Question

How many grams in 3.75 mol NaBr?

Answer 1

Mole, also pronounced as mol is a standard scientific unit used for measuring large quantities of very small entities such as atoms, molecules, or some other specified particles.

Complete answer:
Avogadro's number is the number of units present in per mole of any substance (defined as its molecular weight in grams), and is equal to the value $6\times {{10}^{23}}$. The units mentioned above may be electrons, atoms, ions, or molecules, depending on the nature of the substance and the character of the reaction (if any).
Avogadro’s constant value was chosen in such a way so that the mass of one mole of a chemical compound expressed in grams becomes numerically equal to the average mass of one molecule of the compound, which is measured in daltons (universal atomic mass units).
Atomic no is defined as the total no of protons present in the nucleus of an atom or total no of electrons present in the orbits surrounding the nucleus.
Mass no is defined as the total no of protons and neutrons present in the nucleus of an atom.
Mass of sodium is 23g and that of bromine is 80g. Therefore mass no of NaBr is 103g.
Now 1mole of NaBr weighs 103g.
Then 3.75 mole of NaBr weighs 386.25.

Note:
That long number is termed Avogadro's number after the first 19th-century Italian scientist Amadeo Avogadro. The mass of 1 mole of something in grams is the mass of that substance in mass units.