Solution of the variant 51 KR 1 - chemisty Shimanovich

The decision of the test No. 1 of option 51 of the collection of chemistry Shimanovich I.E.
(formatted in Microsoft Word)

Tasks:

12. Write the equations for the reactions of Fe (OH) 3 with hydrochloric (hydrochloric) acid, in which the following iron compounds are formed:
a) dihydroxiron chloride;
b) hydroxy-iron dichloride;
c) iron trichloride.
Calculate the equivalent and equivalent mass of Fe (OH) 3 in each of these reactions.

34. How many and what values ​​can the magnetic quantum number m1 take with the orbital number l = 0, 1, 2 and 3? What elements in the periodic table are called s-, p-, d- and f-elements? Give examples.

56. Chromium forms compounds in which it exhibits oxidation states +2, +3, +6. Draw up the formulas of its oxides and hydroxides corresponding to these oxidation states. Write the reaction equations proving the amphotericity of chromium (III) hydroxide.

78. Draw the energy diagram of the formation of the O2 molecule by the method of molecular orbitals (MO). How does the MO method explain the paramagnetic properties of an oxygen molecule?

99. The combustion of 1 liter of acetylene (NU) releases 56.053 kJ of heat. Write down the thermochemical equation for the reaction that produces water vapor and carbon dioxide. Calculate the heat of formation of C2H2 (g). Answer: 226.75 kJ / mol.

120. Calculate the change in entropy for reactions proceeding according to the equations:
2CH4 (g) = C2H2 (g) + 3H2 (g)
N2 (g) + 3H2 (g) = 2NH3 (g)
C (graphite) + O2 (g) = CO2 (g)
Why in these reactions Sо298> 0; <0; ~ 0?
Answer: 220.21 J / K; -198.26 J / K; 2.93 J / K.

122. Write an expression for the equilibrium constant of the homogeneous system N2 + 3H2 2NH3. How will the rate of the direct reaction - the formation of ammonia - change if the hydrogen concentration is tripled?

158. Mixed 247 g of 62% and 145 g of 18% sulfuric acid solution. What is the percentage of the resulting solution? Answer: 45.72%.

180. Calculate the percentage concentration of an aqueous solution of methanol CH3OH, the crystallization temperature of which is -2.79 ° C. The cryoscopic constant of water is 1.86 °. Answer: 4.58%.

200. Which of the substances: NaCl, NiSO4, Be (OH) 2, KHCO3 - interacts with sodium hydroxide solution. Write down the molecular and ion-molecular equations of these reactions.

211. Which of the salts RbCl, Cr2 (SO4) 3, Ni (NO3) 2, Na2SO3 are hydrolyzed? Draw up the ionic-molecular and molecular equations for the hydrolysis of the corresponding salts. What is the pH value (> 7 <) have solutions of these salts?