We use the the dilution equation expressed as M1V1 = M2V2 where the terms with subscripts of one represent the initial conditions for the concentrated solution while the terms with subscripts of two represent the final conditions for the diluted solution. Rearranging the dilution formula to calculate for the molarity M2 of the diluted solution M2 = M1V1 / V2 = (0.80M * 0.225L) / 1.0L = 0.18 M