Question

How to get to know the product of reactants in chemical equation.

Answer 1

Chemical reactions are of the type:

1) Synthesis : where two reactants combine to form one product.
A+ B --> C
CaO + CO2 --> CaCO3

2) single displacement: where 2 elements are substituted for another element in a compound.
AB + C → AC + B.
Single Diplacement Adding hydrochloric acid to zinc will cause a gas to bubble out:
Zn + HCl --< ZnCl2 + H2

3) Double Displacement Reactions

In these reactions, two compounds swap components, in the format AB + CD → AD + CB

This is also called an "exchange". Here are the examples below:

For example: HCl + NaOH ----> NaCl + H2O

4)Decomposition Reactions
These are the opposite of synthesis reactions, with the format AB → A + B. Decomposition reactions "take things apart". Just as synthesis reactions can only form one product, decomposition reactions can only start with one reactant.
For example
CaCo3(s) --> CaO(s) + Co2(g)

5) Combustion
It is the combination of a substance with oxygen. The products are carbon dioxide, water.
CH4 + 2O2 --> CO2 + H2O