You don't need a chemistry degree to read a spec sheet — just a working sense of what a formula and a molecular weight number are actually telling you.
What a Chemical Formula Shows
A formula like NaOH (caustic soda) or Al₂(SO₄)₃ (aluminium sulphate) tells you which elements are present and in what ratio. The subscript numbers count atoms — Al₂(SO₄)₃ has 2 aluminium atoms and 3 sulphate groups per molecule. This matters practically when comparing anhydrous and hydrated forms of the same chemical (see our guide on anhydrous vs monohydrate citric acid) — the hydrated form's formula includes extra water molecules, which is exactly why it weighs more per mole and why dosing calculations need to account for it.
What Molecular Weight Is For
Molecular weight (or molar mass) is the weight of one mole of the substance, and it's the number that lets you convert between a weight-based dose and the actual chemical quantity reacting in your process. Two products with different molecular weights need different weight-based doses to deliver the same amount of active chemical — this is exactly why, for example, switching between caustic soda flakes and caustic potash isn't a simple 1:1 weight substitution even though both are strong alkalis.
A Practical Example
If a process specification calls for a certain molar quantity of alkali and you're switching suppliers or forms, convert both products to the same basis (moles of active alkali, not just kilograms of product) before comparing dose rates or cost per treatment. Our technical team can help with this conversion for any product on our site — it's a common point of confusion when switching grades.