Themes for home preparation

The characteristics of d-elements of VIII group.

Iron. The structure of atom, oxidation states. Occurrence in nature. Obtaining of cast iron and steel. Physical and chemical properties of iron. Oxide, hydroxide and salts of iron (II): obtaining and properties. Reducing properties of iron (II).

Oxide, hydroxide and salts of iron (III): obtaining and properties. Complexes of iron.

Compounds of iron (VI): ferrates, their properties.

Cobalt, nickel. The structure of atoms, oxidation states. Obtaining of cobalt and nickel, their properties. Oxides, hydroxides, salts of cobalt (II) and nickel (II), their obtaining and properties. Oxide of cobalt (III), hydroxides of cobalt (III) and nickel (III), their obtaining, interaction with acids. Complexes of cobalt and nickel.

Application of iron, cobalt, nickel and their compounds. Comparation of properties of iron, cobalt, nickel and of their compounds.

Questions and tasks

Iron, cobalt, nickel

Questions and tasks

1. What chemical processes occur when obtaining cast iron?

2. What is the essence of convertor and Martin processes of steel obtaining? What chemical processes these methods are based on?

3. Why does the stability of compounds with an oxidation state of + 2 increase, and of those with an oxidation state of + 3 decrease in a range Fe - Co - Ni?

4. Write the equations of the chemical reactions, which proceed when iron corrodes.

5. How do iron, cobalt and nickel react with sulfuric and nitric acids?

6. By what reactions is it possible to obtain oxides and hydroxides of iron (II), cobalt (II) and nickel (II)? Describe their acid-base properties.

7. Compare the composition and stability of ammonia and cyanide complexes of iron (II), cobalt (II) and nickel (II). 8. By what reactions is it possible to obtain oxides and hydroxides of iron (IІI), cobalt (ІII) and nickel (ІII)? Describe their acid-base properties.

9. What volume of chlorine at the temperature of 0° and at the pressure of 101,3 kPa is necessary to oxidise 1 ton of 24% potassium hexacyanoferrate (II) solution?

10. What oxidation state is the most stable in ordinary compounds and in complexes: а) of iron, b) of cobalt with strong field ligands?

11. Why is iron (ІІІ) iodide not obtained? Give the equation of the chemical reaction, which will proceed when mixing the relevant solutions.

12. How is potassium ferrate obtained? How does it react with sulfuric acid? Give the equations of the relevant reactions Quiz problems

1. Cast iron production in a blast furnace requires 180 t of lime on every 1000 t of ore. In this case 350 t of slag is obtained. The mass fraction of admixtures in ore is:

А. 10 %

B. 14 %

C. 19 %

D. 25 %

Е. 35 %

4. A solution of substance X has green color. The green amorphous precipitate which gradually changes colour to brown is formed after potassium hydroxide addition at atmospheric conditions. The white crystalline precipitate is obtained after addition of silver nitrate to a solution of substance of X. The substance X is:

А. Fe(NO₃)₂

В. FeSO₄

С. FеСl₂

D. Fe₂(SO₄)₃

Е. FеСl₃

8. Gas evolving from a blast furnace contains 32 % CO, 14 % СО₂ and 54 % N₂. How many cubic metres of air are necessary for combustion of 1 m³ this gas:

А. 0,16 m³

B. 0,32 m³

C. 0,8 m³

D. 1,24 m³

Е. 1,6 m³

5. At addition of hexacyanoferrate of (ІІ) potassium to a solution of substance X the dark blue precipitate is obtained, and at addition to a solution of the same substance of X barium chloride the white crystal precipitation is obtained. The substance X is:

А. Fe(NO₃)₂

В. FeSO₄

С. FeCl₂

D. Fe₂(SO₄)₃

Е. FеСl₃

2. 8 g iron were immersed in a vessel which contained 60 g 10 %-s' solution of hydrochloric acid and the vessel have left to stand on air. Next day it was found out, that the following substance was formed in the vessel :