Acids & Bases Flashcards
What is an acid and a base
Acid - Proton donor
Base - proton acceptor
how to calculate pH
-log [H+]
Describe dissociation of a strong vs weak acid
Strong acids - fully dissociate
Weak acids - do not fully dissociate
What’s the formula of Kw
[H+] [OH-]
What’s the value of Kw at 25C
10^-14
How do you find [H+] from a pH
10^-pH
What’s the definition of neutral
[H+] = [OH-]
How does concentration of H+ ions [H+] effect pH?
Increasing [H+] = decreased pH
Decreasing [H+] = increased pH
How do you find pH of pure water
when neutral Kw = [H+]^2
so [H+] = square root Kw
How does increasing the temperature of water effect pH
The dissociation of water is endothermic
- increasing the temp would push the equilibrium to the right
- so [H+] increases
- so pH decreases
how to get Ka from pKa
Ka = 10^-pKa
What’s the equation for weak acids dissociation
HA —> H+ + A-
HA is the weak acid
A- is the salt
How do you find pH of a weak acid on its own
Ka = [H+]^2 / [HA]
How do you work out pH of a DILUTED strong acid
- [H+] old x old volume/new volume
- pH -log
How do you work out pH DILUTED base
- [OH-] old x old volume/new volume
- [H+] = Kw/[OH-]
- pH -log