CHEMICAL REACTIONS AND EQUATIONS-1.pdf

It is very useful for class 10th students, CBSE/ STATE BOARDS .

1. SYLLABUS OF CHEMISTRY (SCIENCE)
CBSE CLASS 10
TH
STD.
1.CHEMICAL REACTIONS AND EQUATIONS
2.ACIDS, BASES AND SALTS
3.METALS AND NON ,METALS
4.CARBON AND ITS COMPOUNDS
5.PERIODIC CLASSIFICATION OF ELEMENTS

2. By Tripurari Prajapati
M.Sc.. Biotechnology
CHAPTER-1 SCINCE (CBSE CLASS 10)

3. CONTENTS
❑ChemicalReaction
❑ChemicalEquation
➢Writinganchemicalequation
➢BalancedChemicalEquation
❑TypesofChemicalReaction
➢CombinationReaction
➢DecompositionReaction
➢DisplacementReaction
➢DoubleDisplacementReaction
➢OxidationAndReduction
❑Corrosion
❑Rancidity

4. Chemical reaction
➢Chemicalreactionisaprocessinwhichoneormore
substances(Reactants),areconvertedtooneormore
differentsubstances(Products).
➢Substancesareeitherchemicalelementsorcompounds.
2Na+2??????
2�2NaOH(aq)+??????
2(g)
(Reactants) (Products)

5. Reactants
Chemicalsubstancewhichreactor
disapearduringthechemicalreaction
Chemical Substances which are formed or
appear during the chemical reaction.
Eg:�??????��
3+���??????→����
3+�??????�??????
REACTANT PRODUCT

6. q. Give the name of reactants and products in each cases.
1.�??????��
3+ �
2 2�??????
3
2.6��
2+ 6??????
2��
6??????
12�
6+ 6�
2
3.�????????????�
4+ Fe ??????????????????�
4+ Cu
4.2??????
2+ �
2 2??????
2O
5.Zn + HCl �??????�??????
2+??????
2

7. Example of chemical reaCTIONIN EVERYDAY LIFE
➢Photosynthesis
➢Combustion
➢Respiration
➢Rusting
➢Digestion

8. photosynthesis

9. combustion

10. respiration

11. rusting

12. Digestion

13. Identification of chemical reaction
➢It can be determined by 5 factors
i.Change in state
ii.Change in color
iii.Evolution of gas
iv.Change in temperature
v.Formation of precipitate

14. Change in state
CO(g) + 2??????
2�(g) �??????
3OH(l)
C(s) + �
2(g) ��
2(g)
??????
2(g) + �
2(g) 2??????
2O(l)

15. Change in color

16. Evolution of gas

17. Change in temperature
CaO(s) + ??????
2�(l) ��(�??????)
2(s) + Heat
(Quick lime)
Mint + ??????
2�(l) Temperature decrease

18. Formation of precipitate

20. Chemical equation
➢Achemicalequationisthesymbolic
representationofachemicalreaction.
➢Achemicalequationcanbewrittenin2forms:
❖Wordequation
eg:Hydrogen+Oxygen Water
❖Symbolicrepresentation
eg:2??????
2+�
2 2??????
2�

21. Making a chemical equation more informative
➢Thephysicalstatesofthereactantsandproducts
canberepresentedbyusingsymbols.
➢Forsolid (s)
➢Forliquid (l)
➢Forgas (g)
➢Foraqueoussolutions (aq)
Eg:2Na(s)+2??????
2�(l) 2NaOH(aq)+??????
2�(g)

22. ➢Precipitate can also be represented by using an arrow
pointing downwards ( ).
Eg: ��
2??????�
4+���??????
2 ���??????+��??????�
4( )
➢Gaseous state of an evolved gas can be represented by
using an arrow pointing upward direction ( ).
Eg: Zn + HCl �??????�??????
2+ ??????
2( )

23. Types of chemical equation
1)Balancedchemicalequation
➢Itisanequationforachemicalreactioninwhichthe
numberofatomsforeachelementinthereactionand
thetotalchargearethesameforboththereactantsand
theproduct.
➢Eg:Zn+??????
2??????�
4 �????????????�
4+??????
2

24. Unbalanced chemical equation
➢Itisanequationwherethenumberofatomsforelementsand
theirtotalchargearenotequalinbothside.
➢Eg:Fe+??????
2O ????????????
3�
4+??????
2

25. WHY TO BALANCE A CHEMICAL REACTION
Law of conservation of mass:
➢Masscanneitherbecreatednordestroyedinachemicalreaction.
➢Thatis,thetotalmassoftheelementspresentintheproductof
thechemicalreactionhastobeequaltothetotalmassofthe
elementspresentinthereactants.
➢Inotherwords,thenumberofatomsofeachelementremainsthe
same,beforeandafterachemicalreaction.Hence,weneedto
balanceachemicalequation.

27. Examples of balance chemical equation

28. Examples of balance chemical equation

29. practice

30. practice

32. COMBINATION

35. COMBINATION REACTION
•A reaction in which two or more reactants combine to form
a single product, is called combination reaction.
•A + B + C ABC
•A + B AB
Eg: CaO(s) + ??????
2�(l) ��(�??????)
2(aq) + Heat
(Quick lime) (Slaked lime)

36. Examples of combination reaction
• C(s)+�
2(g) ��
2(g)
• 2??????
2(g)+�
2(g) 2??????
2�(l)
• S+�
2 ??????�
2
• �??????
3+??????�??????�??????
4�??????
• ??????�
2+�
2 ??????�
3

37. Decomposition reaction
•Areactioninwhichasinglereactantbreaksdownto
formtwoormoreproducts,isknownas
decompositionreaction.
•ABC A+B+C
•AB A+B
•Eg:����
3(s) ���??????+��
2(g)
(Limestone) (Quicklime)
Heat

38. Examples of decomposition reaction
•2??????????????????�
4(s) ????????????
2�
3(s) + ??????�
2(g) + ??????�
3(g)
(Ferrous sulphate) (Ferric oxide)
•2��(��
3)
2(s) 2PbO(s) +4��
2(g) + �
2(g)
(Lead nitrate) (Lead oxide) (Nitrogen (Oxygen)
•2AgCl(s) 2Ag(s) + Cl2(g)
Silver Grey
Heat
Heat
Dioxide)
Sunlight

39. Types of decomposition reaction
1.Thermal decomposition :
Thosereactionsusetheenergyintheformofheat
fordecompositionofthereactant.
Eg:����
3(s) ���??????+��
2(g)
(Limestone) (Quicklime)
Heat

40. 2.Electrolysis :
Thesereactioninvolvetheuseofelectricalenergy
forthedecompositionofthereactantmolecules.
Eg:2??????
2�2??????
2+�
2
2NaCl 2NaOH+??????
2+�??????
2
Electric current
Electric current

41. 3.Photolysis :
Thesereactioninvolvetheuseoflight
energyforthepurposeofdecomposition.
Eg:2NaCl 2��+�??????
2
�
3?????? �
2(??????)+�
Photons
Photons

42. Exothermic and Endothermic Reaction
ExothermicReaction:
Thereactionwhichareaccompaniedbytheevolutionofheatarecalled
ExothermicReaction.
Or
Thereactionsinwhichheatisreleasedalongwiththeformationofproducts
arecalledexothermicreactions.
Eg:�??????
4+2�
2 ��
2+2??????
2�+Heat

43. Endothermic Reaction :
Thereactionwhichoccurbytheabsorptionof
heat/energyarecalledendothermicreaction.
Eg:6��
2+12??????
2��
6??????
12�
6+6�
2+6??????
2�

45. Whenamorereactiveelementdisplacelessreactive
elementfromitscompound,itiscalleddisplacement
reaction.

46. Types of displacement reaction
1.Single displacement reaction
2.Double displacement reaction

49. Double displacement reaction
Thereactioninwhichtwodifferentionsorgroupofatomsin
differentionsorgroupofatominthereactantmoleculesare
displacedbyeachotheriscalleddoubledisplacementreaction.
Alsocalledasprecipitatereaction.
Eg:��
2??????�
4+���??????
2 ��??????�
4+2���??????

51. Reactivity Series

52. Neutralization Reaction
The reaction in which acid react with base to form Salt and water
are called neutralization reaction.
Eg: NaOH + ??????
2??????�
4 ��
2??????�
4+??????
2�

53. Oxidation reactions
•If a substance gains oxygen and looses
hydrogen then it is said to be oxidation.
Eg: 2Mg + �
2 2MgO

54. Reduction reaction
If a substance gains hydrogen and looses oxygen
then it is said to be reduction reaction.
Eg: CuO + ??????
2 Cu + ??????
2O

55. Redox reaction
When one reactant gets oxidized while the other
gets reduced during a reaction.
Eg:

56. Effects of redox reaction in everyday life
•RANCIDITY :
When fats and oils are oxidized, they become rancid and
their smell and taste change.
Prevention:
Air tight containers, refrigeration, adding antioxidents.
Eg: Butter, Cheese, Chips etc

57. 2. CORROSION :
A metal when attacked by substances around it such as
acids etc, it is said to corrode and this process is known as
corrosion.
Prevention :
By painting, grease or oil

58. THANK YOU