Acid/base Equilibria Flashcards
What 2 assumptions are made when finding the pH of a weak acid?
- The initial conc. = conc. at equilibrium
2. [RCOO-] = [H+] Therefore numerator simplifies to [H+]2
What is the equation for the ionic product of water?
Kw= [H+][OH-]
What pH does the vertical portion for a strong acid/strong base titration curve cover?
pH 3-11
What is the equivalence point of a strong acid/strong base titration curve?
pH= 7
What is the pH range of the vertical section of a strong acid/weak base titration curve?
pH 3-7
Where is the buffered region of a strong acid/weak base titration curve?
pH 9-11
Give two equations to show the buffer effect of a weak base.
- NH4+ + OH- = NH3 + H2O
2. NH3 + H+ = NH4+
What is the pH range of the vertical section of a weak acid/strong base titration curve?
pH 7-11
Where is the buffered region of a weak acid/strong base titration curve?
pH 5
Give two equations to show the buffer effect of a weak acid
- CH3COOH- + H+ = CH3COOH
2. CH3COOH + OH- = CH3COO- + H2O
Where must the pH range of an indicator lie in order for it to be suitable for a certain acid/base titration?
Well within the vertical section of the acid/base titration curve
Give the definition of a buffer solution.
A buffer solution is one that minimises small changes in pH. A buffer solution consists of a weak acid and one of its salts (conjugate base).
Name three indicators.
- Bromothymol Blue
- Phenolphthalein
- Methyl Orange
What is [H+] in terms of pH?
[H+]= 10*-pH
