[Nathan001]

hi,  would really appreciate help with these: please

A seawater sample was analysed and found to have an alkalinity value of 2.38mM and a total dissolved inorganic carbon content of 2.03mM. What is the pH of this solution?
(Ka for HCO3- is 1x10-9)


A saturated solution of calcium carbonate has a concentration of 9.3 x 10-5M. What is the solubility product?

CaCO3--------->Ca2+ + CO32-


The concentration of fluoride in standard seawater is 1.3 ppm.  What is this concentration in moles per litre? (atomic mass of F: 19)

[BillJames]

First question: I would have just used the way pOH to calculate the -logarithm of the concentration of OH-, and then derive pH from there... but this method seems to easy to be true. I say, you might have to utilise the formula Activity = Activity Coefficient x Concentration of ion

(Look up extended Debye equation)

Regards,
Bill