1. Volumetric analysis

2. Chemical equation a A + b B + .... x X + y Y + ... =
reactants
products
a , b … stoichiometric coefficients (numbers)
nA a
nB b =
Stoichiometry - describes the ratio of molecules in chemical reactions

3. Calculations from chemical equations
H2SO NaOH Na2SO H2O
reactants
products
nsulfuric acid 1
nsodium hydroxide 2 =
How much of NaOH is necessary for a full neutralization of 1.5 mol of H2SO4 ?
? mol
5.0 g
The answer: 3 mol
? g
150 mL of 40% sol.
? mL of ...
200 mL of 0.1 M sol.

4. Balancing chemical equations
Reaction: silver nitrate + potassium chromate
nomenclature !
AgNO3
K2CrO4 2
Ag2CrO KNO3
AgNO3 + K2CrO4 2
1) identify the products
2) add stoichiometric numbers - to balance the number of atoms
3) check whether it is correct

5. 2 Ag+ + CrO42- Ag2CrO4 Ionic equations AgNO3 Ag+ + NO3-
aqueous solutions: electrolytes disociate
AgNO3
Ag NO3-
K2CrO K CrO42-
Use only the ions that participate in the reaction!
2 Ag CrO Ag2CrO4
reddish brown precipitate

6. In redox reactions, all is about electrons.
difficult to balance !
And you must be able to do so !
In redox reactions, all is about electrons.
OXIDATION = loss of electrons (increase in oxidation state)
REDUCTION = gain of electrons (decrease in oxidation state)
OXIDATION and REDUCTION are coupled processes!
If something gets oxidized, something else must get reduced.

7. Balancing redox equations
Reaction: Fe MnO4-
KMnO4
potassium permanganate - strong oxidizing agent
oxidizing agent = it has the ability to oxidize the others
 it must get reduced itself
MnO H e Mn H2O
MnO oxidation state of the Mn atom is VII
Mn2+ oxidation state of the Mn atom is II
The change in oxidation state is by 5 (electrons).

8. Balancing redox equations
MnO H e Mn H2O
This "half reaction" is a reduction.
Fe Fe3+ + e-
This "half reaction" is an oxidation.
Let's put both together...
1 x
MnO H e Mn H2O
5 x
Fe Fe3+ + e-
MnO Fe H Mn Fe H2O

9. Volumetric analysis a A + b B + .... x X + y Y + ... = a
The principle is a reaction of:
a sample + a standard solution (with known concentration)
nA a
nB b =
n = c x V a b
cA x VA = x cB x VB

10. Titration a b
cA x VA = x cB x VB

11. Laboratory equipment for titrations
1) pipettes
2) burette
3) flasks

13. Automatic pipettes

14. Indicator is a substance which makes the end point (equivalence point)
of the titration apparent by a change in colour

15. Standardization
= estimation of the accurate concentration of a standard solution
by means of its titration with a primary standard solution
(a very stable solution with known concentration)

16. Titrations methods according to the type of reaction
displacement of ions
a) Neutralization reactions (alkalimetry, acidimetry)
H+ + OH- H2O
b) Formation of precipitate (argentometry)
Me+ + X- MeX (non-soluble precipitate)
c) Formation of complexes (chelatometry, mercurimetry)
Me+ + X- [MeX] (soluble complex)
electron transfer
a) Oxidimetry (manganometry, iodometry)
b) Reductimetry (thiosulphatometry)

17. What to know about? Standard reagent
Standardization (primary standards)
Indication of the equivalence point (titration endpoint)
What kind of samples can be analyzed?

18. Acid base indicators

19. Titration curves

20. Titration curves

21. Titration curves

22. Chelatometry
standard reagent: EDTA
ethylenediaminetetraacetic acid

23. Chelatometry