The pH Scale & Strong vs Weak Acids

• What is the pH of aqueous solutions formed by acids?

  Less than seven
• Why do acids have a pH of less than seven?

  They ionize to release hydrogen ions
• What ions does hydrochloric acid dissociate into?

  H⁺ and Cl^-
• What ions does nitric acid dissociate into?

  H⁺ and NO₃^-
• What defines strong acids?

  They ionize completely in solution
• How do weak acids differ from strong acids in ionization?

  Weak acids do not fully ionize
• What does it mean for the ionization of a weak acid to be reversible?

  Equilibrium exists between undissociated and dissociated forms
• What does a double arrow in a dissociation equation indicate?

  The reaction is reversible
• What does it mean when we say the equilibrium lies to the left for weak acids?

  More undissociated acid than dissociated acid
• How is acid strength different from acid concentration?

  Strength is about ionization proportion
• What does concentration measure in relation to acids?

  Amount of acid in a certain volume
• Can strong acids be found in low concentrations?

  Yes, strong acids can be dilute
• What is pH a measure of?

  Concentration of hydrogen ions in solution
• How does pH change with hydrogen ion concentration?

  Higher hydrogen ion concentration lowers pH
• What does a decrease of one on the pH scale represent?

  Hydrogen ion concentration increases by a factor of 10
• If pH changes from 5 to 3, how much does hydrogen ion concentration increase?

  By a factor of 100
• If pH changes from 8 to 11, how does hydrogen ion concentration change?

  Decreases by a factor of 1,000
• How can a strong acid achieve a low pH?

  By fully dissociating at most concentrations
• What must a weak acid be to achieve a low pH?

  Highly concentrated
• At any given concentration, how does the pH of a strong acid compare to a weak acid?

  Strong acid has a lower pH than weak acid
• What determines the pH of a solution?

  The concentration of hydrogen ions