3. Using the following set of reactions, generate a log Ca vs. pH diagram depicting the solubility of calcite and accounting for hydroxide complexation. 2+ CaCO3(s) Ca²+ + OH H2CO3 HCO3 H₂O log Ksp = -8.48 log K₁ = 4.40 ← Ca2+ + CO3²- ← CaOH+ ← → H+ + HCO3 log Kal,co3 ← → H+ ← → H + CO3 + OH 2- log Ka2,co3 -6.35 -10.33 log Kw = -14.0 Assume this conditional system (closed with solid yet to form; constant CT,C03) can be used to predict Ca solubility in a lime-soda ash chemical precipitation water softening plant. i) If the system is operated at pH 9.30 and the effluent alkalinity is 35 mg CaCO3/L, what is the minimum solubility of Ca in equilibrium with calcite? Report your answer as (mg Ca/L). State any assumptions. ii) If the pH remained constant and the effluent alkalinity increased to 70 mg CaCO3/L, would Ca solubility increase or decrease? Defend your answer (but another log Ca - pH diagram is not required).

3. Using the following set of reactions, generate a log Ca vs. pH diagram depicting the solubility of calcite and accounting for hydroxide complexation. 2+ CaCO3(s) Ca²+ + OH H2CO3 HCO3 H₂O log Ksp = -8.48 log K₁ = 4.40 ← Ca2+ + CO3²- ← CaOH+ ← → H+ + HCO3 log Kal,co3 ← → H+ ← → H + CO3 + OH 2- log Ka2,co3 -6.35 -10.33 log Kw = -14.0 Assume this conditional system (closed with solid yet to form; constant CT,C03) can be used to predict Ca solubility in a lime-soda ash chemical precipitation water softening plant. i) If the system is operated at pH 9.30 and the effluent alkalinity is 35 mg CaCO3/L, what is the minimum solubility of Ca in equilibrium with calcite? Report your answer as (mg Ca/L). State any assumptions. ii) If the pH remained constant and the effluent alkalinity increased to 70 mg CaCO3/L, would Ca solubility increase or decrease? Defend your answer (but another log Ca - pH diagram is not required).

Chemistry

9th Edition

ISBN:9781133611097

Author:Steven S. Zumdahl

Publisher:Steven S. Zumdahl

Chapter15: Acid-base Equilibria

Section: Chapter Questions

Problem 7RQ: Sketch the titration curve for a weak acid titrated by a strong base. When performing calculations...

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