The solution of the test No. 1 of option 66 of the collection of chemistry Shimanovich I.E
(formatted in Microsoft Word)

Tasks:

8. Calculate the equivalent and equivalent mass of H3PO4 in the formation reactions:
a) hydrogen phosphate;
b) dihydrogen phosphate;
c) orthophosphate.

30. Write the electronic formulas of the atoms of the elements with serial numbers 14 and 40. How many free d-orbitals do the atoms of the last element have?

48. Manganese forms compounds in which it exhibits the oxidation state 2, 3, 4, 6, 7. Make up the formulas of its oxides and hydroxides corresponding to these oxidation states. Write the reaction equations proving the amphotericity of manganese (IV) hydroxide

70. How does the method of valence bonds (ВС) explain the angular structure of H2S molecules and linear CO2 molecules?

95. The reaction of benzene combustion is expressed by the thermochemical equation:
C6H6 (l) 7 1/2 O2 (g) = 6CO2 (g) 3H2O (g); H =?
Calculate the thermal effect of this reaction if it is known that the molar heat of vaporization of benzene is 33.9 kJ.
Answer: -3135.58 kJ.

111. On the basis of the standard heats of formation and the absolute standard entropy of the corresponding substances, calculate the Gо298 reaction proceeding according to the equation:
4NH3 (g) 5O2 (g) = 4NO (g) 6H2O (g)
Is this reaction possible under standard conditions?
Answer: -957.77 kJ.

136. The equilibrium constant of the homogeneous system CO (g) H2O (g) CO2 H2 (g) at a certain temperature is 1. Calculate the equilibrium concentrations of all reactants if the initial concentrations: [CO] ref = 0.10 mol / l; [H2O] ref = 0.40 mol / l.
Answer: [CO2] p = [H2] p = 0.08 mol / l; [CO] p = 0.02 may / l; [H2O] p = 0.32 mol / L.

153. What volume is 0.3 N. acid solution is required to neutralize a solution containing 0.32 g of NaOH in 40 cm3? Answer: 26.6 cm3.

174. How many grams of urea (NN2) 2CO should be dissolved in 75 g of water to lower the crystallization temperature by 0.465 °? The cryoscopic constant of water is 1.86 °. Answer: 1.12 g.

196. Make molecular equations of reactions, which are expressed by ionic-molecular equations:
a) Zn2 H2S = ZnS 2H
b) HCO-3 H = H2O CO2
c) Аg Сl- = AgCl

206. What is the value of pH (> 7 <) have solutions of salts Na2S, A1Cl3, NiSO4? Make up the ionic-molecular and molecular equations for the hydrolysis of these salts.