Stands for Potential of Hydrogen and is a measure of how acidic or base an aqueous substance is.

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Impossible pH For Aqueous Weak Acid Solution

An aqueous solution of $HCl$ has a $pH$ of $0.00$ if $[H^{+}] = 1.00 \; M$. I tried to see if an aqueous solution of acetic acid could have a $pH$ of $0.00$, given that its $K_a$ value is $1.8 \times ...
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Carbonic acid-hydrogencarbonate buffer system pH calculation?

I am learning about the pH of buffer solutions, and am slightly confused by my text book's calculation. For the blood's buffer system of carbonic acid and hydrogencarbonate ions as the conjugate case, ...
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48 views

Why is ionic strength (mu) calculated differently for these 2 examples?

In the following examples; I don't understand why $\ce{Na_3PO_4}$ is a much more complicated process when calculating $\mu$ compared to $\ce{NaH_2PO_4}$ and $\ce{Na_2HPO_4}$. Specifically, I don't ...
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Henderson Hasselbach Equation

So will the hasselbach equation be able to calculate the pH when you have an acidic solution and you add a basic solution? Will that be possible or should you must add only add an acid to calculate ...
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How to report pH values?

I have measured the pH in the water-soluble fraction of a powder. I weighed in a certain amount of powder and a certain amount of water, and extracted the water-soluble fraction. I then measured the ...
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67 views

How do I know that an acid and conjugate base are present in equimolar amounts?

Acetylsalicylic acid is a molecule in several popular drugs such as Magnyl and aspirin. Its pKa is 3.5, and I'm about to calculate the pH of a 0.010 M solution of acetylsalicylic acid. I've read up ...
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36 views

Calculating charge of amino acids (am I doing it right?)

Please consider this picture of a peptide chain: I've done some examining on the different amino acids and concluded that the chain is as follows: Lys-Leu-Gly-Ser-Citrullin (variant of arginine). ...
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Which pH indicator will give a dramatic color change with small changes in the amount of carbon dioxide dissolved in water?

I want to do a demonstration for students where they take a capped syringe and change the volume above a solution of seltzer water. The amount of carbon dioxide dissolved will vary, hopefully ...
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How can pKas differ across similar protons of the same atom?

For example, citric acid has three acidic protons, all of which are carboxylic acids. Despite being part of the same functional groups, they all have very different pKas. Why (and how?) is this?
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Can a negative pH exist? [duplicate]

I am programming a small model to simulate diffusion of $\ce{H+}$ ions in human tissue. It's quite a simplistic model based on a naive algorithm, and I'm mostly doing it to familiarize with the ...
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27 views

Carbonate + acid reactions - How to recognize these type of reactions?

So I've got $$\ce{CaCO_3 + HCl \rightarrow CO_2 + H_2 O + CaCl_2}$$ I'm wondering how I can recognize these types of reactions? I know that when I mix an acid and a base I get salt and water but in ...
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91 views

pH Curves for Titrations

Why does the pH rapidly increase near the equivalence point during--why does the slope of the graph of a pH curve sharply increase around this area?
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Why is it that weak bases usually contain a Nitrogen?

Why do weak bases usually contain a nitrogen, I know there are two electrons on top for a bond of H but why is it mostly nitrogen? I know there are other elemental bases too but why do I keep seeing ...
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434 views

What's the pH of Vinegar when it generally contains 5% Acetic acid?

Vinegar generally contains 5% Acetic acid. We would expect the pH of vinegar to be approximately: a. 0 b. 3 c. 7 d. 9 e. 12 I don't have the key for this question, so I ...
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32 views

What is the S2- in 0.10 M hydrogen sulfide?

I found this question in one of the problem sets and I decided to try it, I keep getting 9.1E-8 as the answer and I thought this since this is a diprotic acid and I made two equations and I keep ...
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41 views

How to calculate the pH of a citric acid solution after adding magnesium oxide? [closed]

$4.03~\mathrm{g}$ ($0.100~\mathrm{mol}$) of magnesium oxide is added to $100~\mathrm{mL}$ of a saturated ($4.00~\mathrm{mol\cdot L^{–1}}$) solution of citric acid. Calculate the pH of the resulting ...
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44 views

What ratio of bicarb to vinegar do I need in order for the result to be ph neutral?

This question stems from the one I just asked over at cooking where my recipe tasted decidedly off because the pH was wrong. The recipe called for 16g bicarb of soda and 15g of vinegar (mine was 5% ...
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34 views

Find amount of Acid and Base required to make buffer

I am wondering if it is possible to know exact amount of acid and base that we can put in together to make a buffer. I want to make a 0.05M Extraction buffer using Disodium Hydrogen Phosphate and ...
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53 views

Are all strong acids the same strength?

Since the six strong acids dissociate completely into their ions, and the reaction goes to completion, does this mean that acids such as $\ce{HI}$ and $\ce{HCl}$ have the same acidic strength? I know ...
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I have 100mg of a proteinase K lyophilized powder and I need to make it to a working concentration of 25mg/mL

So I know that I need to add $4~mL$ of solution to this powder, which will give me a concentration of the enzyme at $25\frac{mg}{mL}$. What I do not understand is how to decide how much of each of ...
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82 views

Hydrogen peroxide from water

Is it possible that $\ce{2 OH-}$ from water could react to form $\ce{H2O2}$? I mean most autoionization forms $\ce{H3O+}$ and $\ce{OH-}$. However I think it is possible that $\ce{H-}$ and $\ce{OH+}$ ...
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Finding pH of tri-protic acid

I am studying for my final and I am given this problem: A solution of sodium phosphate is made from 10.5 g sodium phosphate in 150 mL of water. What is the pH of this solution Given: Ka1, Ka2. ...
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how protons(H+) react with matter and cause the solution to be acid?

For example if my hands were put in a HCl solution how does the protons in the solution which in high amounts will interfere/react with my hand(skin->proteins..) and cause it to burn...or how protons ...
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Explanation for behavior of acetic acid in aquaponic/hydroponic systems?

Because aquaponics is hydroponics with fish & bacteria, options for adjusting pH are limited. Primarily people use phosphoric acid, hydrochloric acid, and nitric acid (heavily diluted). A less ...
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Adding water on CH₃COONa. What's the new pH?

We have $10 \,\mathrm{L}$ of solution of $\ce{CH_3COONa}$ with concentration $C=1\,\mathrm{M}$ and $\mathrm{pH}=10$. Then we ad $90\,\mathrm{L} \space \ce{H_2O}$. The question is what will be the pH ...
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101 views

What does 0.12N mean on a bottle of sulfuric acid?

I just bought a bottle of sulfuric acid in order to simulate acid rain for an experiment. I was wondering what 0.12N on the bottle means. I need a simplified version of the explanation as I'm ...
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Dissociation of water into H+ and OH-: Does the law of mass action hold at nanoscale?

Suppose water under neutral conditions is confined in a virtual spherical nanocontainer with a radius of 25 nm. To calculate the number of hydronium ions, one uses water dissociation constant which is ...
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What is the pOH of a 0.0100 F solution of dipotassium phtalate?

What is the pOH of a 0.0100 F solution of dipotassium phtalate? pKa1 = 2.950 and pKa2 = 5.408 for phtalic acid. I did it for phthalic acid by calculating pH and then just doing pOH = 14.00 - pH, ...
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47 views

Finding the Ka of a weak acid after addition of a strong base

When 50.00 mL of an unknown 0.2461 M weak acid are titrated with 0.1968 M NaOH, it was found after the addition of exactly 16.00 mL of base that the pH of the solution was 3.79. From this information, ...
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Is there a pH range for “neutral” detergents?

There exist many home made pH scales like these But do any of you know if there is an "official" scale that defines if a neutral detergent is 7 sharp or within a range _______?
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89 views

Net charge of Peptides at pH1 and pH0

Taking Glycine and aspartic acid. As both the amino acids are fully protonated at pH 0 ad pH 1, how does the peptide bond form? Is it a two step mechanism where the OH from an alpha carboxyl group ...
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How can the pH value be unitless? [duplicate]

How can the definition of the pH value $pH=-log(H^+)$ yield a unitless result? Since $H^+$ is a concentration, wouldn't it have units $\frac{mol}{dm^3}$ and therefore following the product rule you ...
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pH Indicators for Hoffman apparatus

I've read that bromothymol blue can be mixed in with the electrolyte in the demonstration of electrolysis using a Hoffman apparatus. The indicator clearly shows the local differences in pH for the ...
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82 views

Ultraviolet acid base indicator

Is there a chemical(s) that provides good discrimination between absorbance curves for different pHs in the UV light spectrum (100-400nm?)
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Titration and calculation of the number of moles after a mix

I have the following problem on an assignment that I don't understand. Given the following balanced equation for the titration of HCl with NaOH: $\ce{HCl + NaOH -> NaCl + H2O}$ The initial ...
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29 views

Is the volume of a protein substrate equal before and after an enzymatic reaction? (pepsin degrading egg white suspension)

I am trying to determine the reaction rate of pepsin at different pH values by performing an experiment. I am using egg-white suspension as the substrate and am adding differently concentrated ...
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Which is the strongest acid?

According to Wikipedia $\ce{HeH+}$ and Fluoroantimonic Acid are the strongest. According to Nature, Carborane acid is the strongest, but Wikipedia says fluoroantimonic acid is stronger... Links: ...
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How could the pH of this solution rise instead of fall when exposed to the atmosphere?

I have a couple of big barrels with a 50L demi-water solution of the following nutrients: $$ \begin{array}{rl} 200~\mathrm{\mu M} & \ce{NH4NO3} & +\\ 30~\mathrm{\mu M} & \ce{KCl} & ...
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42 views

pH of baking soda in water? [closed]

If I dissolve 1g of sodium bicarbonate powder into 400 ml of distilled water, what will the pH of the resulting solution be?
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How to verify the accuracy of a pH meter

One suggestion I received is that I prepare a solution of a known activity and probe the solution with the pH meter. The problem I see with this is that any error in solution preparation can lead us ...
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pH Changes in primary cells

Primary Cells - pH changes during discharge Alkaline Cell: Manganese Dioxide Zinc Alkaline Cell Anode (-) $\ce {Zn(s) + 2OH^{−}(aq) → ZnO(s) + H2O(l) + ...
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What happens when 0.02 mole NaOH is added to a buffer solution?

I am asking this question for my son. (This question is related but we still have our confusions.) We have one liter buffer solution of 4.74 pH which contains 0.1 mole $\ce{CH_3COOH}$ and 0.1 mole ...
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372 views

Adjusting PBS with HCl: pH drift after dilution of phosphate buffer

It is some kind of everyday lab science and with a feel of shame I cannot answer this observation. I noticed a pH drift (~0.5 units) of my 10X phosphate buffer (PBS), when I adjust the pH with ...
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177 views

What is the pH of a solution of HCOONa and HNO3?

Calculate the pH of an aqueous solution obtained by mixing 20 ml of $\ce{HCOONa}$ 0, 1 M and 5 ml of $\ce{HNO_3}$ 0,2 M. ($K_a$ of $\ce{HCOOH}$ $= 10^{–4}$) My try: The number of the moles involved ...
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Is it true that a pH higher than the pKa of an acid make the H automatically disassociate?

Will the hydrogen atom always disassociate if the pH of the solution is higher than the pKa of the acid?
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Using non-food grade NaOH for pH control

I would like to use non-food grade $\ce{NaOH}$ for $\ce{pH}$ water treatment. Any problem with this mixing with water that contains iron? The $\ce{NaOH}$ will be pumped into a well. As a $25\%$ ...
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72 views

Concentration of hypochlorous acid and hypochlorite

Given a total chlorine concentration and the pH and pKa of $\ce{HOCl}$, how would you find the concentration of $\ce{OCl-}$ and $\ce{HOCl}$ disinfectants? If the given total chlorine concentration is ...
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773 views

Calculating pH of diprotic and amphoteric solutions

I am trying to understand this problem and its corresponding solution (complete solution not shown) First off, from the above one can see that the equilibrium constants when $\ce{H2ASO4-}$ ...
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How much can the pH change through dilution?

Consider an acidic solution with Hydrogen ion concentration, $\ce{[H+]}$ of $10^{-5}\:\mathrm{M}$. Since $\:\mathrm{pH} = -\log \ce{[H+]}$ the $\:\mathrm{pH}$ of solution is $5$. Suppose we dilute ...
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Deviation from ideal solutions - activities and concentrations

What are some examples of solutions deviating significantly from ideal behavior, and, by extension, showing pHs significantly different from those predicted by usage of concentrations instead of ...