When \(0.684 \mathrm{~g}\) of an organic compound containing only carbon, hydrogen, and oxygen was burned in oxygen, \(1.312 \mathrm{~g}\) of \(\mathrm{CO}_{2}\) and \(0.805 \mathrm{~g}\) of \(\mathrm{H}_{2} \mathrm{O}\) were obtained. What is the empirical formula of the compound?

Stoichiometry is akin to a recipe in chemistry. Just like in cooking, you need the right amount of each ingredient, stoichiometry tells you the exact amount of reactants you need to react together to form products in a chemical reaction. It's based on the conservation of mass where all atoms that enter a reaction must be accounted for in the products.

In the exercise, stoichiometry is used to relate the mass of an organic compound that was burned to the amounts of carbon dioxide and water produced in the reaction. We used the stoichiometric coefficients from the balanced chemical equation for the combustion of an organic compound to understand the amount of each element in the product. The process involves determining the ratios in which the elements combine, which are then used to determine the empirical formula of the original compound.

The molar mass of a substance is the weight of 6.022 x 10²³ (Avogadro's number) of its particles (atoms, molecules, ions, etc.), typically expressed in grams per mole (g/mol). Finding the molar mass is essential for converting between mass and moles of a substance.

In our example, we used the molar masses of carbon dioxide (CO₂) and water (H₂O) to convert the mass of these compounds to moles. Knowing the molar mass of CO₂ is 44.01 g/mol and that of H₂O is 18.02 g/mol, we used these values to find out how many moles of carbon and hydrogen are present after combustion.

Combustion analysis is a method in chemistry for determining the elemental composition of a pure compound by burning it in excess oxygen and analyzing the amounts of products formed. It's particularly useful for organic compounds that are composed of carbon, hydrogen, and oxygen.

The analysis involves measuring the masses of carbon dioxide and water produced, which will later help in quantifying the actual amounts of carbon and hydrogen in the initial compound. Oxygen is then determined by the difference in mass from the original compound. The data from combustion analysis feeds directly into stoichiometric calculations to help determine the empirical formula of the compound.

The mole is a fundamental unit in chemistry used to measure quantity. One mole of any substance contains the same number of entities (like atoms or molecules) as there are atoms in exactly 12 grams of carbon-12, which is approximately 6.022 x 10²³ entities.

In the given exercise, calculating moles was the next step after finding the masses of CO₂ and H₂O. The mass of each compound was divided by its molar mass to find the number of moles of CO₂ and H₂O, which then allowed for the determination of the moles of carbon and hydrogen. For oxygen, we subtracted the masses of carbon and hydrogen from the total mass of the organic compound to find the mass of oxygen, which we then converted to moles.