5.1.10: Acid-base reactions and Ka Flashcards
What is an alkali?
A base that dissolves in water forming OH- (aq) ions
What is neutralisation?
A chemical reaction in which an acid and a base react together to produce salt and water.
What is a strong acid?
An acid that completely dissociates in solution.
What is a weak acid?
An acid that partially dissociates in solution.
The acid dissociation constant, Ka, of an acid HA is defined as…
Ka= [H+(aq)][A-(aq] / [HA(aq)]
What is the formula for pKa?
pKa= -log10(Ka)
What is the formula for Ka?
Ka= 10^-pKa
Write the ionic equation when aqueous acids (e.g.HCl) react with solid carbonates (e.g. CaCO3)
look in book
Write the ionic equation when aqueous acids (e.g.HCl) react with aqueous carbonates (e.g. Na2CO3)
look in book
see other ionic equations in the book. (bases, alkalis and metals)
look in book
What are the chemical formulas for the following acids?
Hydrobromic acid
Hydriodic acid
Chloric(VII) (perchloric) acid
HBr
HI
HClO4
An eqm. is set up when ethanoic acid dissociates in water:
CH3COOH(aq) ↔ H+(aq) +CH3COO-(aq)
Where does the equilibrium position lie?
- To the left.
- Only a small conc. of dissociated ions, compared with the conc. of undissociated CH3COOH(aq).
What does Ka tell us?
The extent of acid dissociation.
- A large Ka value indicates a large extent of dissociation (the acid is strong).
- A small Ka value indicates a small extent of dissociation (the acid is weak)
What are the units of Ka?
moldm-3
A low value of Ka matches a ___ value of pKa.
A high value of Ka matches a ___ value of pKa.
high
low
