How to balance a chemical equation

Do you know how to balance a chemical equation? In the below article you will find the simple and the easiest way to balance a chemical equation. You will also find the meaning of chemical reaction, the chemical equation, and the advantages of the chemical equation.

Chemical Reaction

When elements or compounds react with some other elements or compounds to form a new compound, it is called a chemical reaction. E.g., zinc reacts with dilute sulphuric acid to form zinc sulphate and hydrogen.
Zn + H2SO4= ZnSO4 +H2
Hydrochloric acid reacts with sodium hydroxide to form sodium chloride and water.
NaOH + HCl = NaCl + H2O

Chemical Equation

A chemical reaction may be represented by symbols and chemical formulae. In this representation, reactants are written on the left side and products on the right side with an arrow placed between the reactants and the products. The arrow points towards products. The above-mentioned representation exhibiting the group of reactants and products is called a chemical equation.

Method for writing the chemical equation

The method of writing a chemical equation is as below:

  1. Reactants taking part in a chemical equation are written on the left-hand side and a plus sign (+) is written between them.

  2. products formed in a chemical reaction are written on the right-hand side and (+) sign is written between them.

  3. between reactant and products sign of equality (=) or an arrow is placed. It shows the direction in which the reaction proceeds, i.e., Reactants = Products.

  4. The reactants and products of the reaction are written in terms of their molecular formulae or symbols. The equation is called a skeleton equation. For example:
    Cu + O2= CuO

  5. Compound are written in the form of molecular formulae while elements other than H2, N2, Cl2, Br2, I2, etc. are written in atomic form.

  6. Now, on both sides of the sign of equality or an arrow, the number of atoms is made equal. This is called balancing of an equation and the resulting equation that is formed after balancing is called a balanced chemical equation. But to balance an equation, the chemical formulae are never changed.

Balancing a chemical equation

According to Dalton's theory, atoms are neither created nor destroyed during chemical changes. Therefore, the number of atoms of reactants and products in a chemical reaction must be equal. Hence, the reaction should be balanced on both sides of the arrow (?). Two methods are in use for the balancing of chemical equations Hit and Trial method and partial equation method. In this article, I am providing you with the other simple and easy method to balance a chemical equation.

  1. First, write the formulae of reactant and product in a chemical equation. For example when methan is react with oxygen it forms carbon di oxide and water. So, we will write it as:
    CH4 + O2 = CO2 +H2O

  2. Now, give variable a,b,c,d,--- for reactants and products.
    aCH4 + bO2 = c CO2 +dH2O

  3. Now make the equation for every elements of reactant and products as below:
    For Carbon: a=c, For Hydrogen: 4a=2d, For Oxygen: 2b=2c+d

  4. Let a=1 (you can assume any number) and by puting this value in to different equations, find the value of b,c,d, ----.
    1= 1
    Hence a=1 and c=1
    On taking second equation:
    4a = 2d
    4×1 = 2d
    4= 2d
    Now, on taking third equation:
    2b = 2c + d
    2b =2×1 + 2
    2b = 4

  5. Now put these values of a,b,c and d in the main equation:
    aCH4 + bO2 = c CO2 +dH2O

  6. CH4 + 2O2 = CO2 +2H2O.
    Now it is a balanced chemical equation.

If you have any problem you can ask in the comment box below the article.

Advantages of a chemical equation

The following information is gained by a chemical equation:

  • Knowledge about reactants and products.

  • Number of molecules of reactants and products can be known.

  • If the atomic masses of elements are known, stoichiometric calculations can be made.

  • The law of conservation of mass is verified because the total mass of reactants is equal to that of products.

  • Equivalent quantities can be known.

  • Volume of gaseous reactants or products can be known.

  • If reactants and products are gaseous then volumetric relations between them can be known.

  • Comments

    Author: DR.N.V. Srinivasa Rao14 Jun 2020 Member Level: Platinum   Points : 6

    We all know that matter can't be destroyed or created. But we can convert one form the matter to another form. Based on this fact only all chemical reactions will be made. The total mass of all the materials which are formed in the reaction should be equal to the mass of all the materials which are involved or taken part in the reaction.

    If we take a small equation of water formation ie H2 + O2 = H2O
    The materials which are taking part in the reaction are H2 and O2. The product formed in the reaction is H2O.
    The mass of the reactants O2 is 32, H2 is 2 and H2O is 18. There are two Oxygen atoms in the reactants and only one in the products. To make them two in the products also a minimum of two water molecules are to be formed
    H2 + O2 = 2H2O. Now the oxygen atoms on both the sides are equal. But what about Hydrogen? Now in the products, there are 4 Hydrogen atoms. So you should have 4 Hydrogen atoms on the reactants side also. Now the reaction has to be written as 2 H2 + O2 = 2H20. 4 atoms of Hydrogen and 2 atoms of Oxygen took part in the reaction. The same number of Hydrogen and Oxygen atoms are in products also. If you take the mass into consideration, the total mass of reactants is 2X2 + 2 X 16= 4+32 = 36. The total mass of products is 2 X 18 = 36.
    In this way also one can balance the chemical reaction.

    The author has explained the reaction balancing concept very well and it will be very useful to the students. He has also narrated the importance of writing chemical reactions also.

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