Density is defined as the mass per unit volume. formula is as follows we have been given the density and volume so we need to find the mass of ethylene glycol if we rearrange the equation making mass the subject mass = density x volume density = 1.11 g/cm³ this means that 1 cm³ of solution has a mass of 1.11 g since mL = cm³ therefore 387 cm³ of solution has a mass of 1.11 g/cm³ x 387 cm³ = 429.6 g mass of ethylene glycol is 429.6 g