Calculate the number of H₃O⁺ ions in 1.0 mL of pure water at 25 °C.

The amino acid glycine (H₂N–CH₂–COOH) can participate in the following equilibria in water:

H₂N–CH₂–COOH + H₂O ⇌ H₂N–CH₂–COO^– + H₃O⁺ K_a = 4.3 × 10^-3

H₂N–CH₂–COOH + H₂O⇌ ⁺H₃N–CH₂–COOH + OH^- K_b = 6.0 × 10^-5

(b) What is the pH of a 0.050 M aqueous solution of glycine?

At 50 °C, the ion-product constant for H2O has the value Kw = 5.48 * 10-14. (a) What is the pH of pure water at 50 °C? (b) Based on the change in Kw with temperature, predict whether ΔH is positive, negative, or zero for the autoionization reaction of water: 2 H2O1l2 Δ H3O+1aq2 + OH-1aq2

Atmospheric CO2 levels have risen by nearly 20% over the past 40 years from 320 ppm to 400 ppm. (a) Given that the average pH of clean, unpolluted rain today is 5.4, determine the pH of unpolluted rain 40 years ago. Assume that carbonic acid 1H2CO32 formed by the reaction of CO2 and water is the only factor influencing pH. CO21g2 + H2O1l2 Δ H2CO31aq2

The amino acid glycine (H₂N–CH₂–COOH) can participate in the following equilibria in water:

H₂N–CH₂–COOH + H₂O ⇌ H₂N–CH₂–COO^– + H₃O⁺ K_a = 4.3 × 10^-3

H₂N–CH₂–COOH + H₂O⇌ ⁺H₃N–CH₂–COOH + OH^- K_b = 6.0 × 10^-5

(a) Use the values of Ka and K_b to estimate the equilibrium constant for the intramolecular proton transfer to form a zwitterion: H2N–CH2–COOH ⇌ ⁺H₃N–CH₂–COO^–