# How do you calculate the number of ions in a solution?

##### 1 Answer

Find the molar concentration then look at the formula to work out the concentration of each ion.

Lets look at an example: "How many sodium ions are there in a solution of sodium chloride of concentration

We need to convert this into

So now we need to convert grams into moles by dividing mass in grams by the mass of 1 mole.

So the number of moles of NaCl = 58.5/58.5 = 1 mole

So the concentration of NaCl is

This means that in

The number of particles in 1 mole is given by the Avogadro Constant which is equal to

So the solution in question contains L sodium ions.

Check the stoichiometry of the formula. If you have