Final answer:
In quantitative analysis within chemistry, information is often provided about a substance, necessitating calculations for the product substance; this involves using percent composition, formula mass, and the number of moles to determine or confirm a substance's formula.
Step-by-step explanation:
Calculations for which information is given about a particular substance and additional information is needed concerning the product substance formed by a chemical or physical change; shown on the right side of the arrow in a chemical equation. These calculations are a part of quantitative analysis, which involves the determination of the amount or concentration of a substance in a sample. Understanding the classification (atomic element, molecular element, molecular compound, or ionic compound) of each substance is often necessary.
Sometimes, to complete such calculations, it is crucial to know the number of particles, such as atoms or molecules, in a sample of a substance or the required quantity for a reaction. This involves calculating the number of moles from mass measurements and vice versa, using the known chemical formula. When the formula is unknown, percent composition and experimental mass measurements can be utilized to derive it. For compounds with a known empirical or molecular formula, the percent composition can help to detail its constitution, further aiding in the confirmation of the compounds' formula.
The formula mass of a substance, a key concept in these calculations, is the sum of the atomic masses of all atoms in a substance's formula. To determine the formula mass, each atom's mass is added, considering that the formula represents an electrically neutral entity. Problems in quantitative analysis may involve given formulas requiring the calculation of the percentage by mass of each element or given percentage compositions for deriving formulas.