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pH quiz #1 Flashcards

pH quiz #1
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  • What is the definition of pH and how is it mathematically expressed?
    pH is a logarithmic measure of the hydrogen ion (H+) concentration in a solution, mathematically defined as pH = -log[H+].
  • How does the pH scale classify solutions as acidic, neutral, or basic?
    The pH scale classifies solutions as acidic if pH < 7, neutral if pH = 7, and basic if pH > 7.
  • What is the relationship between hydrogen ion concentration and hydroxide ion concentration in water at 25°C?
    At 25°C, the product of hydrogen ion concentration [H+] and hydroxide ion concentration [OH-] in water is always 1 x 10^-14 (kW).
  • Why is pH important in biochemistry?
    pH is important in biochemistry because many enzymes and biochemical processes are strongly affected by the concentration of protons (H+), influencing enzyme activity and biochemical reactions.
  • What happens to the pH value if the hydrogen ion concentration exceeds 1 M?
    If the hydrogen ion concentration exceeds 1 M, the pH value becomes negative, which is outside the typical 0-14 range.
  • How can you calculate the hydroxide ion concentration if you know the pH of a solution?
    First, calculate [H+] using [H+] = 10^-pH, then use [OH-] = kW / [H+], where kW = 1 x 10^-14 at 25°C.
  • Give an example of a common substance and its approximate pH value.
    Lemon juice is a common substance with an approximate pH value of 2, making it acidic.
  • Why are pH values outside the 0-14 range rare in biological systems?
    pH values outside the 0-14 range are rare in biological systems because such extreme H+ or OH- concentrations are uncommon and difficult to measure in biological contexts.
  • How is pH mathematically defined in relation to hydrogen ion concentration?
    pH is defined as the negative logarithm of the hydrogen ion concentration, or pH = -log[H+].
  • What happens to the pH value if the hydrogen ion concentration in a solution exceeds 1 M?
    If the hydrogen ion concentration exceeds 1 M, the pH value becomes negative, which is outside the typical 0-14 range.