pH and Buffers Lecture

Vocabulary flashcards covering fundamental terms and concepts from the lecture on pH, buffers, and acid-base disturbances.

pH

Negative logarithm of the hydrogen-ion concentration (pH = –log[H⁺]); rough measure of a solution’s acidity.

pOH

Negative logarithm of the hydroxide-ion concentration (pOH = –log[OH⁻]).

Kw

Ion-product constant of water; at 25 °C Kw = 1.0 × 10⁻¹⁴ = [H⁺][OH⁻].

Autoionization of water

Self-ionization reaction in which 2 H₂O ⇌ H₃O⁺ + OH⁻.

pH scale

0–14 scale; 7 is neutral,

Acidosis

Blood pH below normal (≈7.35); caused by excess CO₂ or deficit of HCO₃⁻.

Respiratory acidosis

Acidosis due to hypoventilation; carbonic acid (H₂CO₃) excess.

Metabolic acidosis

Acidosis from acid accumulation (e.g., ketones, Cl⁻) that lowers bicarbonate.

Alkalosis

Blood pH above normal; results from excess HCO₃⁻ or loss of CO₂.

Respiratory alkalosis

Alkalosis caused by hyperventilation; carbonic acid deficit.

Metabolic alkalosis

Alkalosis from loss of Cl⁻ (e.g., vomiting) or excess bicarbonate ingestion.

Hypoventilation

Reduced breathing rate that retains CO₂ and can lead to respiratory acidosis.

Hyperventilation

Rapid breathing that expels CO₂ and can cause respiratory alkalosis.

Buffer

Mixture of a weak acid and its conjugate base that resists pH changes.

Phosphate buffer

Laboratory buffer that showed effective pH resistance in Procedure B.

Bicarbonate buffer system

Major plasma buffer consisting of H₂CO₃/HCO₃⁻; regulated by CO₂ exchange.

Henderson–Hasselbalch equation

pH = pKa + log([A⁻]/[HA]); relates pH to acid/base ratio in a buffer.

Homeostasis

Maintenance of stable internal conditions; proper pH is essential for it.

Hyperkalemia

Elevated blood K⁺; a serious problem associated with pH disturbances.

Partial compensation

Physiological adjustment that moves pH toward normal but not fully corrects it.

Complete compensation

Adjustment that restores pH to normal range by balancing H₂CO₃/HCO₃⁻ ratio.

Normal blood pH

Arterial: 7.35–7.45; venous: 7.33–7.47; deviations ≥0.2 units are serious.

Ketones

Acidic metabolic products that accumulate in metabolic acidosis.

pKa

Negative logarithm of an acid’s Ka; used in buffer calculations.