How do you calculate concentration in mol/dm³?

You calculate concentration in mol/dm³ by dividing the number of moles of solute by the volume of the solution in dm³.

Concentration is a measure of how much solute is dissolved in a particular volume of solution. In chemistry, it's often expressed in moles per cubic decimetre (mol/dm³), also known as molarity. To calculate this, you need to know two things: the number of moles of solute and the volume of the solution.

The number of moles of solute can be calculated using the formula: moles = mass / molar mass. The mass is the weight of the solute you've added to the solution, and the molar mass is a constant for each substance, usually given in grams per mole (g/mol). You can find the molar mass on the periodic table: it's the relative atomic mass of the element.

The volume of the solution is the total volume, not just the volume of the solvent. It's important to remember to convert the volume to cubic decimetres (dm³) if it's not already in that unit. There are 1,000 cubic centimetres (cm³) in a cubic decimetre (dm³), so to convert from cm³ to dm³, you divide by 1,000.

Once you have these two values, you can calculate the concentration by dividing the number of moles of solute by the volume of the solution in dm³. The result is the concentration of the solution in mol/dm³. This tells you how many moles of solute are present in each cubic decimetre of solution, which is a useful measure of how 'strong' or 'concentrated' the solution is.