Formulae & Chemical Equations-Types of Chemical Equation

A chemical equation is a mathematical representation of a chemical reaction. Reactants are substances that begin the chemical reaction and are written on the equation’s left side. Substances formed as a result of the chemical reaction are referred to as products and are represented on the right side of the equation. The coefficients next to the entity symbols represent the number of moles of a substance created or consumed during the chemical process.

Multiple types of chemical equations result from the interaction of products and reactants.

Chemical Equation

A chemical equation is composed of the chemical formulas of the reactants on the left side and the products on the right side. An arrow sign  distinguishes the reactants from the products.  A “+” symbol distinguishes one chemical substance from another. The state of matter of each compound is stated in subscript next to the compound by an abbreviation in parentheses. Chemical equations must be balanced in order to follow the rule of conservation of matter. 

A chemical equation is a representational description of a chemical reaction in which the reactants and products are stated using chemical equations.

6CO2 + 6H2O → C6H12O6 + 6O2 is an example of a chemical equation representing photosynthesis.

Types of Chemical Equations

There are five common types of chemical equations. 

• Combination reaction: A compound is formed when two or more chemicals come together to generate a new one. 

X + Y → XY

To understand this equation, Hydrogen & oxygen gas combine to form carbon-di-oxide. C+O2→CO2

• Decomposition reaction: The inverse of a combination reaction, in which a complex chemical compound molecule is broken down into simpler ones.

XY → X + Y

To understand this equation, Hydrogen & oxygen gas combine to form water. 2H2+O2→2H2O

• Precipitation reaction: When two soluble salt solutions are combined, an insoluble solid called precipitate is formed.

Soluble salt X + soluble salt Y → Precipitate + soluble salt Z

To understand this equation, Silver nitrate & Potassium chloride combine to form  AgCl which is the precipitate formed+Potassium nitrate

AgNO3 + KCl →AgCl + KNO3.

• Neutralisation reaction: An acid interacts with a base resulting in salt and water.

Acid + Base → Salt + Water

To understand this equation, Hydrogen chloride acid +Sodium hydroxide gives Sodium Chloride +Water.

HCl+ NaOH →NaCl + H2O

Displacement reaction: One element substitutes for another.

• X + YZ → XZ + Y

A twofold displacement reaction occurs when silver nitrate and sodium chloride react. The silver exchanges its nitrite ion for the chloride ion of sodium, leading the sodium to start picking up the nitrate anion.

AgNO3 + NaCl → AgCl + NaNO3

Let’s understand the types of chemical reactions in detail now:

• Combination reaction

A combination reaction occurs when two or more chemicals come together and combine to generate an individual product. Example of combination reaction is illustrated as Ba + F2  BaF2

• Decomposition reaction

A decomposition reaction occurs when a single chemical breaks down into two or more smaller compounds. Example for a decomposition reaction is illustrated as H2CO3 (aq.) → CO2 (g) + H2O (l)

• Displacement reaction

A chemical change that occurs when a higher reactive component displaces an element which is much less reactive, out of its aqueous salt solution. Example for a displacement reaction is illustrated as 2K +2H2O→ 2KOH + H

• Double Displacement reaction

A double displacement reaction is a chemical process in which the available ions are swapped between two available reactants to generate a new molecule. Example for a double displacement reaction is illustrated as BaCl2 (aq) + Na2SO4 (aq)→ BaSO4 (s) + 2NaCl (aq)

• Precipitation Reaction

Precipitation reaction refers to a chemical reaction which results in the development of a product which is insoluble and called precipitate. Although the reactants reflect as liquid, the product generated is insoluble as well as separates like a solid. The chemical equations of the precipitation reaction is illustrated with this balanced chemical equation: AgNO3(aq) + NaCl(aq) —- AgCl↓ + NaNO3 (aq)

Conclusion

A chemical equation is made up of the chemical formulae of the reactants reflecting on the left side and the products reflecting on the right side. An arrow symbol “→” is commonly read as ‘yields’ to separate the reactants from the products. A “+” sign separates the chemical formulas of each particular substance from those of others. Each compound’s or molecule’s state of matter is given in subscript next to the compound by an abbreviation in parenthesis. To satisfy the law of conservation of matter, which confirms that matter is no way lost or newly created in a closed system, chemical equations must be balanced. 

The 5 primary types of chemical reactions are:

1. Combination reaction
2. Decomposition reaction
3. Displacement reaction
4. Double Displacement reaction
5. Precipitation Reaction