The decision of the test No. 1 of option 69 of the collection of chemistry Shimanovich I.E.
(formatted in Microsoft Word)

Tasks:

11. From 3.31 g of metal nitrate, 2.78 g of its chloride is obtained, calculate the equivalent mass of this metal. Answer: 103.6 g / mol

33. Write the electronic formulas of atoms of elements with serial numbers 21 and 23. How many free d-orbitals are in the atoms of these elements?

51. Which of the p-elements of the fifth group of the periodic system - phosphorus or antimony - has more pronounced non-metallic properties? Which of the hydrogen compounds of these elements is the strongest reducing agent? Motivate your answer with the atomic structure of these elements.

73. What chemical bond is called ionic? What is the mechanism of its formation? What properties of an ionic bond distinguish it from a covalent bond? Give two examples of typical ionic compounds. Write down the equations for the transformation of the corresponding ions into neutral atoms.

98. The interaction of 6.3 g of iron with sulfur released 11.31 kJ of heat. Calculate the heat of formation of iron sulfide FeS. Answer: -100.26 kJ / mol.

114. Which of the carbonates: BeCO3 or BaCO3 - can be obtained by the reaction of the interaction of the corresponding oxides with CO2? What is the most vigorous reaction? Draw a conclusion by calculating Gо298 reactions. Answer: +31.24 kJ; -130.17 kJ; -216.02 kJ.

139. Why does the equilibrium of the N2 + 3H2 2NH3 system shift when the pressure changes and the equilibrium of the N2 + O2 2NO system does not shift? Motivate your answer on the basis of calculating the speed of forward and reverse reactions in these systems before and after the pressure change. Write expressions for the equilibrium constants of each of these systems.

156. What mass of NaNO3 should be dissolved in 400 g of water to prepare a 20% solution? Answer: 100 g.

177. How many grams of urea (NH2) 2CO should be dissolved in 250 g of water to raise the boiling point by 0.26 °? Ebullioscopic water constant 0.52 °. Answer: 7.5 g

199. Make molecular equations of reactions, which are expressed by ionic-molecular equations:
a) Be (OH) 2 + 2OH- = BeO22- + 2H2O
b) CH3COO- + H + = CH3COOH
c) Ba2 + + SO2-4 = BaSO4

209. What is the pH value (> 7 <) have solutions of Na3PO4, K2S, CuSO4 salts? Make up the ionic-molecular and molecular equations for the hydrolysis of these salts.