1. Chemical Reaction

2. fertilizers and artificial filters Chemical reactions have a great importance in our life

3. Chemical Reaction It is the breaking up of coherence in some molecules of the reactants and the formation of new coherence in the molecules of the new resultants from the reaction.

4. Are all chemical reactions the same?

5. Thermal decomposition reactions

6. The compound is broken up by heat. It breaks up into simple substances. It may break up completely into its simple elements or a simpler compound than the original one.

7. Red mercury oxide decomposes by heat into mercury (silver) which precipitates at the bottom of the tube and oxygen rises at the top of the tube. This causes the increase in the flame of the match stick. Some metals oxides decompose by heat into metal and oxygen.

8. Blue copper hydroxide decomposes by heat to copper oxide (black) and water vapor. Some metals hydroxides decompose when heated into metal oxide and water. Black

9. Green copper carbonate decomposes by heat to black copper oxide and carbon dioxide. Most metal carbonates decompose by heat to metal oxide and carbon dioxide. Green Black

10. Blue copper Sulphate decomposes by heat to black copper oxide and sulfur trioxide. Most sulfate metals decompose when heated to metal oxide and sulfur trioxide Blue

11. White sodium nitrates decompose by heat into yellowish white sodium nitrates and oxygen. All metal nitrates decompose by heat and oxygen gas rises white Yellow

12. Substitution reactions Substitution reactions occur when there is an active metal “more effective” that replaces another less active metal “less effective” in another compound This can be done using the series of chemical activity.

13. The series of chemical activity is the arrangement of the metals in a descending order according to the degree of its chemical activity.

14. The element which is more active substitutes the less active one. All elements above hydrogen in the series replace hydrogen in acid solutions,

15. whereas the elements that follow hydrogen do not replace hydrogen in acids except under certain conditions.

16. Substitution reactions are classified into two types Simple substitution reactions Double substitution reaction Click to go

17. Simple substitution reactions

18. They are reactions where an element replaces another one. Note that the substituting element is more active than the substituted one.

19. A Metal substitutes water hydrogen or acid The substitution of a metal instead of another one into its salt

20. A Metal substitutes water hydrogen or acid Metals substitute water hydrogen and produce metal hydroxide and hydrogen rises. Metals react with water as they substitute acid hydrogen and produce salt and hydrogen rises The reaction of water with sodium

21. Metals reaction with acid hydrogen On adding hydrochloric acid, it does not react with copper whereas it reacts with zinc immediately composing salt and hydrogen.

22. Metals reaction with acid hydrogen After a short time, zinc completely reacted and aluminium started to react more strongly than the zinc reaction composing salt and hydrogen. As for copper, it does not react.

23. The substitution of a metal instead of another one into its salt Some metals replace another metal in its salt solution that follows it in the series of chemical activity. magnesium sulfate

24. Double substitution reaction It is a reaction where double substitution occurs between the ions of two compounds to form two new compounds Each element replaces the other to form two compounds different from reactants

25. Double substitution reactions are classified into Reaction between acid and Alkali. (neutral) On heating the solution, water evaporates and sodium chloride remains

26. The reaction of acid with salt Acids react with salt. The resultant depends on the type of acid and salt. The reaction of hydrochloric acid with sodium carbonate Hydrochloric acid reacts with sodium carbonate forming sodium chloride, water and carbon dioxide which turbid lime water.

27. The Reaction of salt with salt Double substitution reactions between salt solutions are accompanied by the formation of a precipitate silver nitrate sodium chloride white precipitate silver chloride sodium nitrate

28. Oxidization and Reduction When hydrogen passes through hot copper oxide, hydrogen takes the oxygen away from copper oxide and water is formed. Copper oxide turns into copper During this reaction, the hydrogen is oxidized because it got united with oxygen. On the other hand, copper oxide was reduced because oxygen is taken away from it.

29. We can say that copper oxide is an: oxidizing factor because it oxidized hydrogen. But hydrogen is a: reducing factor because it reduced copper oxide to copper

30. Oxidization A chemical process which causes the increase of the oxygen percentage and the decrease of hydrogen Reduction A chemical reaction which causes the decrease of oxygen percentage or the increase of hydrogen

31. Oxidizing factor Reducing agent It is the substance which gives oxygen or takes away hydrogen during a chemical reaction It is the substance which takes away oxygen or gives hydrogen during a chemical reaction

32. There are chemical reactions which contain oxidization and reduction although they have neither oxygen nor hydrogen The reaction of sodium with chlorine includes both oxidation and reduction processes. This reaction gives sodium chloride which is known as table salt

34. Notice that in the reaction the sodium atom turns into sodium ion, whereas chlorine atom turns into chloride ion. The sodium atom lost one electron and turned from a neutral atom to positive ion+1. This process is called oxidization. Ions can not remain free, so they move to chlorine atom (gaining electrons). It turn into neutral chloride ions -1. This process is called reduction.

35. Oxidization Reduction A chemical process where the atom loses an electron or more. A chemical process where an atom gains one or more electron

36. Oxidizing factor Reducing agent It is the substance which gains an electron or more during a chemical reaction It is the substance which loses one or more electrons in a chemical reaction

37. Notice that the two processes of oxidization and reduction are concurrent processes.