The solution of the control work No.1 of variant 01 of the collection on chemistry Shimanovich I.E.

Tasks:

1. Determine the equivalent and equivalent mass of phosphorus, oxygen and bromine in compounds
РН3, H2О, НВr.

21. Write electronic formulas of atoms of elements with serial numbers 9 and 28. Show the distribution of electrons of these atoms in quantum cells. To which electronic family does each of these elements belong?

41. On the basis of the position of germanium and technetium in the periodic system, formulate the formulas of meta, orthogermanic acids and technetium oxide corresponding to their highest degree of oxidation. Draw the formulas of these compounds graphically.

61. What chemical bond is called covalent? How can the direction of the covalent bond be explained? How does the valence bond (BC) method explain the structure of the water molecule?

81. Calculate how much heat is released when Fe2O3 is reduced with metallic aluminum, if 335.1 g of iron were obtained.

101. Calculate Go298 for the following reactions:
A) 2NaF (k) + Cl2 (g) = 2NaCl (k) + F2 (g)
B) PbO2 (k) + 2Zn (k) = Pb (k) + 2ZnO (k)
Is it possible to obtain fluorine by reaction (a) and recover PbO2 by zinc by reaction (b)?

121. Oxidation of sulfur and its dioxide proceeds according to the equations:
A) S (k) + O2 = SO2 (k);
B) 2 SO2 (g) + O2 = 2 SO3 (g)
How will the rates of these reactions change if the volumes of each system are reduced fourfold?

141. Calculate the molar and equivalent concentration of a 20% solution of calcium chloride with a density of 1.178 g / cm3

161. A solution containing 0.512 g of non-electrolyte in 100 g of benzene crystallizes at 5.296 ° C. The crystallization temperature of benzene is 5.5 ° C. The cryoscopic constant is 5.1 °. Calculate the molar mass of the solute.

181. Make molecular and ion-molecular equations of interaction reactions in solutions between:
A) NaHCO3 and NaOH;
B) K2SiO3 and HCl;
C) BaCl2 and Na2SO4.

201. Make up the ion-molecular and molecular equations of joint hydrolysis occurring when mixing solutions of K2S and CrCl3. Each of the salts taken is hydrolyzed irreversibly to the end with the formation of the corresponding base and acid.