Chemical Equation — lesson. Science State Board, Class 8.

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A chemical equation is a short description of a chemical reaction using chemical symbols and formulae.

Every chemical equation contains two parts:

1. Reactants:

Participate substances in a chemical reaction

2. Products:

Formed substances in a chemical reaction

Example:

The above reactions

$CH_4$ and

$2O_2$ substances participate in a chemical reaction, so these are named reactants.

The above reactions

$CO_2$ and

$2H_2O$ substances are formed in a chemical reaction, named products.

The steps involved in writing the skeleton equation:

A skeletal equation is written before the balanced equation of a chemical reaction is written.

Example:

The steps for writing the skeletal equation are listed below.

$Mg + H_{2} {SO}_{4} \to {MgSO}_{4} + H_{2} ↑$

Step 1: Write the symbols and formulae of each reactant on the left-hand side (LHS) and connect them by plus (+) sign.

$Mg$ +

$H_2SO_4$

Here Mg and

$H_2SO_4$ are reactants connected by the plus (+) sign.

Step 2: Followed by an arrow (

$\to$ ) which is interpreted as gives or forms.

Step 3: Write the symbols and formulae for each product on the arrow's right-hand side (RHS).

Here

$MgSO_4$ +

$H_2$

$↑$ are formed products.

Step 4: If the product is a gas, it should be denoted by an upward arrow (

$↑$ ), and a precipitate should be indicated by a down arrow (

$↓$ ).

Step 5: This written equation is called the skeleton equation (unbalanced equation).

Did you find an error?

10. Chemical Equation