Density:

Density is the measure of the mass per unit volume of a material (density = mass/volume). It is a feature of a substance; mass and volume are not.  Mass and volume vary along with size but density will remain constant then temperature will affect the density of a substance and the temperature at that density for which substance was determined is commonly reported along within the density value.

Molarity:

A meaningful way to express exact concentrations of solutions is molarity.  It is described as moles of solute per liter of solution.  Molarity is symbolized through the capital letter M. It could be expressed mathematically as follows.

molarity (M)  = moles of solute (n)/ liters of solution (V)

Remember in which the moles of solute are divided through the liters of solution not solvent.  1 liter of one molar solution will consist of one mole of solute plus sufficient solvent to make a last volume of one liter.