Acids And Bases Flashcards
What is an acid
A proton donor
What is a base
A proton acceptor
What is kw
KW = [H+] [OH-]
What is the equation for PH
-log [H+]
What’s the equation for [H+]
10 to the minus pH
What’s the equation for ka and when is it used
Ka = [H+] [A-]
[HA]
Used when finding conc or pH of weak acids and bases
Larger Ka means stronger weak acid
What assumptions are made when using Ka
HA of equilibrium is equal to HA of initial as ionisation so small it’s approximately the same
H+ = A- as ionisation of water negligible so any H+ created by water can be ignored
What is the equation for pKa
Pka- -log (ka)
What’s the equation for ka in relation to pka
Ka = 10 to the minus pka
How is a buffer solution made
By mixing a weak acid or base with one of its salts
How to work out pH of a buffer solution
Use Ka formula assuming A- is the initial salt conc and HA is the initial conc
How to work out pH of a buffer solution after adding acid
Convert cm3 to dm3
Calc moles of acid added
Calc moles of HA nd basic ion using an ice table
Calc conc of those
Put into ka
Calc pH
How to work out pH of a buffer after adding a base
Convert cm3 to dm3
Calc moles of acid added
Calc moles of HA nd basic ion using an ice table
Calc conc of those
Put into ka
Calc pH
