C5 - Chemical changes.

C5 - Chemical Changes

Metal + oxygen  =      Metal oxide

Metal + water   = Metal hydroxide + hydrogen

Metal + acid   =Metal salt  + hydrogen

• metal + hydrochloric acid = metal chloride

• metal + sulpheric acid = metal sulphate

• metal + Nitric acid = metal nitrate

• Reactions with water and acid always contain hydrogen in reactants: 
• Iron + water = iron hydroxide + hydrogen
• Iron +  hydrochloric acid = iron chloride + hydrogen

• Mr copper miss sulfate + Mr Iron = Mr Iron Miss sulfate + Mr copper

                                                                    ^

                                                       Mr Iron is much more            

                                                      reactive and attractive!                                            

e.g 

Copper sulfate + iron = iron sulfate + copper

Oxidation is loss                                                                                   Reduction is gain

• most from earths crust
• Silver, gold and platinum can be found streight from ground as they are less reactive. 
• oxides of metals below carbon in reactivity series can be reduced by carbon to give metal element.
• Metals more reactive than carbon cant be extracted from their ores using carbon, instead electrolyised using molten metal compound.

• Salt = compound formed when hydrogen in an acid replaced by metal. 
• Can be made by reacting a metal above hydrogen in the reactivity series with an acid.
• produces hydrogen gas as well as salt.
• Salt can then be crystilised by evaporating water. 
• REDOX REACTION = metal atoms loose electrons and are oxidised. Hydrogen gain electrons and are reduced.

• Indicatoer needed when solouble salt is prepared when reacting acid and alkali.
• carbonate reacts with acid to produce salt, water and carbon dioxide. 

• (g) - gas 
• (l) - liquid 
• (s)- solid
• (aq) - dissolved in water.

• Acids - produce H+ when added to water. 
• Bases - neutrelise acids
• Alkali - solouble hydroxide, produce OH- when added to water.
• less than 7 - acid 
• more than 7 - alkali 
• at 7 - neutral

• aeqeous soloutions of weak acids - higher Ph than strong acids with same concentration.
• As Ph decreases by one unit the htdrogen ion concentration increases by factor of 10. 

Concentration of H+ ions                                             pH value

0.1                                                                                    1.0

0.01                                                                                  2.0

0.001                                                                                3.0

0.0001                                                                              4.0