Question

2. What prior knowledge is necessary before balancing a chemical equation?

Answer 1

Part 1:

• A symbolic representation of the changes which occur in a chemical reaction, expressed in terms of the formulae of the molecules involved, is called a chemical equation.
• Reactants are substances that are consumed or react in a chemical reaction whereas products are substances that are produced during a chemical reaction.
• In general, we write the chemical reaction :
  Reactant → Product
• In a balanced equation, the reactant is written on the left-hand side of the arrow, while the product is written on the right-hand side of the arrow.
• An equation in which the number of each atom of an element on the reactants side is equal to the number of each atom of an element on the product side is called a balanced equation.

Part 2:

• The first step in balancing a chemical equation is to identify your reactants and your products.
• Next, you need to determine how many atoms of each element are present on each side of the equation
• It's critical to keep two things in mind while you're balancing reactions. To determine how many of each element are in the reaction, first, never change the subscripts, only the coefficients, and second, always multiply the coefficient by the subscript.
• For example, an unbalanced equation, as shown here

${\mathrm{H}}_2+{\mathrm{O}}_2\to {\mathrm{H}}_2\mathrm{O}$

• To make them equal, we need to adjust the number of atoms of some of the substances until we get equal numbers of each type of atom on both sides.
• Therefore, the balanced equation will be:

$\underset{\mathrm{Hydrogen}\mathrm{Oxygen}\mathrm{Water}}{2{\mathrm{H}}_2+{\mathrm{O}}_2\to 2{\mathrm{H}}_2\mathrm{O}}$