can you do this #3 for me? Is this analysis suitably accurate for a thermodynami

Question

can you do this #3 for me?

Is this analysis suitably accurate for a thermodynamic analysis? Use both charge balance and TDS to determine if it is acceptable. Use the right-most column for ion stoichiometries; use the left-most column as the chemical term for concentration conveyed by your analyst. The mineral brucite (Mg(OH)_2(s)) precipitates when dilute groundwater reacts with magnesium-rich rocks of the California coast ranges. The reaction consumes hydroxyl ions and there is apparent equilibrium: Mg^+2(aq) + 2 OH(aq) = Mg(OH)_2(s) If I measure the pH of springs near Jenner to be pH=9.5, what can you teH me about the equilibrium activity (concentration) of magnesium in that solution? (Neglect activity coefficient corrections.) You will need to calculate the dissociation constant of water to answer this question: H_2O(l) = H^+(aq) + OH(aq)

Explanation / Answer

H2O (l) = H+(aq) + OH(aq)

The ionic product

Kw = [H+][OH-]= 1×10^-14

pKw = pH + pOH = 14

pH is given ,=9.5

Therefore, pOH = 14 - 9.5 = 4.5

pOH = 4.5

-log[OH-]= 4.5

log[OH-] = -4.5

[OH] = 10^-4.5

Mg+2 (aq) + 2OH- (aq) = Mg(OH)2(s)

Mg+2 = 1/2[OH-] = 1/2 (10^-4.5)

= 0.5 × 10^-4.5

= 1.58 ×10^-5

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