L1 /
11
CH3041
SATURATION OF
SOLIDS
• To work out if an
ionic material is saturated in
seawater we need to work with activities.
• Ion Activity Product IAP = aCationc x aAniond
• Degree
of Saturation W = IAP / Ksp
W > 1
Supersaturation W = 1
Saturation
W < 1 Undersaturation
W < 1 Undersaturation
• Looking at CaCO3 in seawater
when ion
pairing is included W = 3 - 6 (supersaturated)
pairing is included W = 3 - 6 (supersaturated)
• Little abiotic
pptn of CaCO3 from surface waters occurs -
inhibition by other ions.
