3.1.12.2 pH and Kw

• The pH scale ranges from 0 to 14.

  True
• What does Kw quantify?

  Water equilibrium
• If [H+] increases, what happens to [OH-]?

  It decreases
• What is the value of Kw at 25°C?

  1.0 x 10^-14
• What is the equation relating pH, pOH, and Kw?

  pH + pOH = 14
• What does pOH measure in a solution?

  Alkalinity
• What is the formula to calculate pH from hydrogen ion concentration [H+]?

  pH = -log10[H+]
• What is the pH of pure water?

  7
• Match the term with its definition:

  pH ↔️ Measures acidity or alkalinity

  pOH ↔️ Measures alkalinity

  Kw ↔️ Ion product constant for water
• What is the formula to calculate pOH from hydroxide ion concentration [OH-]?

  pOH = -log10[OH-]
• The relationship between pH and pOH is given by the equation: pH + pOH = 14
• Match the variable in the Arrhenius equation with its meaning:

  Kw(T) ↔️ Ion product constant at temperature T

  Kw(25°C) ↔️ Ion product constant at 25°C

  ΔH° ↔️ Standard enthalpy change

  R ↔️ Ideal gas constant

  T ↔️ Temperature in Kelvin
• The Kw of water is used to determine the pH of a solution and the relative concentrations of H+ and OH-
• Both pH and Kw are essential for understanding and optimizing chemical reactions.


  True
• What is the value of Kw at 25°C?

  1.0 x 10^-14
• The value of Kw is [H+][OH-] = 1.0 x 10^-14
• What is the formula to calculate pH from [H+]?

  pH = -log10[H+]
• pOH is calculated using the formula: pOH = -log10[OH-], where [OH-] is the hydroxide ion concentration
• Kw at 35°C is approximately 1.53 x 10^-14
• What does pH indicate in a solution?

  Acidity or alkalinity
• Match the condition with its corresponding pH and pOH ranges:

  Acidic ↔️ pH < 7, pOH > 7

  Neutral ↔️ pH = 7, pOH = 7

  Alkaline ↔️ pH > 7, pOH < 7
• A solution with a [H+] of 1.0 x 10^-3 M has a pH of 3.
• What is the pH of a solution with [H+] = 1.0 x 10^-3 M?

  3
• What is the modified Arrhenius equation used for in the context of Kw calculations?

  Calculating Kw at different temperatures
• Match the pH value with the corresponding condition:

  pH < 7 ↔️ Acidic

  pH = 7 ↔️ Neutral

  pH > 7 ↔️ Alkaline
• At 25°C, the value of Kw is 1.0 x 10^-14.


  True
• The pH scale ranges from 0 to 14.
• In pure water, [H+] = [OH-].


  True
• Match the condition with the corresponding pH and pOH values:

  Neutral ↔️ pH = 7, pOH = 7

  Acidic ↔️ pH < 7, pOH > 7

  Alkaline ↔️ pH > 7, pOH < 7
• Kw is the ion product constant for water, defined as Kw = 1.0 x 10^-14
• The pH formula tells us how acidic or alkaline a solution is based on the concentration of hydrogen ions
• What is the numerical value of Kw at 25°C?

  1.0 x 10^-14
• What is the formula to calculate pH from hydrogen ion concentration [H+]?

  pH = -log10[H+]
• What equation relates pH, pOH, and Kw?

  pH + pOH = 14
• In acidic conditions, pH is less than 7 and pOH is greater than 7.

  True
• What does pH indicate about a solution?

  Acidity or alkalinity
• The pH scale ranges from 0 to 14, where 7 is neutral.


  True
• What does pH measure?

  Acidity or alkalinity
• If [H+] increases, [OH-] must decrease to maintain Kw.


  True
• Match the condition with its corresponding pH range:

  Neutral ↔️ pH = 7

  Acidic ↔️ pH < 7

  Alkaline ↔️ pH > 7