Average seawater has the following chemical composition in ppm (or mg/L): 

In this problem, you cannot assume that a = m, so you will have to calculate activities for some species using the Truesdell-Jones equation. Answer the following and state your assumptions:
a) What are these concentrations in moles/kg?
b) Do the charges balance (total + = total -)?

c) Would NaCl precipitate from this water i.e. calculate the state of halite saturation (SI index), where: