The coefficients in a chemical equation represent the

Explanation:

The coefficients are the numbers that you put in front of each chemical formula that represents the reactants and products in the chemical equation. They indicate the mole ratio in which the elements or compounds react to form the products, as per the chemical equation.

See an example:

      This equation is not balanced: the  number of atoms of oxygenin the reactant side is 2 while the number of atoms of oxygen isn the product side is 1. In order to balance the equation you need to add some coefficients.

When no coefficients are shown it is understood that the coefficient is 1.

The coefficients 2 in front of H₂ and 1 (understood) in front of O₂, in the reactant side, and 2 in front of H₂O, in the product side, balance the equation.

Those coefficients mean that the 2 molecules (or mole of molecules) of H₂ react with 1 molecule (or mole of molecules) of O₂ to form 2 molecules (or moles) of H₂O (product side).

That is the mole ratio: 2 H₂ : 1 O₂ : 2 H₂O.

Notice that, in spite of the aboslute numbers may change, the mole ratio is unique for any chemical reaction.  For example 4 : 2 : 4 is the same ratio that 2 : 1 : 2, or 8 : 4 : 8, but the most common practice is to use the most simple form of the ratio, i.e. 2: 1: 2.

  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-

catya that's not even a b or c