Themes for home preparation

Structure of atom, valence, oxidation state. Occurence in nature, obtaining. Physical and chemical properties.

Hydrogen sulphide, obtaining, structure of molecule. Acid-base properties. Sulphides, classification by solubility, hydrolysis. Reducing properties of hydrogen sulphide and sulphides.

Polysulphides, obtaining, structure and properties.

Sulfur (IV) oxide obtaining and properties. A sulfurous acid, its stability, acid-base properties, sulphites. Oxidation-reduction properties of sulfur (IV) oxide Hydrosulfurous acid and pyrosulfurous (disulfurous) acid, their salts.

Sulfur (VI) oxide obtainings and properties. Action of concentrated and diluted sulfuric acid on metals. Obtaining of sulfuric acid and its properties. Sulphates. Disulfuric (polysulfuric) acid, its properties. Peroxyacids of sulfur (peroxymonosulfuric and peroxydisulfuric), their obtaining, structure of molecules, properties.

Sodium thiosulphate, its obtaining, structure, properties. Polythionic acids, their salts.

Oxychlorides of sulfur (thionyl chloride, sulfuryl chloride), chlorosulphonic acid. Obtaining, structure of molecules, properties. Compounds with halogens.

Questions and tasks

1. What oxidation states are characteristic for chalkogenes in their compounds? Why do chalkogenes can show a maximum valency of 6, and oxygen is only 2?

2. What are the peculiarities of free sulfur structure? What molecules does solid, liquid and gaseous sulfur consist of? How does their composition depend on temperature?

3. How does sulfur react with water, acids and alkalies? Give the equations of the relevant reactions.

4. Give examples of reactions, in which sulfur acts as an oxidising agent, reducing agent, or participete in autoxidation - autoreduction.

5. Explain, using the concept of hybridization, how and why do the angles between bonds in molecules H₂O (104,5°), H₂S (92°), H₂Se (91°), H₂Te (89,5 °) change.

6. Analyze conditions of metals sulphides formation by double replacement reactions with H₂S. Is it possible to receive in this way sulphides of a) Fe; b) Cd; c) Mn; d) Pb? What is the key difference of sulphides obtaining by double replacement reactions with H₂S and Na₂S?

7. How and why does the hydrolysis of sulphides proceeds? Is it possible to obtain sulphides Al₂S₃ and Cr₂S₃ by double replacement reactions in water solution? How and why do the products form?

8. What are polysulphides and sulphanes? How can they be received? Give the structure formula of H₂S₅ and indicate the oxidation states of sulfur in this compound.

9. How can sulfurous gas be received in industry and in laboratory? Where is sulfurous gas used?

10. What volumes of H₂S and SO₂ should react at standard conditions, to form 100 kgs of sulfur?

11. How is sulfuric acid received in industry? Why is free anhydride absorbed by sulfuric acid, not by water at its production? Are new compounds formed?

12. How does sulfuric acid react with metals and non-metals? Give the equations of the reactions of diluted and concentrated sulfuric acid interaction with magnesium, iron, copper, sulfur and carbon.

13. What reactions proceed at heating of hydrosulphite and hydrosulphate of sodium? Give the structural formulas of acids, which correspond to products of the reactions.

14. How are peroxydisulfuric and peroxymonosulfuric acid received? Give their structural formulas; indicate oxidation states of sulfur and oxygen.

15. What is the peculiarity of thiosulphate ion? Describe its oxidation-reduction properties. Give the equations of the relevant reactions.

16. What are polythionic acids? What composition and structure do they have? What oxidation states do atoms of sulfur have in these compounds? How is the tetrathionate of sodium received?

17. What compounds of sulfur with chlorine exist? What chemical properties do they have, how do they react with water, alkalis?

Дата добавления: 2015-11-14