Converting between moles, grams and particles
The two formulas that connect moles to grams and to particle counts, worked examples, and how this calculator chains them together.
The mole as a counting unit
A mole is simply a fixed count of things, in the same way a dozen is twelve. One mole is 6.02214076 x 10^23 particles, a value known as Avogadro's number. Chemists count in moles because atoms and molecules are far too small and numerous to count one by one, yet reactions happen in whole-number ratios of particles. The mole turns those invisible counts into masses you can weigh out on a balance.
From grams to moles and back
The bridge between the mass you can weigh and the amount in moles is the molar mass, measured in grams per mole. To go from grams to moles you divide: moles = mass / molar mass. To go the other way you multiply: mass = moles x molar mass. For example, 18 grams of water divided by its molar mass of 18.015 g/mol gives about 0.999167 moles, just under one mole. This calculator applies exactly these relationships whenever both a mass and a molar mass are present.
From moles to particles
Once you know the amount in moles, the particle count follows by multiplying by Avogadro's number: particles = moles x 6.02214076 x 10^23. So one mole of anything contains roughly 6.0221 x 10^23 particles, whether those particles are atoms, molecules or ions. The reverse also holds: divide a particle count by Avogadro's number to recover the moles. Because the tool treats moles as the hub, giving it a particle count lets it work back to moles and then, with a molar mass, on to grams.
Chaining the steps in one place
Real problems often need both jumps in a row, such as going from grams straight to a number of molecules. This calculator does that chaining for you: it first establishes moles from whatever you enter, then fans out to every other quantity it can compute. That means you rarely have to run two separate calculators or keep track of intermediate values. Enter what the question gives you, and read off the piece it asks for.