Question

What is the purpose of writing chemical equations?
A) To know the reactants and products in a chemical reaction
B) To know the no. of moles in a chemical reaction.
C) To know the ratios of reactant and products
D) All of the above

Answer 1

We have to remember that the chemical equation is a representation of a chemical reaction in the form of symbol and formulae, where in the reactant. A chemical reaction can be represented as:
For example: $2{H_2} + {O_2} \to 2{H_2}O$ which is a type of combination reaction.

Complete step by step answer:
The purpose of writing a chemical equation can be seen in many ways:
- By writing a chemical equation we can know about the reactants and products involved in a chemical reaction.
- A balanced chemical equation tells us the no. of atoms of a particular element involved in a reaction.
- By writing a chemical equation; we get to know about the ratios of reactants and products involved in a reaction.
- In a chemical reaction, reactants are the one that are written on the left while products are written on the right hand side.
- While balancing a chemical equation, we can calculate the no. of moles for the given reactant and product.
- “$\to$” this arrow is used to represent a forward reaction.
- Quantity or mass for each element in a chemical reaction remains unchanged, which is stated by a law of conservation of mass.
- Stoichiometric numbers are the numerical numbers written before an element or molecule in a chemical reaction.
- Representation of a chemical reaction:
$Zn + 2HCl \to ZnC{l_2} + {H_2}$
$Zn$ and $HCl$ are the reactants for this chemical reaction whereas $ZnC{l_2}$ and ${H_2}$are the products.

Hence, the correct answer is, ‘Option D’.

Note: Writing a chemical equation will help us to know about the no. of reactants and products involved in a reaction. We have to remember that in chemical reaction, the law of conservation of mass dictates that the quantity of each element does not change.