a) What is a balancing equation?
b) Write the steps involved in the balancing a chemical reaction.
c) Balance the equation `C_(3)H_(8)+O_(2)rarr CO_(2)+H_(2)O` step by step.

Explanation

i) A chemical equation in which the number of atoms of different elements on the reactant side are same as those on product side is called a balanced reaction.
Step :1
a) Write the equation with the correct chemical formulae for each reactant and product.
Eg : The skeleton equation of combustion of propane is `C_(3)H_(8)+O_(2)rarr CO_(2)+H_(2)O`
Step : 2
a) Compare number of atoms of each element on both sides.
b) We should put suitable numbers as the coefficients before the formula to balance the total number of atoms on both sides of an arrow mark.
c) In this case `C_(3)H_(8)`, the most complex substance, Better to start with it.
Look at the carbon (C)
i) By observing there are 3 carbon atoms on the left side, but only one atom on the right side.
ii) If we add 3 to `CO_(2)`, then the equation is `C_(3)H_(8)+O_(2)rarr 3CO_(2)+H_(2)O`.
Look at the hydrogen (H)
ii)By observing there are 8 hydrogen atoms on the left side, but only two atoms on the right side.
If we add 4 to `H_(2)O`, then the équation is `C_(3)H_(8)+O_(2)rarr 2CO_(2)+4H_(2)O`.
Look at the oxygen (O)
iv)By observing there are 2 oxygen atoms on the left side, but 10 atoms on the right side.
If we add 5 to `O_(2)`, then the equation is `C_(3)H_(8)+5O_(2)rarr 3CO_(2)4H_(2)O`
d) Therefore, the equation is balanced.
Step : 3
a) Check whether all the coefficients of the substances has a common factor.
b) If so, divide those by common factor to obtain lowest ratio of the substances.
Eg : In the above balanced equation `C_(3)H_(8)+5O_(2)rarr 3CO_(2)+4H_(2)O`, no common factor of the coefficients.
c) Hence no need to divide.
Step : 4
a) Verify the equation for the balancing of atoms number and kind wise on both sides of the equation.
Eg : In the above equation number of carbon atoms in left side is 3 and right side is 3.
Number of hydrogen atoms in left side is 8 and right side is 8.
Number of oxygen atoms in left side is 10 and right side is 10.
b) Both sides are equal.
c) Hence the equation is balanced.