The branch of chemistry concerned with identifying and quantifying the chemical constituents of matter.

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Solubility of Gold in low concentrations

When preparing ICP-MS calibration standards for trace metal (~100 ppt) analysis, the values for Gold do not remain stable for more than a day. The standards are prepared using commercially available ...
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24 views

Which element should be placed in axial position bulky one or the smaller one?

In one question for finding P(CH3 )2H3 structure ? Which one should be placed in axial position ? I think CH3 should be axial position to minimise repulsion.
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What Affects Tm and Tr In Chromatography?

In chromatography, a mobile phase with analytes is passed over a stationary phase. A given analyte has different solubility in the two phases and consequently spends different periods of time in them. ...
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43 views

Finding structure of C6H12O with several reactions

Full Question : An organic compound A (molecular formula $\ce{C6H12O}$) does not change the colour of acidic dichromate solution. Compound A on treatment with $\ce{H2SO4}$ produces alkene which on ...
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16 views

Quantitative analysis of alcohol

I would like to determine the amount of alcohol present in a given sample of a solution. I would like to do this without spectroscopic methods. This is part of a chemistry project in which I want to ...
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26 views

Experimental melting-point of Arm-and-Hammer sodium bicarbonate is remarkably high(?)

Online literature reports the melting point of $\ce{NaHCO3}$ as ~50 deg. C. Using a standard Mel-Temp II melting-point apparatus and a standard alcohol thermometer, I didn't observe any melting of ...
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24 views

How to weigh an amount of standard by correcting for purity?

I have to weigh-out 6.0 mg of adenosylcobalamin standard that is 93% pure. How do I do this while taking into account a correction for purity?
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22 views

Free Open Source Gas Chromatography Software

Collecting data is one thing, however sometimes one needs to plot or analyse data at a later date when access to the original software may no longer be feasible or possible. Open Source software is ...
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45 views

Is there open source software for SEM EDX data analysis?

This can't be unique to me and would apply to anybody who has to use equipment in other departments has had departments move etc. What open source packages exist to read and potentially manipulate ...
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25 views

What are some good references on conductometry as an analytical technique?

Non of the standard undergraduate textbooks in analytical chemistry (such as Skoog, Harris) discusses conductometry as an analytical technique. I wonder whether this technique is obsolete. Or is it ...
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46 views

What's the future of an organic and/or analytical chemist? [closed]

what can I do with a degree in analytical chemistry other than working in the lab? And what is the future of being an organic chemist? Can I be a researcher in both of them? Or it's better to take ...
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60 views

Can molecular structure be determined without modern characterization methods?

Molecular composition can be determined in some "primitive" ways (1, 2). What about the molecular structure? Is there a way to know what's bonded to what without spectroscopy etc.? By "modern" I mean ...
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62 views

I need to report MoS2 values from Mo and Sulfur numbers

I'm having a hard time figuring out how to do this and yes, I have the molecular weights, just don't know how to calculate. Been 20 years since college. EDIT: I'm working with Copper ores. One ...
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35 views

Identification of solutions by solubility when mixed with each other

$\ce{Pb^{2+} (aq), Cl- (aq), Ag+ (aq), (SO4)^{2-} (aq)}$. You number the four bottles, 1,2,3,4and while numbering them, you notice that bottles 1 and 3 have the word "cation" on their lids while ...
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133 views

Byproducts in Indigo Synthesis?

I have been messing around with making Indigo dye while waiting for bacteria to grow. I have been following the Baeyer-Drewson method. Basically, you mix nitrobenzaldehyde with an acetone water mix ...
3
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1answer
65 views

Reverse Phase Chromatography

Please help me figuring out what is going on with my RP-HPLC protocol. I am purifying a small peptide out of E.coli Culture, heat stable enterotoxin, its amino acid sequence is: ...
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48 views

Calculating Fluoride in toothpaste

I need help calculating the concentration of fluoride in toothpaste. Thanks in advance. A linear regression line was obtained; $$\log(\ce{[NaF]})~(\mathrm{mol~L^{-1}})~ \mathrm{vs~EMF}: y = 59.8x ...
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298 views

Why note the solvent level on chromatography paper when it is removed from the chamber?

Why is it important to mark solvent level on chromatography paper when you remove it from the chamber?
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43 views

Chromatography Separation Quantifying

This is a textbook question: "Suppose you are using chromatography to separate a mixture of two substances. Can you propose a means of quantifying how good or how poor the separation is?" So I got ...
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36 views

How to calculate mass of nanomaterial grown on a substrate

I'm growing graphene on copper substrates and need to know the mass. The graphene is grown via chemical vapor deposition; amounts of reactants are not completely known. The best approach I've thought ...
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63 views

How do I find the empirical formula for Co(C2O4)*H2O with mass of Oxalate and Oxide Product?

I have the formula $\ce{Co(C2O4)*H2O}$ in a reaction that forms cobalt oxide $\ce{Co3O4}$ – My data here says that my oxalate hydrate weighed 0.3283 g and my product oxide weighed 0.1158 g which I ...
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96 views

Near IR spectroscopy vs. IR spectroscopy

I am a backer of this Kickstarter: SCiO Near IR Spectroscopy Here is a link to their technology: SCiO Technology Question: How short of full IR spectroscopy do you think this device is? I have asked ...
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1answer
44 views

to convert ppm gas (N2O) concentrations in microgram nitrogen per gram dry soil basis?

What calculations are needed to convert $\ce{N2O}$ gas concentrations in ppm to micrograms of nitrogen per gram dry soil basis? I measured the concentration of $\ce{N2O}$ in soil samples. I extracted ...
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23 views

Determination of carbon content of steel by liquid chemistry

It seems like the typical laboratory methods for determining the carbon content of steel are to cuppellate it in a stream of oxygen and then measure the volume of the evolved $\ce{CO}$ and $\ce{CO2}$, ...
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28 views

Pb-based pigments and rhodizonate salts

In a previous question, I learned that we can detect lead with sodium / potassium rhodizonate, giving a nice purple color when reacting with pure (elemental?) lead. But in the paint, lead is ...
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113 views

Maximum observed optical rotation through a polarimeter

Is there a maximum optical rotation of plane polarized light that can be observed using a polarimeter? I understand that in a polarimeter, light passes through a filter that converts it into plane ...
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106 views

How to detect lead paint on a bicycle?

Recently I started renovating a bicycle. The frame has been painted probably over 30 years ago, and despite holding well, big patches of rust are showing. So it's time to give the bike a new paint ...
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147 views

What is the purpose of UV-VIS Spectroscopy?

I understand the purpose behind infrared spectroscopy and mass spectroscopy, but UV-VIS doesn't make much sense to me. Through research, I see that it has to do with electron orbitals, and it has a ...
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174 views

Phenyl group in proton NMR

Suppose you have this spectrum and the molecular formula of $\ce{C10H12O}$ The structure is My problem is with the peak at ~7 which is an H-Benzene signal, with quartet splitting and a relative ...
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181 views

How to analyze a acid and salt mixture using titrimetry?

Given a mixture of $\ce{HCl}$ and $\ce{MCl3}$ and the following dissociation constants for $\ce{M(OH)3}$, how can the concentrations of $\ce{HCl}$ and $\ce{MCl3}$ be determined separately by titrating ...
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28 views

solution concentrations [closed]

I think I'm making this more complicated than it needs to be, but here it is: I have 7 drug solutions, all 1 mg/mL which need to have the following concentration in urine: A: 25,000 ng/ml B: 25,000 ...
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1answer
61 views

Role of Acetonitrile and Ammonium Acetate buffer in Leucomalachite Green stock solution?

I am trying to repeat an experiment conducted by FDA on Malachite Green (MG). According to this paper, ...
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37 views

How are hormone levels measured?

I have been searching google and didn't found any links that describes how this process is performed - I mean the chemical procedure, not the process of taking the blood from the vein.
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Fertiliser analysis - Why doesn't it show ureic nitrogen when it does have urea?

I have had two types of urea fertiliser analysed, the results are as follows: $\ce{46\%N}$ (46% nitrogen) - which is sold as a urea fertiliser, tests at 46.1% ureic nitrogen. $\ce{38\%N 19\%S}$ (38% ...
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Choosing the instrumental techniques for chemical analysis [closed]

Since every technique has its goods and its bads characteristics, it's a bit hard for me to choose between them to determine specific elements, methods such as UV-VIS spectroscopy, IR spectroscopy, ...
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Qualitative spectrographic analysis

In order to identify the presence of a specific element, one must identify at least three ultimate lines of that element in the specter. Those lines are the ones with the highest intensity. I ...
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Know any micropipettor that is acid resistant?

We pipet concentrated nitric and hydrochloric acids. our current pipettor is rainin lite but its piston is metal and thus corrode easily. We discussed this with our inhouse technician and he ...
2
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1answer
39 views

What is the mechanism for electrospray ionization?

I've been asked to Descibe the ionization mechanism used in electrospray ionization I know that this is a desorption ionization source, which uses a high electrical field as the ionizing ...
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89 views

Estimate the concentration of HCl and volume of 6 M HCl required to complete precipitate each of the given salts

In our chemistry lab we performed the following experiment below. Given that $K_\mathrm{sp}(\ce{AgCl}) = 8.2 \times 10^{-11}$ and $K_{\mathrm{sp}}(\ce{PbCl_{2}}) = 1.7 \times 10^{-5}$ ...
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141 views

What are some books, websites, etc. where I can find the detailed protocol for standardization of sodium thiosulfate with dichromate?

I am looking for a book or website such as "Vogel's Textbook of Quantitative Chemical Analysis" where I can find methods for analyzing/standardizing a particular species easily. I am not looking for ...
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2answers
52 views

2,4-dinitrophenyl hydrazine test

I found this reaction over here: which illustrates the carbonyl test but looks fuzzy. Assuming that the R in the product is a typo for H, I couldn't conserve the number of Nitrogen atoms. ...
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1answer
46 views

Is the following reaction redox? [closed]

Is the test of sulphur using sodium nitroprusside a redox reaction?
3
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34 views

Stability constant of complexes

I know that this constant tells us the strength of the interaction between the metal and the ligand, so should it also mean that the higher the constant, the stable the complex ? I need to make sure ...
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52 views

Different elution profiles of carvacrol and thymol

I have identified carvacrol and thymol via thin-layer-chromatography and via gas chromatography On a normal silica plate the thymol has a higher Rf-value then carvacrol. The explanation for this would ...
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60 views

Photometric titration

If we have $\ce{A + T -> P}$ where $\ce{A}$ is the analyte, $\ce{T}$ is the titrant, and $\ce{P}$ is the product, photometric titration happens only in one condition, that one of the following ...
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11 views

Optional determination techniques in AAS

I have tried to find information about this case but I couldn't find anything specific. The key point of instrumental methods of analysis, is for the student to be able to know which one of the ...
6
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1answer
75 views

Determination of mercury in AAS

Its known that the only method to determine mercury in atomic absorbtion spectroscopy is the cold vapor method. What is the reason that mercury can't be determined with other methods, such as flame, ...
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23 views

How to confirm the type of bonding taking place between two substances?

For example ink on paper: how can I confirm that the bonding is van der Waals and not covalent? Similarly, the same question can be asked about other interaction such as hydrogen bonding, ionic ...
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652 views

Converting g/L to mol/L

I know I should divide $\mathrm{g~L^{-1}}$ by the molar mass of the substance, but I don't seem to find the specific answer on Google. So just to be sure: If I have ...
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Atomizers in AAS

Electeothermal atomizer ( graphite furnance ) and flame atomizer, are the instruments which help us to convert the analyte into the gas state and they both achieve that. My question is, what's the ...