Explain the rules for writing a chemical equation.

Certain rules have to be followed in writing a chemical equation
1. The reactants taking part in the reaction are written in terms of their symbols or molecular formulae on the left-hand side of the equation.
2. A sign of plus(+) is added between the formulae of the reactants.
3. The products of reaction are written in terms of their symbols or molecular formulae on the right-hand side of the equation.
4. A sign of plus (+) is added between the formulae of the products.
5. In between the reactants and the products an arrow sign(→) is marked to show which way the reaction is occurring.
A + BC + D
In this chemical equation, A and B are the reactants, and C and D are the products. The arrow indicates that the reaction proceeds towards the formation of C and D. 6. Special conditions, such as heat or electrical current, needed to bring about a reaction are mentioned are the arrow mask.
2KNO₃ 2KNO₂ + O₂
2H₂ + O₂ 2H₂OSodium chloride solution gives a white curdy white precipitate of silver chloride when it reacts with silver nitrate solution.Reactants: Sodium chloride NaCl and silver nitrate AgNO₃
Products: Silver chloride AgCl and sodium nitrate NaNO₃
Condition: mixing at room temperature
Sodium chloride + silver nitratesilver chloride + sodium nitrate
NaCl + AgNO₃ AgCl + NaNO₃
NaCl + AgNO₃AgCl + NaNO_3.