How is a chemical equation used to represent a chemical reaction?

1. the atoms on the left side of the arrow are different from the atoms on the right, but are arranged similarly.

2. the atoms on the left side of the arrow are different from the atoms on the right, and are arranged differently.

3. the atoms on the left side of the arrow are the same as the atoms on the right, but are arranged differently.

4. the atoms on the left side of the arrow are the same as the atoms on the right, and are arranged the same.

3. The atoms on the left side of the arrow are the same as the atoms on the right, but are arranged differently.

Explanation:

A chemical reaction is represented by a chemical equation which show the reactant and products. Reactants are written on left side of arrow while products are written on right side. The number of atoms are remain same however arrangement of atoms is different on both side.

For example:

6H₂O + 6CO₂ + energy  →   C₆H₁₂O₆ + 6O₂

it is known from balanced chemical equation that 6 moles of carbon dioxide react with the six moles of water and created one mole of glucose and six mole of oxygen. The number of atoms are same on both side however arrangement of atoms is different.

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-