Molar mass and molecular weight can be confusing, but let's break it down simply:

• Molar Mass: Think of molar mass as the weight of one mole of a substance. It's measured in grams per mole (g/mol). To find it, we use the atomic masses listed in the periodic table. For example, water ($H_2O$) has a molar mass of about $18.02 \, g/mol$.

• Molecular Weight: This is a number that doesn't have any units. It compares the weight of a molecule to a special unit called the unified atomic mass unit (u). In other words, molecular weight is like an easier way to express molar mass using this atomic unit.

So, to sum it up:

• Molar mass helps us do practical work in the lab.

• Molecular weight is more about understanding the theory behind molecules.

Both terms are related, but they serve different purposes!