Given:
Diprotic weak acid H2A:
Ka1 = 3.2 x 10^-6
Ka2 = 6.1 x 10^-9.
Concentration = 0.0650 m
Balanced chemical equation:
H2A ===> 2H+ + A2-
0.0650 0 0
-x 2x x
------------------------------
0.065 - x 2x x
ka1 = 3.2 x 10^-6 = [2x]^2 * [x] / (0.065 - x)
solve for x and determine the concentration at equilibrium.
A chemical reaction that has a positive g is best described as endergonic.
The pH of a buffer solution containing acid of pKa 7.5 will be 8.1.
The pH of a solution indicates its acidity or basicity. A pH below 7 is acidic, while pH above 7 is basic. 7 is considered as the neutral value.
A buffer is a solution that has the ability to resist the change in pH when an acid or a base is added to it. The natural example of buffer is blood.
According to the question, pKa of acid = 7.5
If concentration of base is x then, concentration of acid will be x/4.
According to the Henderson–Hasselbalch equation,
pH = pKa + log [A⁻] / [HA]
pH = 7.5 + log [
]
pH = 7.5 + log 4 ⇒ 7.5 + 0.602
pH = 8.1
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Answer:
/D/ either absorbs or releases energy
Explanation:
During a phase change energy is either absorbed or released.
A phase change is a reversible process which occurs when a substance changes is its state from one form to another.
Phase changes are used to delineate physical changes.
- A phase diagram provides a graphic representation of the change.
- The diagram can be 2 dimensional or 3 dimensional.
