Perusing my CRC the other day, I noticed that sodium sulphate
heptahydrate has a solubility of 19.5g/100cc. The anhydrite has a
solubility of 4.76g/100cc. At a concentration of say 18 g/100cc why
doesn't the heptahydrate crystallise out as the anhydrite then
reabsorb water into its structure to become the heptahydrate and then
redissolve? The respective MWs of 142 and 268 don't account for the
discrepancy. Any ideas?
14 years ago