Question: how to tell how many ions are in a solution?
Answer: So 1 mole of NaCl weighs 58.5g. So now we need to convert grams into moles by dividing mass in grams by the mass of 1 mole. This means that in 1dm3 of solution there must be 1 mole of sodium ions. The number of particles in 1 mole is given by the Avogadro Constant which is equal to 6.02x1023mol−1 .