12. acids and bases

• Who were the chemists behind the Bronsted-Lowry theory?

  Hans Bronsted and Thomas Lowry
• What do Bronsted-Lowry acids do?

  Donate protons
• What do Bronsted-Lowry bases do?

  Accept protons
• What ions are produced when acids mix with water?

  Hydronium ions (H3O+)
• What is the simplified notation for hydronium ions?

  H+
• What do hydroxide ions (OH-) indicate?

  A basic solution
• How do weak acids behave in terms of equilibrium?

  Equilibrium lies to the left, favoring reactants
• What are examples of strong acids?

  Hydrochloric acid, sulfuric acid, nitric acid
• What characterizes strong acids and bases in terms of dissociation?

  They dissociate almost completely
• What is an example of a weak base?

  Ammonia (NH3)
• What is the role of weak acids in buffer solutions?

  They help maintain pH stability
• What happens when acids and bases react according to Bronsted-Lowry theory?

  Protons are exchanged between them
• How does water behave when an acid is added?

  It acts as a base by accepting protons
• What is the ionic product of water denoted as?

  Kw
• What does the ionic product of water indicate about its composition?

  Water exists in equilibrium with its ions
• Why can the concentration of water be considered constant in reactions?

  It is present in large excess
• What is the expression for Kw in terms of concentrations?

  Kw = [H+][OH-]
• What are the units of Kw?

  moles squared per dm to the minus six
• How does the dissociation of water compare to strong acids?

  Water dissociates very weakly
• What is the significance of equilibrium in acid-base reactions?

  It determines the direction of the reaction
• Why can the effects of water be ignored in certain calculations?

  Water has a constant value relative to ions
• What is the new constant derived from multiplying KC and the concentration of H2O?

  kW, the ionic product of water
• What is the value of kW at a given temperature?

  1 times 10 to the minus 14
• What are the units of kW?

  Moles squared DM to the minus six
• What is the relationship between H+ and OH- concentrations in pure water?

  They are equal in concentration
• How does the value of kW change?

  It changes with temperature
• What simplification can be made for the KW expression in pure water?

  KW equals H+ squared
• What does pH measure?

  The concentration of H+ ions in solution
• What is the pH scale range for acids, neutrals, and bases?

  0 (acidic) to 14 (basic)
• What is the equation to calculate pH?

  pH equals minus log base 10 concentration of H+
• How do you calculate the pH of hydrochloric acid with a concentration of 0.003 moles per cubic meter?

  pH equals minus log base 10 0.003
• What pH value indicates a strong acid like hydrochloric acid?

  A pH of 1.5
• How can the concentration of H+ ions be calculated from pH?

  H+ equals 10 to the minus pH
• What is the concentration of H+ ions in nitric acid with a pH of 1.7?

  0.019995 moles per cubic meter
• What is the assumption made for strong acids when calculating pH?

  They dissociate fully in solution
• How do you calculate the pH of 0.25 moles per cubic meter of hydrochloric acid?

  pH equals minus log 0.25
• What is a diprotic acid?

  An acid that produces two H+ ions per molecule
• How do you calculate the pH of sulfuric acid?

  Use twice the concentration for H+ ions
• What is the relationship between the concentration of H+ ions and the concentration of a diprotic acid?

  H+ concentration is twice that of the acid
• What is the pH of 0.25 moles per cubic meter of sulfuric acid?

  pH equals minus log 0.5