Calcuate the molalities of MgSO4 Mg2 and SO4 in a 005000m so

Calcuate the molalities of MgSO4, Mg2+, and SO4 in a 0.05000m solution of MgSO4 at 25 degree and at 250 degree. Find the appropriate log K\'s in Soltherm (logK(25degree)=-2.4). Use a spreadsheet!

Solution

dT = Kf (molality)

(273.15 - 272.72) = (1.858) (molality)

0.43 = (1.858) (molality)

molality = 0.2314

when 0.1000 m solution of sulfuric acid dissociates --> 0.1000 m H+ & 0.1000 m (HSO4)-1
= 0.2000 m

there is an excess of 0.0314 m to account for

the excess molality comes from \"HSO4- ion dissociates to a limited extent into H+ and SO4 2-.\"
for every (HSO4)-1 that is lost by dissociating , an equal (H+) is replacing its concentration
but an additional (SO4)-2 appears

that excess 0.0314 is the molaity of (SO4)-2