Leacture 2 Flashcards
What are acid-base indicators?
Substances that change color in the presence of an acid or base, indicating the solution’s nature.
What are the two most widely used acid-base indicators?
Litmus paper and phenolphthalein.
Litmus paper is red for bases and blue for acids, neutral for both. Phenolphthalein is colorless in acid and pink in base.
What is titration?
A technique to determine the concentration of an acid or base by reacting it with a base or acid of known concentration.
What is the endpoint in titration?
The point at which the acid is exactly neutralized by the base, often indicated by a color change.
How is solution concentration measured?
In molarity (M), which is moles of solute per liter of solution.
What is the formula for molarity in solutions?
Molarity (M) = moles of solute / liters of solution.
Which equation is used to calculate titrations?
Molarity of acid × Volume of acid = Molarity of base × Volume of base.
What is the pH scale?
A measure of the concentration of H+ ions in a solution, indicating acidity or alkalinity.
How is the pH of a strong acid calculated?
pH = −log10[H+].
What is a buffer solution?
A solution that resists changes in pH when small amounts of acid or base are added.
What components are required in a buffer solution?
A weak acid and its conjugate base.
How does a buffer resist pH change?
By reacting with added H+ or OH− ions, preventing these ions from accumulating.
