Molarity.

Molar concentration is the number of moles of solute in one litre of solution.

Forumla:   Molarity = moles of solute(mol)/ volume of solution(L)

Example: If there is 2.0 of CO2 in 1.0L of solution, what is the molar concentration (molarity)?

M(representing molarity) = 2.0 mol CO2/1.0L

                                      = 2.0M CO2 or 2.0mol/L CO2


For a reaaaally in depth look at molarity check this out!