Last lesson 2g) Hydrogen

acid + metal salt + hydrogen

Hydrochloric acid + magnesium magnesium chloride + hydrogen

Nitric acid + iron iron nitrate + hydrogen

Sulphuric acid + zinc zinc sulphate + hydrogen

In general, hydrochloric acid makes a chloride, nitric acid makes a nitrate, and sulphuric acid makes a sulphate.

“salts”

Preparation of hydrogen

Combustion of hydrogen

2H2 + O2 2H2O

Test for water

Cobalt chloride paper turns from blue to pink

Pure water?

Boils at 100°C

Hydrogen and chlorine

H2(g) + Cl2(g) 2HCl(g)

Hydrogen chloride gas (covalent) dissolves in water to from hydrochloric acid (H+ + Cl-)

Today’s lesson h) The transition metals - iron and copper

A treasure hunt!

1.

• Iron + steam iron(III) oxide + hydrogen.

• 2Fe(s) + 3H2O(g) Fe2O3(s) + 3H2(g)

2.

• Iron wool heated to glowing red reacts vigorously with chlorine gas in a flask. The product is red-brown solid iron(III) chloride

2Fe + 3Cl2 2FeCl3

3.

• Iron ions in solution will react with hydroxide ions to form iron hydroxides which are insoluble and very coloured

• Fe2+(aq) + 2OH-

(aq) Fe(OH)2(s) (“dirty green”)

• Fe 3+(aq) + 3OH-

(aq) Fe(OH)3(s) (“rusty brown”)

4.

Copper will dissolve in concentrated nitric acid to form copper nitrate and brown nitrogen dioxide gas

Cu(s) + 4HNO3(aq) Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)

5.

• copper(II) oxide is a base (does not dissolve in water)

• copper hydroxide is pale blue and is formed

when sodium hydroxide is added to a copper salt. It us used as a test for copper.

6.

• Anhydrous copper sulphate is white and hydrated copper sulphate is blue (reversible)

• Copper carbonate decomposes at high temperatures to form copper oxide and carbon dioxide.

• CuCO3 (s) → CuO (s) + CO2 (g)

7.

• Copper chloride is light green• There are copper(I) compounds such as

copper(I) oxide

8.

• •copper(II) ions react with ammonia to form the following complex ion

• (copy carefully!)

• [Cu(H2O)2(NH3)4]2+

9.

• Copper and iron are typical transition metals• Variable valency (ions with different charges)• Coloured compounds• Metals and their compounds make good

catalysts• Properties of variable valency• Typical metals (high m.p., dense, conduct,

ductile, malleable etc.)