Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Nathan001 on April 20, 2008, 10:04:18 AM
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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)
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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