Vapour pressures of water over saturated solutions of magnesium, calcium, nickel and zinc acetates were determined as a function of temperature. The vapour pressures served to evaluate the water activities, osmotic coefficients and molar enthalpies of vaporization. Molar enthalpies of solution of magnesium acetate tetrahydrate, Delta H-sol(m)(T = 294.71 K; m=0.01 mol.kg(-1))=-(15.65 +/- 0.97 kJ.mol(-1); calcium acetate, Delta H-sol(m)(T = 297.18 K; m=0.01 mol.kg(-1))=-(28.15+/-0.28) kJ.mol(-1); zinc acetate dihydrate, Delta H-sol(m)(T = 297.36 K; m=0.01 mol.kg(-1))=-(22.49+/-0.90) kJ.mol(-1) and lead acetaqte trihydrate, Delta H-sol(m)(T = 297.36 K; m=0.0086 mol.kg(-1)) = (22.46+/-0.94) kJ.mol(-1), were determined calorimetrically. (C) 2001 Academic Press.