Te analysis of \(0.922 \mathrm{~g}\) of aniline, a common organic base used in some varnishes, is \(0.714 \mathrm{~g} \mathrm{C}\), \(0.138 \mathrm{~g} \mathrm{~N}\), and the remainder hydrogen. What is the empirical formula of aniline?

Stoichiometry is a branch of chemistry that deals with the quantitative relationship between the reactants and products in a chemical reaction. For a student delving into the realm of chemistry, understanding stoichiometry is tantamount to mastering the balance and proportions inherent in chemical equations. Specifically, when we refer to stoichiometry in the context of finding an empirical formula, we are concerned with the ratio of elements within a compound.

This ratio can be unveiled by balancing the number of moles of each element, derived from the given masses. As per our aniline example, stoichiometry guides us in calculating the moles of carbon, nitrogen, and hydrogen and then using these to determine the simplest whole number ratio of atoms within the molecule. This is akin to deciphering a recipe for the compound, where the empirical formula represents the basic ingredients and their proportions to one another.

The mole is a fundamental unit in chemistry used to quantify the amount of a substance. Mole calculations are vital for converting between mass, number of atoms or molecules, and volume in the case of gases. To clarify, one mole of any substance contains the same number of entities (6.022 x 10^23, Avogadro's number) as there are atoms in 12 grams of carbon-12.

In the context of our aniline problem, we calculate moles by dividing the given mass of each element by its respective molar mass. This process translates the mass of an element into a count of atoms, allowing us to compare and combine different elements within a compound. By establishing the measured quantity as moles, we can then determine their simplest ratio, leading us to the empirical formula.

Molar mass is the mass of one mole of a substance and is expressed in grams per mole (g/mol). It is the bridge between the atomic scale and the macroscopic world we interact with. To determine the molar mass of an element, we reference the atomic weight of the element as listed in the periodic table. For compounds, the molar mass is the sum of the atomic weights of all atoms in the formula.

For instance, when examining aniline in our exercise, molar mass allows us to convert between the mass of a sample and the amount of moles of each element it contains. Molar mass effectively serves as a conversion factor in mole calculations. Therefore, knowing the molar mass of carbon, nitrogen, and hydrogen is imperative to finding the moles of each in the given sample, which in turn allows for the empirical formula of the compound to be determined through stoichiometric analysis.