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pH and pOH quiz #7

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Terms in this set (36)

  • What is the pOH of the solution? Round to the nearest hundredth.
    pOH = 14 - pH; round to two decimal places.
  • The acid dissociation constant, Ka, of acetic acid is 1.8 x 10^-5. What is the pKa of this acid?
    pKa = -log(1.8 x 10^-5) ≈ 4.74
  • What is the pH of a 0.300 M solution of aniline (C6H5NH2, Kb = 4.3 x 10^-10)?
    Use Kb and ICE table to solve for [OH–], then pOH and pH.
  • When an acid is dissolved in water, how does it change the solution's pH?
    It lowers the pH.
  • What is the pH of a 0.0620 M solution of hydrocyanic acid, HCN (Ka = 4.9 x 10^-10)?
    Use ICE table and Ka to solve for [H+], then pH.
  • How would removing water from the bloodstream affect the pH of the blood?
    It could increase the concentration of ions, potentially altering pH.
  • At what pH will enzymes in human blood function best?
    Around pH 7.4.
  • Assuming equal concentrations, arrange these solutions by pH: strong acid, weak acid, strong base, weak base.
    Strong base > weak base > weak acid > strong acid.
  • Calculate either [H3O+] or [OH–] given pH or pOH.
    [H3O+] = 10^-pH; [OH–] = 10^-pOH.
  • In an aqueous solution at 25°C, if [H3O+] = 2.4 x 10^-5 M, then [OH–] is:
    [OH–] = Kw / [H3O+] = 1 x 10^-14 / 2.4 x 10^-5 ≈ 4.17 x 10^-10 M
  • The pH of a solution is defined as
    The negative logarithm of the hydrogen ion concentration.
  • Determine the pH of a 0.62 M NH4NO3 solution at 25°C. The Kb for NH3 is 1.76 x 10^-5.
    Calculate using Ka for NH4+ and ICE table.
  • The pOH of a 0.300 M solution of NaOH is
    pOH = -log(0.300) ≈ 0.52
  • A decrease in pH will increase the solubility of CaCO3 because
    More H+ reacts with CO3^2–, shifting equilibrium and increasing solubility.
  • Calculate the pH when 10.0 mL of 0.150 M KOH is mixed with 20.0 mL of 0.300 M HBrO (Ka = 2.5 x 10^-6)
    Calculate moles, find excess, determine pH.
  • The pH of a 0.0040 M solution of HNO3 is
    pH = -log(0.0040) ≈ 2.40
  • An aqueous solution is neutral when
    [H+] = [OH–]
  • Calculate the pH when 50.0 mL of 0.150 M KOH is mixed with 20.0 mL of 0.300 M HBrO (Ka = 2.5 x 10^-6)
    Calculate moles, find excess, determine pH.
  • A solution has a pH of 13.20. We can conclude that
    It is strongly basic.
  • The pOH of pure water at 40°C is 6.8.
    At 40°C, Kw is higher, so pOH is lower than 7.
  • How is the pH of a solution defined?
    The pH of a solution is defined as the negative logarithm of the hydrogen ion (H+) concentration: pH = -log[H+].
  • What happens to the pH of a solution when acids are added?
    When acids are added to a solution, the pH decreases.
  • If vinegar has a pH of 2, what does this indicate about its acidity?
    A pH of 2 indicates that vinegar is a strong acid.
  • What does it mean if a solution has a pH of 7?
    A solution with a pH of 7 is neutral at 25°C.
  • What acid-base imbalance can be caused by diarrhea?
    Diarrhea can cause metabolic acidosis, which is an acid-base imbalance where the body becomes more acidic.
  • What is considered a neutral pH at 25°C?
    A neutral pH at 25°C is 7.
  • At what pH do pathogens grow very slowly?
    Pathogens grow very slowly at low pH (acidic conditions) or very high pH (basic conditions), but most slowly at extreme pH values far from neutral.
  • What is the typical pH range of phenolic disinfectants?
    Phenolic disinfectants typically have a basic pH, meaning their pH is greater than 7.
  • What is the mathematical relationship between pH and pOH?
    The relationship between pH and pOH is given by the equation: pH + pOH = 14 (at 25°C).
  • What type of solution has a pH of 13?
    A solution with a pH of 13 is strongly basic.
  • Which formula represents the concentration of hydrogen ions in an aqueous solution?
    The concentration of hydrogen ions in an aqueous solution can be represented as [H+] = 10^(-pH).
  • How are pH and pOH related in aqueous solutions?
    In aqueous solutions at 25°C, pH and pOH are related by the equation: pH + pOH = 14.
  • How is the pH of a solution related to the concentration of H3O+ ions?
    The pH of a solution is related to the concentration of H3O+ ions by the equation: pH = -log[H3O+].
  • If the pH of a solution is 4, what is its pOH at 25°C?
    If the pH is 4, the pOH is 10, since pH + pOH = 14.
  • What does it mean for a solution to be acidic, basic, or neutral in terms of pH?
    A solution is acidic if pH < 7, neutral if pH = 7, and basic if pH > 7 (at 25°C).
  • What is the ion product constant for water (Kw) at 25°C, and how does it relate to [H+] and [OH-]?
    At 25°C, the ion product constant for water (Kw) is 1.0 × 10⁻¹⁴, and Kw = [H+][OH-].