MAP 6

• What is a Brønsted acid?

  A species that can donate a proton
• How does hydrogen chloride (HCl) act as a Brønsted acid?

  It loses a proton to form H and Cl ions
• What is a Brønsted base?

  A species that can accept a proton
• How does a hydroxide ion (OH⁻) act as a Brønsted base?

  It accepts a proton to form water
• What occurs in an equilibrium reaction?

  Products form at the same rate as reactants
• What species are present when equilibrium is established with ethanoic acid?

  CH₃COOH, H₂O, CH₃COO⁻, and H₃O⁺ ions
• What are conjugate acid-base pairs?

  Two species differing by one proton
• How are the reactant CH₃COOH and product CH₃COO⁻ linked?

  By the transfer of a proton from acid
• What is the formula for pH?

  pH = -log[H⁺]
• How can the concentration of H⁺ be calculated from pH?

  [H⁺] = 10^(-pH)
• What does the pH scale represent?

  A logarithmic scale with base 10
• How much more acidic is pH 5 compared to pH 6?

  10 times more acidic
• To how many decimal places are pH values usually given?

  Two decimal places
• What are the steps to calculate pH from hydrogen concentration?

  1. Use the formula pH = -log[H⁺]
  2. Substitute the concentration of H⁺ into the formula
  3. Calculate the pH value

  
• What is the pH when the hydrogen concentration is $1.60 \times 10^{-4} \text{ mol dm}^{-3}$?


  pH = 3.80
• How do you find hydrogen concentration from pH of 3.10?

  [H⁺] = $7.94 \times 10^{-4} \text{ mol dm}^{-3}$
• What is the pH of a solution after mixing 10.0 cm³ of pH 1.0 acid with 990.0 cm³ of water?

  pH = 3
• What characterizes strong acids in solution?

  They are completely ionized in solution
• How does the concentration of hydrogen ions relate to strong acids?

  [H⁺] equals the concentration of the acid

  
• What is a dibasic acid?

  An acid with two replaceable protons
• How does sulfuric acid ionization occur?

  In two steps with equilibrium in the second
• What do electrochemical cells generate from spontaneous redox reactions?

  Electricity
• What is the pH of 0.01 mol dm⁻³ hydrochloric acid?

  pH = 2.00
• What is the reaction equation for zinc and copper sulfate?

  Zn (s) + CuSO₄ (aq) → Cu (s) + ZnSO₄ (aq)
• How are electrons transferred in an electrochemical cell?

  Electrons are transferred through a built cell
• What is a half cell in an electrochemical cell?

  Each part of the cell
• Why is the measured pH of 0.1 mol dm⁻³ sulfuric acid about 0.98?

  It indicates it is not fully ionized
• What happens when a metal is dipped into a solution of its own ions?

  An equilibrium is established
• What is the role of the metal strip in a half cell?

  It acts as an electrode
• What are the steps of sulfuric acid ionization?

  1. H₂SO₄ → HSO₄⁻ + H⁺ (first step)
  2. HSO₄⁻ ⇌ SO₄²⁻ + H⁺ (second step)
  3. Equilibrium is established in the second step
• What determines the potential difference in a half cell?

  The position of equilibrium
• What is electrode potential?

  The potential difference between rod and solution
• What occurs when Zn atoms deposit electrons on the rod?

  Negative charge accumulates on the rod
• What happens when Zn²⁺ ions accept electrons from the rod?

  Positive charge accumulates on the rod
• What is the pH of 0.01 mol dm^-3 hydrochloric acid?

  2.00
• What factors affect the potential difference in a half cell?

  Nature and concentration of ions, electrode type, temperature
• How is the pH of hydrochloric acid calculated?

  pH = -log[H⁺]
• What does a more positive electrode potential indicate?

  Higher likelihood of reduction
• What does a more negative electrode potential suggest?

  Lower likelihood of reduction
• What is the pH of 0.1 mol dm^-3 sulfuric acid?

  About 0.98