Ph Definition and 512 Threads

For a lab I need to create a 0.1M solution of NaOAc buffer at pH 5 It's been a while since I worked with buffers. I'm struggling to find a way to get both the proper morality and proper pH. My first though was to create a 0.2M solution of acetic acid and titrate it to pH 5 using sodium...

The recipe for luminol solution that I found on the internet is: 0.2g luminol, 4.0g Na2CO3, 24.0g NaHCO3, 0.5g (NH4)2CO3, 0.4g CuSO4 dissolved in 1 dm3 of water. How can I alter the pH of the solution to get a range of pH values from 7 to 14 without affecting the chemisty of the solution?

Homework Statement I have some data from measuring EC in solutions and I don't know how to convert EC to pH Homework EquationsThe Attempt at a Solution I use Arduino for programing. Values of ADC of EC that I collect from microcontroller are 80 ( for EC : 0.2mS/cm ) , 90 ( for EC ...

Hello everyone, In a few weeks I am going to have my anorganic chemistry laboratory experiments, and I want to buy one PH-Meter. I'm looking for a model that is realible but not expensive (in the order of 20-40 bucks) I'll be happy to hear your suggestions Thanks :smile:

I would like to ask for somebody to point me in the right direction - any literature I could read - regarding the mechanism behind color changes that an organic solution undergoes due to changes in pH. I am not referring to organic indicators or dyes, specifically. I have observed in my...

Homework Statement If the text is too small, it reads: 'A student measured the pH of water at various temperatures using a pH meter and obtained the following results: (table showing pH decreasing as temperature increases) The student was unsure whether the results were accurate or if the pH...

I am amused by how skillfully most of the texts I have avoid discussing reference electrodes in electro-chemical measurement-They simply start out by discussing the H2 and Calomel electrodes with no further explanation. Both have certain hazards and seem overly complicated. So--why are these...

Which property of compounds, organic ones in particular, can help us predict their charge(s) at a specific pH? Is pKa/pKb the only one? I would like some confirmation on this. Thank you very much!

Hi! I don't know much about chemistry but was hoping that some of you guys could help me with a quick question. I build wooden model ships of sail as a hobby. One "trick" for giving sails and rope an aged look is to dip them in coffee or tea and let the tannin dye the materials. The problem...

Knowing Ks=6⋅10−38 for Fe(OH)3 in neutral solutions, calculate the minimum pH of an acidic solution in order to completely dissolve 10 mg of Fe(OH)3. Data: Volume = 0.1 L. I set out the equation for the equilibrium constant. having first calculated the concentration or iron ions (9.35899*10-4...

Homework Statement A 50.0 mL aqueous solution of sodium hydroxide has a pH of 12.50. If 36.00 ml of 0.0200 mol/L sulfuric acid is added to this sodium hydroxide solution, what will be the new pH of the resulting solution? Assume that the temperature stays constant at 25C, and that the volumes...

Hi, I've calibrated our pH meter using 4.01 and 7.01 buffer solution, but I'm not sure if the probe has dried out at some point. So I want to check the calibration, I have some HCl > 37% that I can use. Just a quick question, since pH is on a log scale so I have to make solutions every ten...

Do pH and pKa refer to the same concept? The same question for pOH and pKb also. What does kWh actually mean. In have read that it is the ionic product and is the product of [H+] and [OH-] but what does it indicate. Does it have any full form?

Homework Statement So we did a lab in organic chemistry where we did a resolution experiment for enantiomers and in the separatory funnel we had sodium tartrate/tartaric acid left in the aqueous phase of the funnel. It asks why this compound is more soluble in high ph solutions as compared to...

Homework Statement 1) Which solution has the higher pH, a 0.001 M solution of NaOH or a 0.001 M solution of Ba(OH)2? 2) Would a 1.0 × 10-8M solution of HCl have pH < 7, pH = 7, or pH > 7? My professor said she shouldn't have put HCl as the solution, but that it doesn't matter apparently...

The have to prepare the buffer but I really don't know how. Is the any formula for the buffer preparation? Ps. Sorry but one more thing, what does the "/" between Na2HPO4 and H3PO4 mean?

Homework Statement Phosphate, present to an extent of 0.01 M, is one of the main buffers in blood plasma, whose pH is 7.45. Would phosphate be as useful if the plasma pH were 8.5? Homework Equations pH = pKa+log[A/HA] Ka1 = 7.11x10^-3 pka1= 2.148 Ka2=6.34x10^-8 pka2= 7.198 Ka3 = 4.22x10^-13...

Its a very simple question . So when the carboxylic acid radical -COOH is standalone in an aliphatic molecule without any other acid or basic radicals Pka would be around 4.5 . But when something like -NH3+ is present in the same molecule the Pka for -COOH changes , even though -NH3+ wouldn't...

Hello, I need to make a 0.2 M Tris-Acetate Buffer pH 6 and I can't find a protocol for this specific buffer. I know that I can make a Tris solution (i.e. 12.11 g of tris(hydroxymethyl)aminomethane in water), adjust the pH to 8 and dilute to 1000 mL with water. Is the same true for pH 6...

I am "proofing" various pH probes in an in-situ fresh water environment--this is a low electrolyte environment where such probes typically do not perform very well. I want to routinely sample the water and obtain accurate pH data for comparison. Can someone enlighten me on the what modern (non...

Homework Statement pH fluctuations need to be determined at a maximum dosage of 50mg/L of 93% sulphuric acid . Homework Equations If the start pH of the water sample is 8, how much will pH be lowered by adding of 50mg/L of 93% sulphuric acid, and what is the correlation between the different...

What is the pH of a solution made from 34.6 ml if 3.45*10^-4 M of H2SO4 added to 41.7 ml of 4.56*10^-4 M of Al(OH)3? I know how to find H+ and OH- and pH I also know how to use x mol / L, but I cannot get them to click together. Everyone keeps telling me to use RICE but my professor never...

Homework Statement Equal volumes of two solutions of hydrochloric acid are mixed. One solution has a pH 1 while the other pH 5. The pH of the solution obtained is? A) Less than 1 B) Between 1 and 2 C) 3 D) Between 4 and 5 E) More than 5 Homework Equations -log[H+] = pH 10-pH = [H+] The...

Hello! I am trying to crack the following problem: What is the pH of a solution formed by mixing 125.0 mL of 0.0250 M HCl with 75.0 mL of 0.0500 M NaOH? Here is how I am approaching the issue: both HCl and NaOH are strong acid and base respectively. Hence the concentration of [H3O+] =...

What are some good methods to determine properties such as light quality/intensity, pH, and water solubility of quantum dots? Other properties are welcome, as well. I do not have a college lab available, so some equipment may not be possible to get. This is for my science fair project next year...

Homework Statement [/B] I work in a lab, normally we evaporate our acid and dilute with water, but I have 300 samples and this would destroy the fume hood so I need to raise the pH using ammonia. known data: Samples are 40ml of 9M HCl I need to add Xml of XM ammonium hydroxide (aka aqueous...

Homework Statement Calculate the the molar concentration of H3O+ ions and the pH of the following solutions: a) 25.0 cm3 of 0.144 M HCl(aq) was added to 25.0 cm3 of 0.125 M NaOH(aq) b) 25.0 cm3 of 0.15 M HCl(aq) was added to 35.0 cm3 of 0.15 M KOH(aq) c) 21.2 cm3 of 0.22 M HNO3(aq) was added to...

Homework Statement pKw for water at 10 deg Celsius is 14.54. What is the pH of pure water at this temperature? Homework Equations kHw = [H+][OH-] The Attempt at a Solution I don't even know where to start on this one

Homework Statement [/B] Just a general question to see if I'm doing this right. The volume just doesn't seem right. Anyways we have a water supply of 1.6 million gallons with a pH of 9.93. We want to get the water to a pH of 6 using a 30% HCl solution.Homework Equations M1V1+M2V2=M3V3...

Homework Statement Hi everyone. 1) If I perform a titration with a buret not rinsed in the titrant, then how will the pH of the endpoint be affected? 2) Also, if the volumetric pipet used to measure the analyte is not rinsed with the analyte, how will that affect the pH of the endpoint...

Homework Statement Homework Equations N/A The Attempt at a Solution I am trying to understand the above ph diagram (for a vapour compression cycle), In some examples, point 1 is situated as above in the image (i.e. to the right of the saturated vapour line) and at other times it's situated...

Homework Statement 2. Homework Equations q = w+Δh The Attempt at a Solution I fail to understand how they obtained the 3 equations at the bottom. For the first one I understand that q = Δh since w = 0 but why is it h1-h4 rather than the other way around? Also, why does this h1-h4 equal...

Homework Statement 6.84 gram aluminium sulfate (Al2(SO4)3) is added into water so the volume of the solution becomes 2 liters. If we know that the atomic mass Al = 27, S = 32, and O = 16, determine the pH of the solution! (Kb Al(OH)3 = 5*10^-9) Homework Equations ##[H+] =...

Hello everyone, First of all thank you for your help. I'd like to know if there are any ph testers for solids not diluted and where can I buy them and how much would they cost. Thanks!

Homework Statement 30 mL CH3COOH 0.2 M is mixed with 60 ml CH3COONa 0.1 M and then added with 10 mL HCl 0.1 M, then what is the pH of the solution ? (Ka = 10-5) A. 3 B. 5 - log 1.4 C. 5 - log 2 D. 4 - log 1.4 E. 5 + log 2 Homework Equations [H+] = Ka * [HX] / [X- ] ---- buffer [H+] =...

I bought a PH meter with glass electrode. I calibrated it using a buffer solution following the instructions. When I measure the PH of tap water, vinegar, or other simple liquids it initially keeps changing but eventually it stabilizes at the correct value. But I tried to measure gastric juice...

Homework Statement Methyl red has the following structure [not listed here on this post] Ka = 5.0 * 10 E -5 It undergoes a color change from red to yellow as a solution gets more basic. Calculate an approximate pH range for which the methyl red is useful. What is the color change and the...

Homework Statement Zinc hydroxide has the chemical formula of Zn(OH)2. It has a very low solubility. What is the solubility in g/L of Zinc Hydroxide in a solution with a pH of 8? Homework Equations zinc hydroxide formula 14-pH = pOH[/B]The Attempt at a Solution 10^-6 (the pOH) gives me the...

Homework Statement What was the concentration of acid S before the titration? Homework Equations MaVa=MbVb The Attempt at a Solution So for this problem, the solution manual suggests that we use the formula above to solve for the pH of acid S before the titration. But why do we use the...

Dear PF Forum, I would like to thank this forum for providing me invaluable helps lately. I'd like to understand ORP in water. I'm aware that PF discourages member for not doing research first. I've (been) reading redox, antioxidant, pH, covalent, including...

Dear PF Forum, Actually I want to study how antioxidant can benefit for our health. But, my understanding in chemistry is very limited. Perhaps I have to go back and study pH, first. I have read many sources in the internet. And this is one of them...

I understand that alanine salt ooks like this: However, does it look like that in solution? Does the salt dissociate? I know that alanine salt has a pH of about 6.113 because it is the average of the 2 pKas. However, if this salt dissociates, it seems that the carboxyl group is a weak base...

Hi, I'm stuck on part b) of the question below: Q: In order to perform pH determinations with a glass electrode, the cell potential was measured for threestandard solutions with the following pH values at 25 C: 2.04, 7.05, and 9.20. The cell voltage readout(in mV) for each of the above solutions...

Hi, I need to conduct experiments at fixed pH. The complication is that the solution I'm using will have NaCl in it. So if I add HCl or NaOH to make the solution more acidic or basic, the conductivity of the solution (as measured by a conductivity meter) will change due to the added Na+ or Cl-...

Homework Statement 500 mL KOH solution (0.1 M) is mixed with 500 mL HNO2 (0.1 M) so that the reaction becomes: ##KOH + HNO_2 \rightarrow KNO_2+H_2O## If Ka of HNO2 is ##5 \times 10^{-4}##, determine the pH of the solution 2. The attempt at a solution ##KOH + HNO_2 \rightarrow KNO_2+H_2O##...

We are currently trying to measure pH levels on the (wet) surface of metals as part of a study about corrosion. The surface may have a non-conductive protective layer. - is it feasible to measure pH on a planar surface (dry or wet)? Which kind of sensor probe can be used for this task? -...

Homework Statement Determine the pH of the solution (to 2 decimal points) after the addition of 50.0 mL of 2.5 M nitric acid (HNO3) to 500 mL of 0.500 M BIS−TRIS propane (C11H26N2O6), a weak base). Assume that the 5% approximation is valid and that the volumes are additive. The pKa of BIS−TRIS...

Homework Statement It's all in the title. Correct answer: pH = 7,20. K_a (HNO_2) = 4,0 \cdot 10^{-4} Homework Equations K_b = \dfrac{K_w}{K_a} K_b = \dfrac{HB^+ \cdot OH^-}{B} The Attempt at a Solution NaNO2 fully dissolves in water giving 6,0 \cdot 10^{-4} M \, NO2^-. Now water forms an...

Homework Statement hi so in my lab class we made a buffer solution by mixing 20.00 ml of 0.100 M Sodium Hydroxide and 40.00 ml of 0.100 M of acetic acid. We then poured 15ml of this buffer solution into a beaker. So we essentially have 15 ml of this buffer solution in the beaker. We then added...

Homework Statement [/B] NH3(aq) is a weak base with Kb = 1.8*10-5, Calculate [OH-] in a solution that is made by mixing togeather 500ml of 0.20M NH3(aq) and 500ml of 0.20M NH4CL(aq), what is the value of Ph?Homework Equations Henderson Hasselbalch: ph = Pka + log([conj.base/acid]) As well as...