3. Chemical properties of silicon

3.1. Grind 0,5 g of magnesium dust and 0,8 g of silicon (IV) oxide in a mortar. Place mixtures on ceramic tile and burn with magnesium strip. After cooling transfer the product of the reaction by small portions into a beaker with diluted hydrochloric acid (1:1). What can you observe? What gas evolves? What are flashes caused by?

3.2. Place 2-3 mls of sodium silicate solution into a test tube and pass carbon (IV) oxide from Kipp gas generator. What can you observe? What acid is more strong - carbon or silicate?

3.3. Place 3-5 mls of 10% sodium silicate solution into a test tube, add by drops a solution of diluted hydrochloric acid (1:3) and stir with glass rod. What can you observe? Add 3-5 mls of sodium hydroxide solution in the test tube and heat. Does the obtained substance react with alkali solution at heating? Give the equations of the relevant reactions.

3.4. Place 1 ml of concentrated hydrochloric acid into a test tube and quickly add 3-5 drops of 10% solution of sodium silicate. What can you observe? Why does the precipitate not form in this case? Heat a solution to boiling. What can you observe?

3.5. Place 30 mls of concentrated sodium silicate solution in 100 mls beaker and add some crystals of copper (ІІ), nickel (ІІ), cobalt (ІІ) sulphates. What can you observe? Explain the phenomena that occur.

Laboratory work 12 germanium, tin, lead Themes for home preparation

Structure of atoms and oxidation states of germanium, tin and lead. Obtaining, properties and application of germanium, tin and lead. Their relation to acids and alkalis.

Compounds with hydrogen. Comparing properties of hydrogen compounds in a range carbon - lead.

Oxides, hydroxides and salts of germanium (II) tin (II) lead (II), their obtaining and properties. Reducing properties of germanium (II), tin (II), lead (II) compounds.

Oxide of germanium (IV), germanic acid, its salts. Obtaining and properties of - and - stannic acids. Oxide of lead (IV) its acid-base and oxidation-reduction properties. Red lead, structure, properties.

Compounds of germanium, tin and lead with halogens, their properties. Sulphides of germanium, tin and lead, their obtaining, properties. Thiosalts.

Comparing acid-base and oxidation-reduction properties of germanium, tin and lead compounds.

Questions and tasks

1. Give an electronic structure of atoms of carbon, silicon, germanium, tin and lead. What oxidation states are characteristic for these elements? How and why does the stability of different oxidation states in a range C - Pb change?

2. In what acids or mixtures of acids do germanium, tin and lead dissolve?

3. How do germanium, tin and lead react with alkalis? Give the equations of the relevant reactions.

4. Explain from the point of view of a zone theory the fact, that diamond is a dielectric, silicon and germanium are semiconductors, and tin and lead are metals.

5. What amount of lead can be received from 100 tons of ore containing 96 % Pb if the yield of a product is 95 % of theoretically possible?

6. How do the oxidation-reduction properties of simple substances change in the range of elements C - Pb?

7. What are - and -stannic acids? How are they received? What is the difference between them?

8. How does the hydrolysis of tin (ІІ) and lead (ІІ) chlorides proceed? How and why do the hydrolysis degrees in these compounds differ?

9. What processes proceed at discharge and charge of lead accumulators? What is the difference between accumulators and chemical power sources?

10. Describe acid-base and oxidation-reduction properties of lead (IV) oxide.