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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Why is there a [M-1]+ in lieu of a parent signal in the Mass Spectrometry of Primary Alcohol Chains?
I have looked virtually everywhere for an explanation of why alcohols EI GC-MS always have a more prominent M-1 signal over a Parent chain signal--sometimes no parent signal at all.
One site says
http:...
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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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How can I identify the material of this mystery gear?
I have this small gear which has sat on my desk for a couple years. I can't remember where it originally came from or what material it's made out of, so I'm hoping you can help me solve this mystery.
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What is the most accurate way to determine the amount of water in a material from XRF and LOD-105 results?
this might seem like a silly question but I want to be sure. I have the results from an external laboratory for the bulk chemical composition (by XRF) and moisture (by Loss on Drying to 105 degrees ...
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False positive test for chloride ions during lab practical
In my highschool practical examination yesterday, I was given an inorganic salt to identify using chemical tests. The test I performed for the presence of chloride was to heat salt in a test tube with ...
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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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How to identify salts using mutual reactions
There are ten test tubes in the rack at your disposal (1 – 10) and each test tube contains one of the aqueous solutions of the following salts: $\ce{Na2SO4, AgNO3, KI, Ba(OH)2, NH4Cl, Ag2SO4, Pb(NO3)2,...
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Reactivity in my standard solution of Cu, P, Al, Ca, Fe, K, Mg, Mn, Na and S in 7,8% HNO3 and H2O2
I have a problem with my standard for ICP-OES. It contains the following elements Cu, P, Al, Ca, Fe, K, Mg, Mn, Na and S in a solution of 7,8% HNO3 and H2O2.
I cannot make it work for reading P and ...
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Equipment recommendation for atomic absorption spectroscopy (AAS) testing for mercury, lead, and cadmium
I work in a public health laboratory in a small mining town and we have the chance to buy equipment to test for lead and cadmium in wastewater, and mercury in not just wastewater, but also in blood, ...
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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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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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Detection of Nitrogen and Sulfur in Lassaigne's Test
In Lassaigne's test for the detection of nitrogen and/or sulfur in organic compounds, we prepare Lassaigne's extract. In this extract, NaCN is formed if nitrogen is present, and $\ce{Na2S}$ is formed ...
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Why are sulfites often ignored in soil studies?
From a document on soil chemistry that I am reading:
The acid-base potential of a soil takes soil pH, total sulfur (sulfides and sulfates), and neutralization potential into account to determine the ...
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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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battery using zinc, copper, and vinegar
I filed one side of a penny to reveal the zinc; then I bent the coin and dropped it into a cup of white vinegar. Shortly afterward, many tiny bubbles were forming on the zinc side. Later on, I noticed ...
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Measuring Rare Earth Element Concentration in a Solution
I am interested in repeating the experiment as detailed in this paper: Study on Rare Earth Elements Leaching from Magnetic Coal Fly Ash by Citric Acid
In the paper, coal fly ash is leached by citric ...
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Cant figure out whether Lithium or Strontium is in my substance? [closed]
So for uni I got a substance and I have to basically figure out which anions and cations are in it. I get two chances to guess otherwise I get a new substance and have to start from scratch.
Anyway ...
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P2O5 concentration % based on a 75% Phosphoric Acid Solution [closed]
I have a very poor chemical background, so please be indulgent in the case my question seems silly.
I need this clarification for a practical application:
If I want to obtain a P2O5 concentration of 4,...
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Why the electrode that is the electron source on a x-ray tube is called cathode? [closed]
In electrochemistry, the electrode that lose electrons and oxidizes is called anode. Why on an x-ray tube the electrode that lose electrons is called cathode?
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Where can I find any assay of common baking soda (for example Arm and Hammer or generic grocery store brands)?
I am looking for any assay of common baking soda, listing approximate percentages of impurities or trace elements for example potassium, boron, chloride, fluoride, etc.
For example my naive guess ...
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How much Na2O (from NaOH) do I add to sodium silicate with a weight ratio of SiO2/Na2O = 2.34 to get the solution to a weight ratio SiO2/Na2O = 1.9?
There is some confusion in industry as sodium silicate is made with NaOH but given a ratio with respect to Na2O (i.e. SiO2/Na2O not SiO2/NaOH). I presume it follows from this equation:
2NaOH -> ...
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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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Can we use silver nitrate to distinguish between chloride and carbonate salts?
Initially, we are given a solution containing two salts, they can be either carbonate or chloride salts (we do not know their composition initially).
Generally, $\ce{AgNO3}$ is used as a confirmatory ...
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Whatman 41 filter uses for? [closed]
I was reading a research article related to winter fog, so the researcher collected aerosols on Whatman 41 filters every 12h, and we know that Whatman 41 filters are usually used for Qualitative ...
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Chemical elements or compounds with yellowish white color [closed]
Are there chemical elements or compounds that have a yellowish white (cream) color in their natural state?
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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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Determining stoichiometry in ICP-OES data analysis
I have questions regarding data analysis for an inductively coupled plasma (ICP) experiment from a paper by Wang et al. [1].
The generic formula for the chemical compound is $\ce{Na_{2−x}Fe[Fe(CN)6]}$...
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A basic physical chemistry problem [closed]
I am a high school student and have just begin my classes(online). I just started physical chemistry but I know about moles, percentage composition, empirical formula. I haven't been able to solve ...
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Arsenic bound proteins confirmatory test
I want to confirm the presence of arsenic in some protein samples, apart from the marsh test can I use the following method?--
Arsenic is present as arsenic (III) ion in the samples. Hydrogen sulfide ...
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