The need of balancing the chemical equation.
The law of conservation of mass , “ Mass can neither be created nor be destroyed during any chemical change”.
So the number of atoms on both RHS and LHS must be equal in the chemical equation.
We have to check the total number of atoms on RHS is equal to the total number of atoms on RHS.
If the total number of atoms on LHS is not equal to RHS , then we have to balance the equation.
here are some steps to balance a chemical reaction. for understanding it better lets take an example that can help us:-
Fe + H2O ——–> Fe3O4 + H2
the above reaction which is not balanced but it simply tell us about the reactants and products is a Skeletal chemical equation.
now lets balance it, you are adviced to read it again and again.
1. Step 1 :- write down the complete chemical equation and make separate brackets around the formulae. lets take an example As shown below:-
(Fe) + (H2O) ——–> (Fe3O4 ) + (H2)
Step 2 : the number of atoms of different elements present in unbalanced equation.
Element | Number of atoms on LHS (reactants) | Number of atoms on RHS (products) |
Fe | 1 | 3 |
H | 2 | 2 |
O | 1 | 4 |
Step 3 : (a) start from balancing the compound containing maximum number of atoms. This can be a reactant or product.
(b) now select the element with maximum number of atoms.
So from here we can choose Fe3O4 and balance the O first.
Atoms of Oxygen | In reactants | In Products |
(i)Initial (ii)To balance | 1 (in H2O) 1 X 4 | 4 (in Fe3O4) 4 |
(Fe) + 4 (H2O) ——–> (Fe3O4 ) + (H2)
Step 4: Now balance H atoms similarily.
Atoms of hydrogen | In reactants | In products |
(i)Initial (ii)To balance | 8 (in 4H2O ) 8 | 2 (in H2 ) 2 X 4 |
(Fe) + 4 (H2O) ——–> (Fe3O4 ) + 4 (H2)
Step 5: Now balance Fe atoms similarily
Atoms of Iron | In reactants | In products |
(i)Initial (ii)To balance | 1 (in Fe) 1 X 3 | 3 (in Fe3O4 ) 3 |
3(Fe) + 4 (H2O) ——–> (Fe3O4 ) + 4 (H2)
Step 6: check for the corrections , count the number of atoms on LHS and RHS after removing the brackets.
3Fe + 4 H2O ——–> Fe3O4 + 4 H2
Element | Number of atoms on LHS (reactants) | Number of atoms on RHS (products) |
Fe | 3 | 3 |
H | 8 | 8 |
O | 4 | 4 |
Step 7 :Now put the symbols of physical states in brackets after the formulas
3Fe(s) + 4 H2O(l) ——–> Fe3O4 (s) + 4 H2(g)
(s)- solid, (g)- gas , (l)- liquid
Thanks for reading
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