Molar mass is a fundamental concept in chemistry, representing the mass of one mole of a specific chemical substance. This measurement is expressed in units of grams per mole (g/mol). Determining this value allows chemists to accurately measure and combine substances in a laboratory setting. This article explores the molar mass of the inorganic compound sodium bromide (NaBr), a common salt used in various industrial and chemical applications.
Identifying the Necessary Components
To calculate the molar mass of sodium bromide (NaBr), the first step involves identifying the atomic mass for each element present. The formula NaBr indicates that the compound is composed of one atom of sodium (Na) and one atom of bromine (Br). These atomic masses are established values found on the Periodic Table of Elements.
The atomic mass for sodium is approximately \(22.990 \text{ g/mol}\). This value represents the weighted average mass of a sodium atom. The atomic mass for bromine is approximately \(79.904 \text{ g/mol}\).
Calculating the Total Molar Mass
The total molar mass of sodium bromide is found by adding the atomic masses of the individual elements identified in the formula, NaBr. Since the calculation involves a one-to-one ratio of elements, it is a straightforward sum. The mass of one mole of sodium (\(22.990 \text{ g/mol}\)) is combined with the mass of one mole of bromine (\(79.904 \text{ g/mol}\)).
Performing this addition (\(22.990 \text{ g/mol} + 79.904 \text{ g/mol}\)) yields the molar mass of sodium bromide. The calculation results in a value of \(102.894 \text{ g/mol}\). This figure represents the total mass of the compound contained within a single mole.
Understanding the Calculated Value
The calculated molar mass of \(102.894 \text{ g/mol}\) provides a direct link between the microscopic world of atoms and the macroscopic measurements of the laboratory. If a chemist weighs out \(102.894\) grams of sodium bromide, they have exactly one mole of the substance. One mole contains Avogadro’s number of particles, which is approximately \(6.022 \times 10^{23}\) formula units of NaBr.
This conversion factor is useful in stoichiometry, the area of chemistry that deals with the quantitative relationships between reactants and products. The molar mass is routinely used to convert a desired number of moles into a measurable mass in grams that can be weighed on a balance. The ability to switch between moles and grams is also necessary for preparing solutions of a specific concentration.