Answer:
At first, we should know their molecular formula and symbol. In case of element, symbols are written. But in case of compound, molecular formula is used. Also we should know their coefficient (number) to make the number of atoms either side equal.
Air pollution; smoking in the house
B . to supply energy for splitting the water molecules
Plastics clearly constitute an important component of the range of materials used in modern society. Almost all aspects of daily life involve plastics or rubber in some form or the other. ... Owing to their light weight, plastics reduce transportation costs and, therefore, atmospheric carbon dioxide emissions./Plastic is durable and provides protection from contaminants and the elements.