Questions tagged [elemental-analysis]
The science of determining the elements a compound is made of or deriving the sum formula thereof. Can be applied both to practical and theoretical questions
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What causes HPLC peaks to look like gauss curves?
I was wondering how the form and curvature of HPLC peaks come to be. As I understand it, the mobile phase which contains the analyte, runs through the column. Many times, the distribution equilibrium ...
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Why aren't lasers used as light sources for atomic absorption spectroscopy?
Atomic absorption spectroscopy yields extremely narrow signals. It is difficult to separate white light with sufficient precision using monochromators, and hollow cathode lamps are often used as light ...
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Lassaigne's test for sulfur
The sodium fusion extract is acidified with acetic acid and lead acetate is added to it. A black precipitate of lead sulphide indicates the presence of sulphur.
What is the need for acidification of ...
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Negative absorption coefficient
What does a negative absorption coefficient mean?
In detail - I participated in a Synchrotron virtual laboratory. I have to analyze the results and understand what a negative absorption coefficient ...
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Prepration of standards for analysis of chromium using AAS
I have conducted experiments to study specific adsorption of chromium in various soils and I made my all solutions of cr with using 0.01M NaNO3 as background electrolyte. (I made solutions of 5 ...
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Preparation of isotopic CO2 standards from Sn-encapsulated CaCO3
I wish to prepare isotopic CO2 gas standards for highly 13C enriched CO2. The CO2 concentrations will be ~1000 ppm, with the balance either N2 or zero air.
My plan is as follows:
Encapsulate labeled ...
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Which salts give the sodium carbonate bead test?
Apart from the borax and the phosphate bead tests, there's also this one.
It's done by heating the white bead of sodium carbonate and the salt with potassium nitrate; green and yellow colours ...
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Quantitative elemental analysis in mixtures with internal standard normalization
I am trying to make a quantitative model for Laser Induced Breakdown Spectroscopy (LIBS) analyzing metal alloy samples. I am using an internal standard normalization (so far it produced the best ...
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Free refined value in Rietveld
I have a question about Rietveld refinement
The author of this paper claimed that the free refined CN ligand is 1.081.
However, they does not show how they got that number. They stated it was based ...
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What is the correct way to specify the weight fraction from bulk compositional data with a listed total % (e.g. from XRF, ICP)?
TL;DR = With bulk composition results, such as from X-Ray Fluorescence (XRF) testing, is the mass fraction of a given analyte that analyte given as a % or the analyte divided by the given total mass %?...
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Chemical Composition of NMC cathode in lithium ion battery
I am working with lithium ion batteries having the cathode material as NMC i.e. LiNixMnyCozO2, wherein x + y + z = 1. The proportion of Nickel, Manganese and Cobalt in the cathode varies, but mostly ...
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What happens to chromium (as Cr2O7-) in the plasma of the ICP?
I have recently been analyzing some biological samples for chromium using a standard Cr(VI) solution for external calibration.
Cr standards are typically supplied in a 2% nitric acid matrix. That ...
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Determining the chemical formula of a polyiodide Salt
I've got a compound with formula $\ce{N(CH3)4.I(I2)_x}$. By mass I've got $\pu{0.138 g}$ of $\ce{I2}$ present out of $\pu{0.189 g}$ of polyiodide added. How do I find $x$?
This is the exact part of ...
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How do I calculate the molecular mass of a complex in a complexometric titration with EDTA?
I had to titrate 0.35 mmol (3.2 g) of $\ce{Co2F2(Hdmpz)6(BF4)2}$ in a solution with 10 drops of 37 % $\ce{HCl}$, 10 mL of 4 M $\ce{NaOAc}$, 25 mL water and xylenol orange as indicator with a 0.05 M ...
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Cobalt Nitrate Test
As,
$$\ce{ZnCl2 + Na2CO3 -> ZnCO3 + 2 NaCl}$$
$$\ce{ZnCO3 -> ZnO + CO2}$$
$$\ce{Co(NO3)2 -> CoO + 2NO2 +\frac{1}{2}O2}$$
Hence, $\ce{CoO + ZnO -> CoZnO2}$
here, $\ce{Zn_{1-x}Co_xO2}$ (...
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