Here b is used as the symbol for molality (instead of m ) to avoid confusion with the symbol m for mass. The SI unit for H s b p is mol/(kg·Pa). There is no simple way to calculate H s c p from H s b p , since the conversion between concentration c a and molality b involves all solutes of a solution. For a solution with a total of n solutes with indices i = 1 , … … , n , the conversion is: