Flashcards on The pH scale and indicators
The pH Scale and Indicators: A Comprehensive Student Guide
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pH stupnice
31 cards
Card 1
Question: What does the term "pH" stand for?
Answer: Potential of hydrogen or power of hydrogen.
Card 2
Question: What does pH refer to?
Answer: The concentration of hydrogen ions in a solution.
Card 3
Question: Describe the self-ionization process of water.
Answer: A small fraction of water molecules dissociate into hydrogen ions (H⁺) and hydroxide ions (OH⁻), represented by the equilibrium reaction: H₂O ⇌ H⁺ + O
Card 4
Question: What are the concentrations of H⁺ and OH⁻ in pure water at 25 °C?
Answer: Both are 1.0 × 10⁻⁷ moles per liter (mol/L).
Card 5
Question: What happens to the concentration of H⁺ ions when an acid is added to water?
Answer: It increases the concentration of H⁺ ions.
Card 6
Question: What happens to the concentration of OH⁻ ions and subsequently H⁺ ions when a base is added to water?
Answer: It increases the concentration of OH⁻ ions, which in turn reduces the concentration of H⁺ ions due to the equilibrium.
Card 7
Question: What is the ion product of water?
Answer: It is an equilibrium constant for the self-ionization of water, denoted as Kw.
Card 8
Question: What is the value of Kw at 25 °C?
Answer: 1.0 × 10⁻¹⁴.
Card 9
Question: How is Kw defined?
Answer: Kw = [H⁺] · [OH⁻] = 1.0 × 10⁻¹⁴ (mol/L)².
Card 10
Question: What is the implication of the Kw relationship on the presence of H⁺ and OH⁻ ions in any aqueous solution?
Answer: Both H⁺ and OH⁻ ions are always present.