The Olivine normally crystalizes first from the magma of the mafic minerals, It crystalizes at between 1200°C and 1300°C. when the temperature of magma drops and there is a silica still remains in the magma so the olivine reacts with this silica to form pyroxene.and by more cooling of the temperature of magma and there is a silica still remains in magma pyroxene change to amphibole, and amphibole to biotite.when the pyroxene strat to form the plagioclase feldspar also forms.
You HAVE TO know that molarity (M) tells you the number of moles of a solute per Liters of solution. M=mol/L 0.3M = 2.7 mol/ Volume Volume = 2.7 mol/3.0 L Volume = 0.9 L