CHEMICAL EQUATIONS & REACTIONS
TOPIC – 1
(CHEMICAL REACTION)
CHEMICAL REACTION:  Process in which reactants combine to form products.
SIGNS OF OCCURING OF REACTION:
a) Gases may be released
b) Precipitate may be formed
c) Heat may be released or absorbed
d) Colour change may occur
e) Change in state
SKELETAL REACTION: Reaction which is not balanced is called skeletal reaction.
BALANCED CHEMICAL REACTION: The reaction in which number of atoms of each element remains same before and after chemical reaction.
Note:  Chemical reaction is balanced to obey “Law of conservation of mass”.
RULES TO FOLLOW WHILE BALANCING REACTION:
     1) Balance O2 and H2 at last.
     2) First balance all elements other than O2 and H2.
HOW TO MAKE REACTION MOR INFORMATIVE:
     1) By mentioning the states of reactants and products.
     2) By showing the temperature released or absorbed by delta sign
         (Exothermic = +∆, endothermic = -∆).
     3) By showing arrow signs ( irreversible →, reversible ↔).
QUESTIONS
BALANCE THE FOLLOWING REACTIONS:
1. Fe  +  H2O          ----------------   Fe3O4  +  H2
2. P4    +  O2         ---------- -------   P2O5
3. Mg   +  N2           ----------------  Mg3N2
4. C5H12   +  O2       ----------------  CO2  +  H2O
5. Ca(OH)2  +  H3PO4 ------------- Ca3(PO4)2  + H2O
6. Al  + O2          --------------------  Al2O3
7. S8  +  F2      -----------------------  SF6
8. FeSO4         ----------------------- Fe2O3  +  SO2  +  SO3
9. Pb(NO3)2     ---------------------- PbO  +  NO2  +  O2
10. MnO2  +  HCl  ------------ MnCl2  +  H2O  +  Cl2
11. Xe  +  F2           ------------ XeF6
12. N2  +  H2