M = moles / V Solving for V, V = moles / M ------------------(1) Also, moles is equal to, moles = mass / M. mass -------------(2) puting value of moles from eq. 2 into eq. 1, V = (mass / M.mass) / M Putting values, V = (45 g / 164 g/mol) / 1.3 mol/dm³