Linked Questions
29 questions linked to/from How to set up equation for buffer reaction?
4
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Am I understanding buffering capacity against strong acid/base correctly?
I just want to make sure I'm understanding buffering capacity correctly.
I've been working on this problem:
Suppose you have an acetic acid buffer, $\mathrm{p}K_\mathrm{a} = 4.74$, at the ...
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10
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2
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What are the limitations of the Hendersson-Hasselbalch equation?
Our instructor told us that prior to the equivalence point, the $\mathrm{pH}$ of a solution is dependent on the HH equation. However, when I tried practicing for polyprotic acid titration, I came upon ...
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2
answers
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Are the best buffers those that are in a 1:1 ratio with its conjugate acid/base?
I wanted to comment this, but I don't have enough reputation, so I just made this a question. I know that buffers and their conjugate base/acid must exist in similar amounts for the buffer to be ...
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1
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Finding the pH value of HF [closed]
Find the pH value of HF.
$pH = -\log[H+]$ for strong acids
$pOH = -\log[OH-]$ for strong bases
$pH = 1/2(pKa - \log C)$ for weak acid
$pOH = 1/2(pKb - \log C)$ for weak base
HF is weak acid so $...
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1
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Confusion regarding calculating the pH of a salt of weak acid and weak base
I need to calculate the $\mathrm{pH}$ of a salt of weak acid and weak base in an aqueous solution.
Method I used for calculation
For a salt of a weak acid and a weak base (assuming complete ...
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2
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Calculate pH of a mixture of a strong base and acid. Knowing only the pH, wt/v%, and volume of both solution. [closed]
Title explains all. I have been stuck on this for an hour and for some reason cannot understand it. I have tried to do an ICE table but get stuck halfway as I do not know whether I would use the w/v ...
2
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1
answer
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Why does pH of a buffer solution change according to Henderson–Hasselbalch equation? [closed]
If I add a little amount of acid or base to a buffer solution, the pH of the buffer won't change. That's what the diagramatic mechanism tells us.
But according to Henderson–Hasselbalch equation, the $...
-1
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2
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How to find the ionization constant of an unknown weak acid?
A $\pu{0.45 M}$ solution of a weak acid, $\ce{HX}$, has a $\pu{pH}$ of $4.5$. What is the ionization constant, $K_a$, of the acid?
$\ce{[HX]}$ is already given as $\pu{0.45 M}$.
$\ce{[H+]}$ is given ...
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3
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1
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Accurate method to calculate the pH of a salt from a weak acid and weak base
Can someone help me with this?
The problem is as follows:
Find the $\mathrm{pH}$ of $\pu{1M}$ solution of $\ce{NH4CN}$. Their respective
hydrolysis constants are:
$K_h = 5.6\times 10^{-10}$
...
-1
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1
answer
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Why does a weak base, which is also a salt, dissociate completely in water? [closed]
I'm answering a problem where $\ce{KOH}$ and $\ce{KOAc}$ dissociate nearly as much as each other in separate aqueous solutions at equal concentrations. The problem essentially assumed both completely ...
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1
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1
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397
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Calculate the pH of buffer solution
PROBLEM: A solution was prepared by mixing $\pu{25.00 mL}$ of $\ce{NaOH}$ $\pu{(c = 1mol/L)}$ and $\pu{10.00 mL}$ of acetic acid $\pu{(c = 2.5 mol/L)}$ in water to give $\pu{250 mL}$ of solution.
...
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4
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A simple equilibrium problem
Take the following simple equilibrium:
$$\ce{CH3COOH + H2O <=> H3O+ + CH3COO-}$$
Ethanoic acid will act as a typical Brønsted-Lowry acid and donate a proton to water, forming a conjugate acid-...
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3
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1
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What happens when you add a weak acid to a solution buffered at a pH of 8.0?
There are a lot of textbook examples showing what happens to the pH of a buffered solution when you add strong acids and strong bases. Searching for an example calculation where you add weak acids or ...
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-3
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1
answer
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When pH > pKa and when pH < pKa and the effectiveness of buffer solutions
I understand that when $\mathrm{pH}= \mathrm{p}K_\mathrm{a}$, the buffer solution will be at its maximum capacity, and there will be equal concentrations of the acid/conjugate acid and the base/...
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1
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Why are some weak acid equilibrium approximations invalid in very dilute solutions?
Using two approximations for the dissociation of a weak acid, we can write
$$K_\mathrm{a}= \frac{[\ce{H+(aq)}]^2}{[\ce{HA(aq)}]}$$
One of these two approximations we use is that the concentration of ...
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