A measure of the acidity or basicity of an aqueous solution.

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1k views

What is the unit of pH?

I'm making some graphs and I have to label the axes. I want to be extra careful and put the units in even though the meaning of pH is well known. But I have a problem (though a simple one)- pH is a ...
0
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1answer
52 views

Preparation of a benzoate buffer [on hold]

What mass of sodium benzoate should be added to 140.0mL of a 0.17M benzoic acid solution in order to obtain a buffer with a pH of 4.25? To find mass you need mols i believe and to find mols you need ...
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3answers
29 views

pH and materials selction

I working on the Navy study guide for their nuclear engineering programs and I am not a Chemist. Thus, I have come here to try and develop a better understanding of the subject matter. I am trying ...
1
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2answers
70 views

Given the volumes: determine the pH and the final temperature of a mixture knowing only the initial pH and the temperature of the un-mixed components

I have a pretty basic question but the last time I took Chemistry was in 2007. I am studying the Navy's Nuclear study guide for their interviews and one of the question I am faced with is below. ...
2
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0answers
59 views

What is the pKa of the oxonium / hydronium / H3O+ ion?

Although the wikipedia page on Hydronium indicates a pKa of -1.74, I noticed in the discussion of this page that the subject seems debated (cf. http://en.wikipedia.org/wiki/Talk:Hydronium#pKa.3F) ...
1
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1answer
38 views

Cant extract a pyridine tetrazole

So I have synthesised a compound which is basically a pyridine ring conected to a tetrazole. The procedure suggested to precipitate it at pH 1 but it didnt... It then suggested to extract it with ...
2
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1answer
31 views

Volume required to dilute solution for a pH change

A 100 ml solution of NaOH has a pH of 13. What volume of water, in mL must be added to change the pH to 11? My Steps: So, begin by calculating conc. of [OH-] for pH 13. Then find the moles by ...
3
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1answer
31 views

Red Cabbage Indicator colour change with Sodium Metabisulphite

I made some pH indicator by boiling and straining cabbage juice and in an effort to keep it from spoiling for a while without having to store it at fridge temperatures I added some wine making ...
7
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2answers
187 views

Approximate time for pure water pH to equilibrate in open air?

I'm a complete non-chemist, so I don't know how to calculate this, or even what to google for (my searches yielded esoteric research papers). I'm doing some hobby experiments, and I'd like to know ...
-1
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1answer
47 views

Henderson-Hasselbalch pH question help [closed]

I need help on this: Determine the volumes of .1M $\ce{CH3COOH}$ and .1M $\ce{CH3COONa}$ required to prepare 10.0 mL buffer of each of the following pH values: 3.7 4.7 5.7
2
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1answer
62 views

What is the reason a grain of salt alters the perceived bitterness of coffee by such a high degree?

Coffee served hot can be quite bitter (presumably high pH). Several people I have known will add a single grain of salt to the coffee - which reduces the perceived bitterness. My question is: What ...
1
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1answer
74 views

Calculating approximate pH of polyprotic acids

When I took up ionic equilibria and titrations after a long break, I found it hard to solve the questions regarding pH calculations of polyprotic acds. Consider these two questions as examples:- ...
5
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3answers
736 views

the reason behind the steep rise in pH in the acid base titration curve

Most books refer to a steep rise in pH when a titration reaches the equivalence point. However, I do not understand why... I mean I am adding the same drops of acid to the alkali but just as I near ...
1
vote
1answer
250 views

Shouldn't the pH at the equivalence point always be 7?

I learned in class that the equivalence point in an acid-base titration is reached when the solution contains equal number of moles of $\ce{OH-}$ and $\ce{H+}$ ions. However, in a weak acid and strong ...
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2answers
515 views

What is the pKa Range for weak acids and bases?

Am I correct in assuming that the following is true? $pK_a < 3$ is for a strong acid $3 < pK_a < 7$ is for a weak acid $7 < pK_a < 11$ is for a weak base $pK_a > 11$ is for a ...
0
votes
3answers
165 views

What is the pH of 1M Glycerol?

If the pKa of Glycerol is 14.15. How do you calculate the pH for it? I assume that the Henderson-Hasselbalch derivative that works for weak acids and bases is not applicable here.
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0answers
99 views

Difference in pka between PEG and Ethylene glycol?

What is the difference between the pKa for Polyethylene glycol (PEG) and Ethylene glycol (EG)? Is there a difference? There are also different types of PEG, monomethyl ethers and dimethyl ethers, do ...
0
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0answers
95 views

Calculating the pH of a buffer made from KHP (potassium hydrogen phthalate)

I have a question regarding the pH of a buffer, and how to calculate it. The buffer was prepared by: 1) Mixing 25 cc of 0.1M NaOH solution to 25cc of 0.1M KHP solution (i.e. potassium hydrogen ...
0
votes
1answer
64 views

What is the pKa of 2-methyl-2,4-pentanediol?

What is the pKa of 2-methyl-2,4-pentanediol? Is there a reference that contains a list of pKa values for various molecules that I can consult or is there a way to determine/estimate the pKa of this ...
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0answers
79 views

Does the number of H+ ions in solution go up on dilution of a weak acid?

In my textbook, a footnote says: In case of weak acids, on dilution the total number of $H^{+}$ ions in solution increases because dissociation of the weak acid increases This didn't make sense ...
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0answers
52 views

Why is Buffer capacity maximum when the ratio of its components is 1?

A buffer consists of a weak acid and its salt or weak base and its salt. When the ratio of weak acid and its salt in a buffer (or the ration of weak base and its salt) is equal to 1, we say that the ...
0
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2answers
75 views

What is the importance of using a pka value instead of a pkb value when describing drug chemistry?

Why do we only consider the $pK_a$ value of a drug regardless of whether it is an acid or base? Why do we not use the $pK_b$ value?
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1answer
60 views

What is the correct form for the acid-base equilibrium constant potential: pK_a or pK_A?

In science, the acid-base equilibrium constant potential is denoted or depending of the source (lowercase or uppercase A). Since it is the potential of the acide-base equilibrium constant defined as ...
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0answers
24 views

What are the products formed by a typical wood fire? [duplicate]

What are the products formed by a typical wood fire? I tested the ash from my fireplace and found it to be on the acid side. While this question has been partially answered in answers to another ...
0
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1answer
109 views

why should colorimetric titration of weak acid and weak base should not be done in laboratory?

why should colorimetric titration of weak acid and weak base should not be done in laboratory? Also how to draw the curve of weak base or Weak acid added and ph..??
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0answers
23 views

Isoelectric point pH, mV, for a metal oxide nanopowder

I'm trying to make a solution of TiO2 that will coat stuff in as dense a monolayer as possible. To do so, I'm using nano sized TiO2 particles and trying to get them to get as close to each other as ...
0
votes
1answer
154 views

Why does this shortcut work for calculating pH (proof required)?

My teacher gave me a shortcut regarding calculation of resultant pH if the solutions are mixed and if the difference between the pH of individual solutions is 1. If there are two solutions, the pH ...
0
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1answer
53 views

What are the properties of various solutions at pH <2 that may cause injuries?

For example, why do some solutions not cause any injuries at pH 2 while HCl does?
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3answers
511 views

pH range outside convetional 0-14 [duplicate]

So, I lately asked this question: Is a pH value outside 0 - 14 possible? My teacher responded with: yes, it is, but very difficult to achieve. Then on the internet, I found multiple answers, one ...
2
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1answer
34 views

Isoelectric pH of colloids?

How did we derive the relation between the isoelectric pH and the dissociation constants for the amino and carboxyl groups on zwitterionic amino acids. $$pI=\frac {pK_{a1}+pK_{a2}}{2}$$ where ...
0
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2answers
249 views

Teeth friendly alcohol drinks

What is the best alcohol for your teeth according to the pH? Is it true that if the acidity of the drink is higher (and ph is lower) than it's worse for your teeth (enamel erosion + bacteria friendly ...
8
votes
2answers
324 views

Why does water dissociate to H3O+ and OH- rather than H+ and OH-?

Why does water dissociate to $\ce{H_{3}O^{+} + OH^{-}}$ instead of $\ce{H^{+} + OH^{-}}$? This question came to surface when I was learning about acids and bases, and learned this definition: ...
0
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1answer
181 views

How to estimate pH?

How you you calculate/estimate the pH of a solution with 3 components all of different pHs? Is there a paper describing this? For example: 0.1M Buffer PCTP at pH 9.5 1.6M Sodium Dihydrogen Phosphate ...
0
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1answer
480 views

Calculating the pH of a solution of Ca(OH)2

A solution prepared by dissolving $2.8 g$ of lime, $\ce{CaO}$ in enough water to make $1.00 l$ of lime water ($\ce{Ca(OH)_{2(aq)}}$). If solubility of $\ce{Ca(OH)2}$ in water is $1.48 g$. The $p\ce H$ ...
2
votes
2answers
254 views

Does the hydrolysis speed increase when more H+ ions are in the solution?

Does the hydrolysis speed increase when more $\ce{H+}$ ions are in the solution? So if I were to use $\ce{H2SO4}$ instead of $\ce{HCl}$ (same volumes) then $\ce{H2SO4}$ will be the most effective?
2
votes
1answer
138 views

Normality of an H2SO4 solution

If pH of the solution is zero, what would be the normality of $250 \, \text{ml}$ $\ce{H2SO4}$ solution? My work: $\text{pH} = 0$, hence the concentration of $\ce{H+}$ ions is $1 \, ...
16
votes
6answers
2k views

Is a negative pH level physically possible?

A friend of mine was looking over the definition of pH, and wondering if it is possible to have a negative pH level. From the equation below, it certainly seems possible--just have a $1.1$ (or ...
3
votes
1answer
32 views

Less maintenance-dependent continuous pH testing

I am creating an automated chemical component mixing system (DIY project). One of the features required is continuous monitoring of pH value in my main solution. I do not need it to be very precise, ...
4
votes
2answers
463 views

How do indicators work when they mixed with each other?

Methyl orange, bromothymol blue and phenolphthalein indicators were mixed together to form a solution. Over what pH range would the solution be yellow? I cannot understand the question. If two ...
2
votes
1answer
390 views

Effect of dillution on titration

When we are titrating acid/base using ph meter we add distilled water to immerse the ph electrode. Won't this affect the concentration of the acid/base: I mean isn't this dillution. Won't this ...
1
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2answers
274 views

How can I measure the pH of high-viscosity fluids like dough?

I would like to measure the pH value of dough with a pH-Meter, to ensure a pH value of 4.1 (max). Because of the high viscosity I would thin down the dough with demineralized water for two reasons: ...
1
vote
1answer
2k views

The influence of lemon juice & sugar on the ph-value

If I add equal amounts of lemon juice and sugar into water, does the ph-value remain unchanged, as both cancel each other out? This question arose in my head as I learned that pouring milk into ...
4
votes
1answer
2k views

What chemicals are in tap water that gives it a slightly basic pH level

In chemistry, we recently did a lab where we observed the different ways of reading pH of several different substances. We used things such as red cabbage juice, litmus paper, pH paper and a pH probe. ...
3
votes
3answers
296 views

On the scale of stuff with a pH

I am a confused (and somewhat anal retentive) non-chemist who is trying to understand what pH is. I have come to understand it is a measure of acidity, but I have not yet figured out what that means ...
2
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2answers
199 views

A question about pH

Why don't we need to consider about the $H^+$ ions of water when finding the pH of 0.01M of HCl solution? The pH value of something is depends on the molarity of $H^+$ ions. But the teachers say ...
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1answer
584 views

Chemical reasons for choosing Salt Water or Chlorinated pool?

I am currently researching as too which is better for maintaining the chemical balance in a swimming pool. I have obviously tried the standard Google search for ...
2
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1answer
342 views

Buffers and pH question for exam review

A buffer is made from 50mL of 1.0M benzoic acid (Ka = 6.3E-5) and 50mL of 1.0M sodium benzoate. a) Calculate the pH of this buffer For this do I simply use -log(6.3E-5)? b)Calculate the new pH when ...
-1
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1answer
115 views

Acids / Bases - Need some clarity for final exam [closed]

I'm studying for my final exam, and these are the questions I got wrong on the mid term, could anyone help correct me? I know people are against giving answers for homework, so I must add that is now ...
0
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1answer
3k views

How do you find the pH of a solution with a known pKa and Molarity?

How do you find the pH of a solution with a known pKa and Molarity?
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0answers
164 views

Calculation of partial charges and protonation/deprotonation states depending on pH

What is the best method for calculating partial charges and protonation/deprotonation states of a small molecule such as phenol or caffeine, depending on the pH? For instance, it is well known that ...