Analytical chemistry

1.What is the science of analytical chemistry?

The science of methods for determining the chemical composition of substances

2. What are cations?

these are positively charged ions

3. How many cation analysis systems are there?

3

4. How to determine the hydrogen index?

pH= -lg [H+]

5. Buffering solutions:

NaH2PO4+Na2HPO4

6. When a little strong alkali is added to an alkaline buffer, its pH...:

Slightly  increases

7. Hydroxides of cations (III) analytical group

insoluble in water

8. What factors affect the value of the electrode potential (Nernst equation)?

acidity of the medium pH

9. Values that are constant in the Nernst equation:

10. What is the geometric shape of the [Cd(NH3)4]2+ complex?

tetrahedron

11. How many ions are produced from the complex Co(NH3)6C12 in solution?

3

12. Which of the above equations correctly describes the behavior of the complex compound K3[Fe(CN)6] in solution:

K3[Fe(CN)6]3K+ + [Fe(CN)6]3-[pic 1]

13. Which one of the following is a weak acid?

HF

14. Which one of the following is a strong electrolyte?

HCl

15. If 100 molecules of salt 40 molecules dissociate into ions, the degree of its dissociation

40

16. The degree of dissociation of 200 salt molecules when 40 salt molecules dissociate into ions

20

17. Qualitative reaction to the Fe2 + cation

FeSO4+2NaOH= Fe(OH)2+Na2SO4

18. The oxidation number of Mn in KMNO4 is

+7

19. What is the purpose of using activity rather than concentration?

Activity is a measure of the effective concentration of a species under non-ideal (e.g., concentrated) conditions

20 . What color precipitate is formed by silver nitrate S2-ions with sulfide anion AgNO3  gives?

black

21. Decrease in the degree of oxidation of an atom or ion by the addition of electrons as it is called?

reduction

22. Group reagent of the first analytical group of cations.

No

23.  II - group reagent of the group:

HCl

24. AgCl - soluble in what solution?

NH4OH

25. Ionic strenghth of 0.1 M   NaCl solution

0.1

26. Ionic strenghth of 0.2 M  AICI3  

1.2

27. Ionic strenghth of 0.2 M MgCl2

0.6

28. Ionic strenghth of 0.2 M MgSO4

0.8

29. Ionic strenghth of 0.1 M AICl3

0.6

30. Ionic strenghth of 0.2 M NaCl

0.2

31. Hydrolisis degree

h= N(hydrolised ions)/N(general ions) *100%

32. activity:

a=fc

33. group reagent is

The reagent which is employed in identifying a group of cations is known as a group reagent

34. Name the cations of the second group

Ag+, Hg2+, Pb2+

35. Name the cations of the third group

Ca2+, Sr2+, Ba2+

36.  The law of action of the masses, which meaus that

the rate of a chemical reaction is directly proportional to the product of the molar concentrations of the reactants raised to the power of stoichiometric coefficients

37. The equilibrium constant shows

how many times the rate of the forward reaction is greater than the rate of the reverse reaction (at a given temperature and concentration)

38. If K=1, to

the rates of forward and backward reactions are equal.

39. If K>1 to

the opposite reaction prevails, the balance is shifted to the left

40. Electrolytes are substances

solutions or melts of which conduct an electric current (have ionic conductivity)

41. degree of disaociation electrolyte (a) –

the ratio of the number of molecules decayed into ions to the total number of dissolved electrolyte molecules

42. Acids are

electrolytes that, upon dissociation in aqueous solutions, only remove hydrogen ions as cations

43. lonic strength of solution

it is equal to the half-sum of the products of the molar concentrations (Ci) of each ion by the square of its charge (Zi)

44. Neutral environment

[H+] = [OH-] = 10-7 M

45. PH value -

this is the negative logarithm of the concentration of hydrogen ions

46. Buffer systems

a set of several substances in a solution that impart buffer properties to it, i.e. the ability to withstand a change in the active reaction of the medium (pH) when diluting, concentrating a solution or adding small amounts of a strong acid or alkali to it

47. Founder of the theory of electrolytic dissociation

S. Arrhenius

48. Hydrolysis is-

interaction of salt ions with water, as a result of which week electrolytes are formed

49. The degree of  hydrolysis is

ratio of the number of hydrolyzed salt molecules to the total number of dissolved molecules

50. The degree of hydrolysis is

ratio of the number of hydrolyzed salt molecules to the total number of dissolved molecules

51. Group reagent of the second group  

HCl

52. Group reagent of the third group

H2SO4

53. Group reagent of the first group

No

54. Group reagent of the fourth group

NaOH (in excess)

55. Analytical chemistry is called

the science of methods for determining the qualitative and quantitative composition of substances and their mixtures by the intensity of the analytical signal

56. A high-quality chemical analysis is

detection of chemical elements, ions, atoms, functional groups, and molecules in the analyzed substance

57. Quantitative chemical analysis is

determination of the quantitative composition of the substance