
Bases
change color with excess H+ or OH–
more acidic
NaOH
OH–
Na+ + OH–
Ca(OH)2
Ca2+ + 2 OH–
KOH
Mg(OH)2
Al(OH)3
Al3+ + 3 OH–
Fe(OH)3
RbOH
Ba(OH)2
Weak (WB)
NH4+(aq) + OH–(aq)
NH3(aq) + H2O(ℓ)
neutral
alizarian yellow R
thymolphthalein
thymol blue (base)
phenolphthalein
phenol red
bromothymol blue
chlorophenol red
bromocresol green
methyl orange
bromophenol blue
thymol blue (acid)
methyl violet
Strong (SB): ionic hydroxides
ammonia
more basic
hydrangea
fruit, flower and leaf pigments:
acid
Fall Colors
Chlorophylls
base
Fall Colors
Flavonols, Flavones, and Anthocyanins
acid-base indicators
Carotenoids and Xanthophylls
OH
OH
OH
N
N
O
O
HO
O
Mg N
OH
OH
N
O
OH
O
HO
O
OH
O
O
O
OH
OH
HO
O+
OH
OH
OH
OH
HO
Acid-Base Titration
titration:
indicator:
equivalence point:
end point:
Oxidation State (OS) Rules
known M added to unknown M
shows end point
when reaction is complete (stoichiometry)
when color changes; just past equiv. pt.
base
O
OH
O
O
O
OH
colorless
acid
2 NaOH(aq) + H2SO4(aq)
xs acid
OH
O–
xs base magenta
1. element OS = 0
2. monatomic ion charge = OS (separate ions)
3. part of compound or polyatomic ion:
a. F always –1
b. H +1 (first) or –1 (with M)
c. O usually –2
4. OS sum  compound = 0/polyatomic ion = charge
Na2SO4(aq) + 2 H2O(ℓ)
Cu + 4 H+ + 2 NO3–
Cu2+ + 2 NO2 + 2 H2O
2