pH calculations Flashcards
1
Q
what is the equation for pH?
A
pH= -log{H+}
where [h+} is concentration in moldm-3
2
Q
What is the equation to calculate “hydrogen ion concentration from pH”
A
10 ^ -pH
3
Q
What is a monoprotic acid
A
An acid that dissociates giving off one proton per 1 molecule of acid.
this means that {H+} = {HA}
This means proton concentration is equal to acid concentration
4
Q
What is a diprotic acid?
A
when an acid dissociates, one molecule of that acid releases 2 protons.
so {H+}= 2{HA}
For diprotic questions multiply concertation by 2 THEN work out pH as normal
5
Q
What is the equation for Ka? ( for weak acids)
Ka is Acid dissociation constant
A
Ka= {H+] squared / {HA}
- the smaller the pKa value the stronger the acid
6
Q
pka=?
A
pKa= -log{ Ka}
Ka= 10^ -pKa
