CHEM 1011: Week 6: ACIDS & BASES Questions With Complete Solutions

BUFFERS What is a buffer? correct answer: - a buffer resists change in pH when a small amounts of acid or base are added to it. - any solution that contains equal amounts of a weak acid and its conjugate base will act as a buffer. What is acetic acid? correct answer: ethanoic acid. Gives vinegar its distinctive taste. What is buffer capacity? correct answer: the amount of acid or base that can be added to a buffer solution before a significant change in pH occurs What are some ways that a buffer can be prepared? correct answer: - mixing a weak acid with its conjugate base, e.g acetic acid and sodium acetate. - mixing a weak base with its conjugate acid, e.g. aqueous ammonia and ammonia chloride. - adding sufficient strong base to neutralise half the acid in the solution of weak acid. - adding sufficient strong acid to neutralise half the base in the solution of weak base. an acid is a substance that releases what? correct answer: H+ ions when dissolved in water :). a base is a substance that releases what? correct answer: OH- (hydroxide) when dissolved in water. what is pKa ? correct answer: - a measure of acid strength. - difference between ph and pka? correct answer: - pka is a measure of the strength of an acid in a solution.