Chemistry is the science of the composition, structure, properties, and reactions of matter, especially of atomic and molecular systems. In chemistry, all concepts are connected somehow. Each formula relates to a theory, which in turn relates to other theories, formulas, ideas, etc. For example the concepts of scientific notation, significant figures, dimensional analysis, molar conversions, and stoichiometry are all tied into one another. Each member in this series would be impossible to accomplish without the preceding concept. .
One of the first lessons taught in chemistry is that of scientific notation. It is used to express a number or decimal in a different way. Scientific notation is often used to shorten long numbers such as two billion, which simply becomes 2 x 109. This concept, however, needs to use significant figures to know how many numbers to put after the decimal. Significant figures are used to determine the uncertainty of a particular number. When working an equation, every answer must depend on the significant figures in the numbers given. This helps give the most accurate results possible, especially when using large numbers with decimals and such. .
The idea of significant figures is therefore directly related to dimensional analysis, a manner in which one can convert between units by using known equalities. Like it was mentioned earlier, the response for a dimensional analysis problem depends on the significant digits in the given numbers. Dimensional analysis is used to find an answer in a specified unit different than that of the number given. This is imperative in the concept of molar conversions. This uses the idea that one mole is equal to 6.02 x 1022 particles. It is practical to convert units into moles because they relate to mass, volume, and particles. To convert moles into any of these, one would use dimensional analysis to facilitate the process.
Finally, the idea of molar conversions is needed in stoichiometry, which is used to find the quantities used or produced in a reaction.