All Questions
32
questions
3
votes
0
answers
27
views
Non-binding buffer at pKa of roughly 6 that dissolves in ethanol?
I'm trying to find a proper buffer for my experiment, which I'd appreciate some suggestions on. I have a solution in which I want to measure the concentration of magnesium ions using a fluorescent ...
- 31
3
votes
0
answers
38
views
Assessing stability of protein used for interaction experiments after changing buffer from tris to HEPES
I have a protein with a theoretical $\mathrm{pI}~9.0$ currently stored in $\pu{25 mM}$ tris and $\pu{250 mM}$ $\ce{NaCl}$ $(\mathrm{pH}~8)$ at $\pu{−80 °C}.$ I need to do experiments in HEPES at $\...
- 488
-2
votes
1
answer
92
views
Calculate the pH of a buffered solution after adding strong acid [closed]
Calculate the pH of a solution formed by the addition of $0.0020$ moles of $\ce{HCl}$ to $\pu{100.0 mL}$ of $\pu{0.200 M}$ $\ce{CH3NH2}$/ $\ce{0.100 M CH3NH3Cl}$.
$K_\mathrm{b}(\ce{CH3NH2})=4.4\times ...
- 33
-1
votes
1
answer
148
views
pH and degree of dissociation of drugs
I have a doubt, i hope not so stupid.
Suppose we consider a buffer solution of acetic acid/acetate at pH = pKa = 4.76 and we add aspirin (pKa = 3.5): given that the pH of the solution is higher than ...
- 127
3
votes
0
answers
78
views
Measuring [A-]/[HA-] with Buffer and Indicator
I'm very confused on how to calculate the [A-]/[HA] value, given the fact that my dilution series uses buffers at various pH values with the same indicator (supplied at the same concentration to each ...
0
votes
1
answer
76
views
Why doesn't the volume of NH3 = 325 ml in this problem? [closed]
I'm struggling with the problem below, and don't understand why
A buffer solution with pH = 9.0 is to be prepared from a 0.2 M ammonia
solution and a 0.15 M $\ce{HCl}$ solution. The sum of the molar
...
- 423
0
votes
0
answers
40
views
Calculating acid volumes needed
I collect water quality samples used for irrigation. The samples are sent to a lab to measure $\ce{Ca^{2+}, Mg^{2+}, CO3^{2-}, HCO3^-}$, pH, and total dissolved solids.
I need to use acid to prevent ...
- 21
0
votes
1
answer
1k
views
A method to create NH3-NH4Cl buffer solution using titration method
My aim is to create a basic buffer solution.
I know that to create a basic buffer solution, we need a strong acid and weak base. In my case I have chosen $\ce{NH3}$ and $\ce{NH4Cl}$.
Using titration, ...
-3
votes
1
answer
83
views
pH calculation of a mixure containing 2 strong acids and a buffer mixture
Calculate the pH of a mixtureof 10 mL 0,1 M HCl ; 5 mL 0,1 M HNO3 ; 10 mL 0,2 M HAc ; 15 mL 0,4 M NaAc.
My understanding was that I have to find the [H+] by:
finding the concentration of the products ...
- 11
0
votes
0
answers
65
views
How to find pH for acetate buffer?
Calculate the pH of the solution that results when $\pu{40.0 mL}$ of $\pu{0.100 M}$ $\ce{CH3COOH}$ is mixed with $\pu{30.0 mL}$ of $\pu{0.200 M}$ $\ce{NaCH3COO}.$ $K_\mathrm{a}(\ce{CH3COOH}) = \pu{1....
- 27
0
votes
0
answers
72
views
Finding dissolved amount of base from pH and solubility product
Calculate the amount of $\ce{Mg(OH)2}$ which is solubilized in $\pu{1.25 L}$ of a buffered solution at $\mathrm{pH} = 9.5$. $(K_\mathrm{sp}(\ce{Mg(OH)2}) = \pu{5.61E-12})$.
From $\mathrm{pH}$ I ...
- 109
1
vote
0
answers
57
views
Can addition of a "neutral" salt like NaCl assist pH test strip measurement accuracy in low ionic strength/poorly buffered solutions?
After a web-search, it seems ISAs (Ionic Strength Adjusters) are offered commercially to assist pH electrode/probe measurements. Presumably meant to increase conductivity (without affecting pH ...
- 129
0
votes
0
answers
137
views
How to estimate the pH of multi-component buffer (phosphate buffer in equilibrium with CO2 rich atmosphere)?
I wonder how the pH of buffer solution can be estimated if buffer consists of several systems in equilibrium to the gas phase. For example, (based on growth medium for one of the bacteria) buffer ...
- 151
0
votes
1
answer
766
views
pH of PBS after adding acetic acid
Why is there a need for pH adjustment below ? Can pH go below 4.3 after adding acetic acid to PBS ?
“First prepare stock solution consisting of 50 ml of 10× PBS (pH 7.4), 12.5 ml of 80% glycerol, and ...
- 103
-1
votes
1
answer
732
views
Prepairing a Sodium Acetate buffer - Meaning of molarity
We have instructions to prepare a "50 mM Sodium Acetate, pH 5 solution". I am not entirely sure what does the molarity refer to in this case. Does it mean:
Add Sodium Acetate salt up to 50 ...
- 119