If a weak acid is 25% deprotonated at ph 4, what is the pka?if a weak acid is 25% deprotonated at ph 4, what is the pka?
2 answers:
4.48
pH=pKa+log([A-/HA])
25% deprotonated tells us that A- is .25 and that the rest (75% is protonated) thats .75.
4 = pKa + log
4 - log = pKa
4.48=pKa
pH=pKa+log([A-/HA])
25% deprotonated tells us that A- is .25 and that the rest (75% is protonated) thats .75.
4 = pKa + log
4 - log
4.48=pKa
Answer:
pKa = 4.5
Explanation:
The weak acid can be represented by the general formula, HA and the dissociation equilibrium given as:
where HA = protonated form
A- = deprotonated form
The Henderson-Hasselbalch equation relates the pH of a solution to the ratio of the concentrations of HA and A- as;
It is given that:
% deprotonated i.e. A- = 25%
Therefore, %protonated i.e. HA = 100 -25 = 75%
pH = 4
Based on equation (1)
pKa = 4.477 i.e. around 4.5
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Answer:
The volume is 4.13793 L
Explanation:
Density is a quantity that expresses the relationship between the mass and the volume of a body, so it is defined as the quotient between the mass and the volume of a body:
Density is a characteristic property of every body or substance.
The most commonly used units of density are or
for solids, and
or
for liquids and gases.
In this case, you know:
- density= 0.87
- mass= 3.6 kg= 3,600 g (being 1 kg=1,000 g)
- volume= ?
Replacing:
Solving:
volume= 4,137.93 mL
Being 1,000 mL=1 L, then volume= 4,137.93 mL= 4.13793 L
<u><em>The volume is 4.13793 L</em></u>