Chemical equations are symbolic representations of chemical processes in which the reactants and products are expressed in terms of their chemical formulae. They also utilize symbols to express aspects such as response direction and the physical properties of the responding entities. In 1615, the French chemist Jean Beguin developed the first chemical equations.
Chemical reactions can be expressed on paper using chemical equations, for example; the reaction between hydrogen gas and oxygen gas to form water.
2H2 + O2 → 2H2O
In the preceding example, the responding entities are written on the left-hand side of the chemical equation, but the products of the chemical reactions are written on the right-hand side. It can also be seen that each of the symbols for the associated reactants and products has a coefficient assigned to it. The coefficients of entities in a chemical equation are the exact value of that entity’s stoichiometric number.
One of the four symbols can be used to distinguish the reactants and products (for which the chemical formulas are stated in chemical equations).
Aside from the stoichiometric coefficients of the responding and generated entities, symbols enclosed in parenthesis are written adjacent to them to describe their physical states during the chemical reaction. These symbols might be any of the ones listed below.
For instance, Zn + H2SO4 → ZnSO4 + H2
Because the numbers of zinc, hydrogen, and sulfate are equal on both sides of this equation, it is a Balanced Chemical Equation.
Mass cannot be generated or destroyed in a chemical process, according to the Law of Conservation of Mass. To be in accordance with this law, the total mass of elements present in reactants must match the total amount of elements present in products.
For instance, Fe + H2O → Fe3O4 + H2
In this case, the amount of atoms of elements on both sides of the reaction is not equal. For example, on the left-hand side, there is just one iron atom, but three iron atoms are present on the right-hand side. As a result, the chemical equation is imbalanced.
A few examples of chemical equations:
H3PO4 + 3KOH → K3PO4 + 3H2O
Na2S + 2AgI → 2NaI + Ag2S
PCl5 + 4H2O → H3PO4 + 5HCl
Electrolytes (substances that break down into ions when dissolved in polar liquids) are separated and expressed as individual ions in ionic chemical equations. These equations are extremely useful for explaining single displacement reactions as well as salt metathesis processes (generally referred to as double displacement reactions).
Example: Chemical Equation: CaCl2 + 2AgNO3 → Ca(NO3)2 + 2AgCl↓
Ionic Equation: Ca2+ + 2Cl– + 2Ag+ + 2NO3– → Ca2+ + 2NO3– + 2AgCl↓
When the reactants and products of the ionic equation and the chemical equation are compared, the Ca2+ (calcium ion) and NO3– (nitrate) ions may be found on both sides of the ionic equation. Because they do not participate in the chemical process, these ions are referred to as spectator ions.
The net ionic equation for the above example may be stated by omitting the spectator ions and simply expressing the reaction between the participating ions, as shown below.
2Cl– + 2Ag+ → 2AgCl↓
This ionic chemical equation may be translated as follows: two chloride ions derived from calcium chloride react with two silver cations derived from silver nitrate, resulting in a precipitate of silver chloride as the product.
They are equations that express chemical processes using chemical formulas and symbols. The reactants are represented on the left side of a chemical equation, while the products are shown on the right. These things are separated by a symbol that represents the reaction's direction. Each reactive entity is also allocated a stoichiometric coefficient.
The chemical equations in which electrolytes are represented as dissociated ions are known as ionic equations. They are frequently used to depict the displacement processes in aqueous media. Some ions engage in these processes, whereas others do not. Ions that do not react are known as spectator ions and are often excluded from the net ionic equation.