Chemical properties of hydrogen

2.1. Put 1 granule of zinc into a test tube and add 2-3 mls of diluted hydrochloric acid. Collect evolved gas into other test tube with the method of water replacement then bring the test tube with the gas to a flame of a burner. What is observed? What role does hydrogen play into the first and the second reactions?

2.2. Put 1 granule of aluminium into a test tube and add 2-3 mls of diluted sodium hydroxide solution. Collect evolved gas into other test tube with a water replacement method, then bring a test tube with the collected gas to a flame of the burner. What is observed? What role does hydrogen play in these reactions?

2.3. Put approximately 1-2 microspatulas of copper (II) oxide into a test tube then clamp it upside down in a stand with a small declination. Heat the test tube with the help of a burner and pass hydrogen from a Kipp gas generator into the test tube. What can you observe? What role does hydrogen play in this experiment?

2.4. Place 2-3 mls of diluted sulfuric acid into each of two test tubes and add 2-3 drops of 0,1N potassium permanganate solution. Pass hydrogen from a Kipp gas generator into the first test tube, and place granule of zinc into the other. What can you observe? Where does the colour disappear faster? Why?

Chemical properties of oxygen

3.1. Put few crystals of potassium permanganate into a test tube. Heat the test tube at a burner. What gas evolves? How it can be proved?

3.2. Put 1-2 microspatulas of potassium chlorate into a test tube. Heat the test tube with the help of a burner until the salt melts. Check up whether the oxygen is evolving. Add some manganese (IV) oxide into the test tube. What will you observe? What is the role of MnO₂?

3.3. Collect oxygen by water replacement method in a 100 mls flask so that approximately 10 mls of water remained in it. Then upturn a flask and enclose it with glass. Bring the fire to sulfur in the iron spoon and put it into a flask. Compare the burning of sulfur in air and in oxygen. Stir up a flask after sulfur burnt and add 1-2 drops of a neutral litmus solution to a solution obtained. What can you observe? Make a conclusion about properties of oxide received.

3.4. Put 1 ml of a hydrogen peroxide solution to a test tube and add 1-2 crystals of manganese dioxide. What gas evolves? How it can be proved? What is the role of manganese dioxide?

3.5. Put 4-5 drops of 0,1N solutions of potassium iodide and sulfuric acid into a test tube and add 4-5 drops of hydrogen peroxide solution. What can you observe? What properties does hydrogen peroxide manifest in this reaction?

3.6. Put 4-5 drops of 0,1N solutions of potassium permanganate and sulfuric acid into a test tube and add 4-5 drops of hydrogen peroxide solution. What can you observe? What properties does hydrogen peroxide show in this reaction?

Laboratory work 3

S-ELEMENTS OF THE FIRST GROUP

Themes for home preparation

Structure of atoms, oxidation state. Occurrence in nature, obtaining, properties. Activity of interaction of alkali metals with water, hydrogen and oxygen, other nonmetals. Change of reactivity in the lithium - cesium range. Peculiarities of lithium properties.

Oxides, peroxides, superoxides, ozonides of alkali metals. Their obtaining, structure, properties. Hydroxides, their obtaining, properties and application. The most important salts. Manufacturing of soda and potash.

Questions and tasks

1. What electronic structure have the atoms of s-elements of II group?

2. Why does the reactivity in the range Li - Na - K – Rb - Cs change? Give the equations of the relevant reactions.

3. What is the difference of chemical properties of lithium and other alkali metals? What is the reason of this difference?

4.What are the methods of alkali metals obtaining in industry?

5. How can oxides of alkali metals be obtained? Is it possible to obtain them by direct interaction of metals with oxygen? Give the equations of the relevant reactions.

6. How do alkali metals react with water, hydrogen, nitrogen, and carbon? What substances are formed? How do they react with water?

7. How can hydroxides of alkali metals be obtained? What properties have these compounds?

8. How do ozonides of alkali metals be obtained? Is it possible to obtain such compounds for all alkali metals? Make up the equations o f the reactionss of obtaining of potassium ozonide and its interaction with carbonic gas.

9. What compounds are called calcined soda (washing soda), baking soda and crystalline soda? Where are they applied?

10. How is soda obtained in industry? Give the equations of the relevant reactions.