FINAL_TESTS_2010

15. To write reaction of Co³⁺ Chloride and excess of ammonia thiocyanate in molecular form (coordinative number of Co³⁺ is 6) and to calculate the sum of coefficients in this reaction (remember, that absence of coefficient before formula means figure 1):

__________ + ___ ____________ → _____________________ + __ ______________

Sum of coefficients: ______

16. Calculate gravimetric factor f for determination of Ca²⁺ content in CaCl₂·6H₂O (M=219,08 g/mol) in the form of precipitate Ca₂P₂O₇ (M=254,10 g/mol):

1	1,7380;	Answer:___________________
2	0,8622;
3	1,1599;
4	0,5799.

17. What is dentation of Tetrasodium EDTA:

1	Mono dental;	Answer:___________________
2	Bi dental;
3	Tri dental;
4	Tetra dental.

18. Calculate mass of H₃PO₄ (M=98,00 g/mol), dissolved in 500 mL of solution, if for titration of 10 mL of this acid it was used 10 mL of 0,01 N NaOH):

Solution: _________________________________________________________________________

_________________________________________________________________________________

Answer:_________________

19. Calculate solubility (in g/L) of Fe(OH)₃ at pH=4 (SP=4·10^-38; M=98,22 g/mol)

Solution: _________________________________________________________________________

_________________________________________________________________________________

Answer:_________________

20. Write the formula of relationship between normality (N) and molarity (M) of solution.

Answer:_________________

21. Determine the correspondence between titration system and the best indicator:

	Titration system		Indicator	Answer: A-____________; B-____________; C-____________.
A. B. C.	0,1 N hydrochloric acid HCl by 0,1 N Sodium hydroxide NaOH (pHeq=7,00) 0,1 N acetic acid CH3COOH by 0,1 N Sodium hydroxide NaOH (pHeq=8,87) 0,1 N hydrochloric acid HCl by 0,1 N Ammonium hydroxide NH4OH (pHeq=5,73)	1 2 3 4 5 6 7 8	Alizarin yellow R (pT=11,3) Thymol Blue (pT=1,7) Phenol red (pT=5,8) Bromophenol blue (pT=4,1) Litmus neutral (pT= 7,1) Thymol blue (pT=8,9) Cresol red (pT=8,2) Phenolphthalein (pT=9,6)

22. Calculate pH of 0,01 N NaH₂PO₄ (pK₁=1,96; pK₂=6,70; pK₃=12,44).

1	1,96	Answer: _________________
2	5,31
3	12,92
4	7,92

23. It is necessary for preparation of coarse-crystalline sediment:

1	To precipitate of hot concentrated solutions;	Answer:_____________
2	To precipitate of cold diluted solutions;
3	To precipitate of hot diluted solutions;
4	To precipitate of cold concentrated solutions.

24. Calculate pH of buffer solution, contained 0,1 mol NH₃ and 0,01 mol NH₄Cl in 1 L (pK (NH₃)=9,24).

Solution: _________________________________________________________________________ _________________________________________________________________________________ Answer:_________________

25. Calculate Redox potential of solution, contained 0,01 N КMnO₄ and 0,001 N MnSO₄ per 1 L at рН=3 (E_o = + 1,51 V).

Solution: _________________________________________________________________________ _________________________________________________________________________________ Answer:_________________

26. Calculate dissociation degree α of 0,1 N H₃BO₃ (K _{1 dis}=5,810^-10)

Solution:___________________________________________________

Answer:__ α =______

27. Equivalent mass of Ce³⁺ (A=140,12 g/mol) cation in reaction with Trilon B is:

1	140,12 g-eq/g;	Answer:_____________
2	70,06 g-eq/g;
3	46,71 g-eq/g;
4	16,75 g-eq/g;
5	53,96 g-eq/g.

28. Note functional groups in the formula of Trilon B

_________-	C H2		CH2	- COONa
		N-CH2-CH2-N
NaCOO-	C H2		CH2	- _________

29. Calculate concentration of solution, contained 0,008 g of solute in 1000 g of solution.

1	8 ppm;	Answer:_____________
2	800 ppm;
3	0,8 ppm;
4	80 ppm;
5	0,008 ppm.

30. Write formulas of temporary hardness salts – cause of scale formation

Cause of scale?

Answer: Formulas of dissolved salts in fresh water:________________________