Final answer:
The main purpose of determining the molar mass of a metal in a lab report is to identify the metal by comparing the calculated molar mass to known values. Molar mass is the mass of one mole of a substance and is important for conversions and analyzing substances in chemistry. The correct option is 3.
Step-by-step explanation:
The purpose of the determination of the molar mass of a metal in a laboratory report is primarily to identify the metal based on its molar mass. By knowing the molar mass, which is the mass of one mole of a substance, we can compare it to known values and determine the identity of the metal.
It's important to note that atomic mass and molar mass are closely related, as the atomic mass of an element, expressed in atomic mass units (amu), is the mass of a single atom, while the molar mass, expressed in grams per mole (g/mol), is the mass of Avogadro's number (6.022 x 1023) of these atoms.
To calculate the molar mass of an element, one would refer to the atomic mass present on the periodic table. However, when dealing with a compound, the procedure involves adding the atomic masses of the individual atoms present in the molecular formula.
This calculation provides the basis for other conversions, such as converting between grams, moles, and the number of particles using dimensional analysis. Understanding molar mass is crucial in diverse laboratory situations, such as when preparing solutions of a known molarity, or when analyzing the composition of unknown substances through elemental analysis or reactions where the amount of product needs to be determined in moles.