Question

How to balance chemical equations step by step as required in CBSE board exams?

Answer 1

1. When balancing equations, remember the number of atoms of each element needs to be the same on both sides of the equation.
2. The coefficients (numbers in front of a species) are multiplied by every atom in that chemical.
3. The subscripts are multiplied only by the affected atom.
4. To start balancing, begin with less-common elements, like metal atoms or oxygen, and leave hydrogen atoms for last (they are usually the easiest to balance).
5. Be sure to tally of all the atoms of each element on each side of the equation. Are they the same? If not, rework the coefficients and subscripts.

for example :

S8 + O2 ----> SO2

Count the atoms on each side
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S=8 S=1
O2 O=2

Only change the Cofficients
S8 + 8O2 -----------> 8SO2
________________________
S=8 S = 1*8 = 8
O=2*8 = 16 O = 2*8 = 16