The Blueprint of Water

Carbonated Water: Problem Set

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⟵ 05 Carbonated Water (Engineering Notes) · Contents · 05 Carbonated Water (Answer Key) ⟶

Carbonated Water: Problem Set

“These are only provided to reinforce understanding. The Engineering Notes contain some of the information that will be required. Make sure to employ dimensional analysis for all unit conversions.”

Level 1: Conceptual Mastery

  1. Henry’s Law governs gas solubility. How does it differ from the way ionic solids dissolve? Use the language of “pushed” versus “pulled.” (Refer to Chapter 3 if needed).

  2. Write the full carbonate equilibrium expression. In one sentence, explain what determines which species dominates at any given moment.

  3. Why is bicarbonate considered a buffer? What dual role does it play?

  4. A cooling tower operator stops feeding acid. No chemicals are added, yet the pH rises from 7.5 to 8.8. Explain why, using the concepts of CO₂ stripping and equilibrium shift.

Level 2: Applied Thinking

  1. A cooling tower makeup has 250 ppm alkalinity as CaCO₃. Convert to (a) meq/L and (b) eq/L.

  2. A water sample shows P-alkalinity = 80 ppm and M-alkalinity = 240 ppm (both as CaCO₃). Which alkalinity species are present? Calculate the bicarbonate and carbonate alkalinity.

  3. A boiler’s feedwater M-alkalinity is 15 ppm as CaCO₃. Estimate the CO₂ concentration in the steam/condensate and the neutralizing amine demand at 2.5 ppm amine (active) per 1 ppm CO₂.

Level 3: System Integration

  1. A boiler sample shows P-alkalinity = 400 ppm and M-alkalinity = 450 ppm (both as CaCO₃). Identify the species present, calculate the OH– alkalinity, and estimate the pH. Remember that for hydroxide, eq/L = mol/L.

  2. The chapter describes two strategies for managing carbonate in boilers: neutralize alkalinity upstream or neutralize acidity downstream. In 2–3 sentences, explain what each approach targets and why alkalinity must be controlled either way.

  3. The chapter opens with a story about 2,000 pounds of scale depositing on cooling tower fill after an acid feed failure. Using carbonate equilibrium, explain the chain of events: what left the water, what shifted, what formed, and why pH was the gatekeeper.

Problem notes

Each problem as its own linked note.

5.1 · 5.2 · 5.3 · 5.4 · 5.5 · 5.6 · 5.7 · 5.8 · 5.9 · 5.10

⟵ 05 Carbonated Water (Engineering Notes) · Contents · 05 Carbonated Water (Answer Key) ⟶

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