From Paper 1: Advanced Inorganic and Physical Chemistry
9(a)3 marks
Calculate the pH of 0.20 mol dm⁻³ propanoic acid (Ka = 1.35 × 10⁻⁵ mol dm⁻³).
From Paper 1: Advanced Inorganic and Physical Chemistry
9(b)3 marks
A buffer contains 0.20 mol dm⁻³ propanoic acid and 0.30 mol dm⁻³ sodium propanoate. Calculate its pH.
From Paper 1: Advanced Inorganic and Physical Chemistry
9(c)*6 marks
Explain how this buffer resists changes in pH when small amounts of acid or alkali are added, and why it would not work after large additions.
From Paper 3: General and Practical Principles in Chemistry
1(a)4 marks
A student titrated 25.0 cm³ of sodium hydroxide with 0.100 mol dm⁻³ hydrochloric acid. Her titres were 22.45, 22.10, 22.15 and 22.20 cm³. Calculate the mean titre using concordant results and the concentration of the sodium hydroxide.
From Paper 3: General and Practical Principles in Chemistry
1(c)2 marks
Explain why methyl orange or phenolphthalein would both be suitable for this titration.
From Paper 3: General and Practical Principles in Chemistry
11(f)1 mark
Which of these has the lowest pH at the same concentration?
From Paper 3: General and Practical Principles in Chemistry
135 marks
Describe how to determine the acid dissociation constant, Ka, of a weak acid using a pH meter and sodium hydroxide solution.
Score 0 / 24 · 0 of 7 marked
This paper is written by Plasmo in the style of the Edexcel A-Level Chemistry exam. It is not a past paper and is not produced or endorsed by the exam board.