Analytical Chemistry Forum | Forum profile

Quote from: machozitatu on Today at 09:15:44 AM I calculated it out and got 3.5 for X. so that means that 3.5ml of the solute is extracted initially or is that 3.5 mmol extracted. so for the next extraction I would start with 26.5ml and do the same thing (since 30-3.5 is 26.5). If the answer you got was 3.5, then that would be 3.5 mmol extracted, and so 26.5 mmol left in the organic to plug into a second iteration of the equation. Note that I...

calculate the pH of the solution prepared by adding .10mol each of hydroxylamine and hydrochloric acid in 500ml of water. I was trying to set this up and my understanding is that these two compounds are in water and are "reacting" together to form hydroxylamine hydrochloric acid. with that said the OH in the product would be the determining factor for pH. so would I use the Ka of hydrochloric acid to find OH and then find pH...

I can't see where dilution factor comes into play. If you know volume and concentration of EDTA you can calculate number of moles of calcium in the sample - and knowing your sample was 10 mL you can easily calculate mass of calcium per 100 mL. Volume of the sample after NaOH and water were added is irrelevant.

Depending on Levels, AAS, ICP-AES and ICP-MS, seem to be the accepted techniques at the moment.

I did think, at one point, that there was some kind of organic 'iron absorber' within the matrix.  But then I said it was improbable that some organic species of significant concentrations would ionize itself and respond to exactly the same potential as Fe(III).  It's not something I would rule out... but because this signal is the representation of an oxidized species, it's hard to imagine...

Quote from: IndieSci on Yesterday at 03:49:57 PM Lead chloride is slightly soluble, and I think he is probably working on very dilute solutions so this probably wont work. Yeah, that's what I'm not understanding. If it is high concentration of lead the precipitate will be obvious...if not, it won't be near as obvious or able to be seen at all. 

Ok well I can describe my attempts for #10, I don't know much about 11... I would scan what I did, but I'll try and describe the gist of it. For #10, I plotted absorbance with the fraction. It pretty much looked like a plot of 2 points with the given values. I can't think of what else to do after that...I tried using Nerst equation/stuff outlined in the original question to solve for the fraction, but I'm...

thanks jgk much obliged

Hi i work on titration of pb using Xylenol Orange tetrasodium salt indicator for metal titration. if any one he have idea about other indicator may i can use it instead . because its difficult for me to find this one. thank you in advance for further information will be ready. Ash

Lead chloride is slightly soluble, and I think he is probably working on very dilute solutions so this probably wont work.