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Questions tagged [isotope]

This tag should only be applied where the effects are specifically related to variance in mass number with the same atomic number (existence of isotopes). Examples include: radioactivity and other nuclear properties, kinetic effects, specific relevance to spectroscopy (e.g., NMR, IR), isotope ...

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Temperature dependency on isotope fractionation

I have a question concerning isotopic fractionation. I am trying to explore the effect of temperature on isotopic fractionation. I know that isotopic fractionation is temperature dependent and it ...
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Raman spectrum of acid acetic with deuterium?

I have raman spectrums of 3 differents acetic acid in solution : $$CH_3COOH \qquad \qquad CH_3COOD \qquad \qquad CD_3COOD$$ All the following are hypothesis from me and I would like to know if it's ...
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Is an isobar the same as an isotope?

I am a little bit confused about what an isobar is. Its online definition is that it's an element with the same number of neutrons but a different number of protons from an element $\ce{X}$. To me, ...
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Francium has isotopes so how can its atomic mass be a whole number?

Why do francium, radon, radium, and actinium have whole numbers for average atomic mass even though they have isotopes? But then elements like beryllium, fluorine, and sodium are listed as having no ...
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Chemical equilibrium

In the Haber process, hydrogen and nitrogen are reacted to form ammonia. This reaction has a given equilibrium constant for the reaction at a given temperature. If we were to substitute hydrogen gas ...
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1answer
46 views

Can I expect 18O-hydroxide when adding slight amount of NaOH-16O to 18O-water?

In adding $\ce{^{16}O}$-sodium hydroxide to $\ce{^{18}O}$-water to get a $0.25\pu M$ solution, is the hydroxide in form of $\ce{^{16}O}$-hydroxide or $\ce{^{18}O}$-hydroxide? is there an oxygen ...
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1answer
442 views

What is [U-14C]-glucose?

In Helen Tweeddale's article,[1] they labelled metabolites of E. coli with [U-$^{14}$C]glucose. What sort of glucose is it? I understand they used isotope 14, which is radioactive but what does the U ...
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1answer
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Fluorine and fossils

They are now assisted by chemists who are able to fix dates through the analysis of pollen, radioactive carbon, and fluorine found in connection with fossils.. Here the text is talking about basic ...
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1answer
188 views

Why is the standard atomic weight of chlorine not a whole number? [duplicate]

Why is the standard atomic weight of chlorine, 35.5, not a whole number? Like for example, it could be exactly 35 or exactly 36. Please show the solution of formulae on how u reach to 35.5) with some ...
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2answers
65 views

Atomic weight = expected weight?

The atomic weight of an element, is it accurate to say that another way to think of it is the expected value of that element's weight if we were to sample one at random from the environment? Are man-...
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1answer
118 views

Which element has the highest binding energy per nucleon

The graph of binding energy per nucleon (Hyperphysics) seems to peak at Iron-56. However, Wikipedia says that Nickel-62 has the highest binding energy per nucleon of any known nuclide (8.7945 MeV). ...
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1answer
45 views

Making sulfate from elemental sulfur [closed]

I have $\approx\pu{2 g}$ of elemental sulfur that I need to convert to dissolved sulfate in DI water. What's the easiest lab chemistry that will get me there?
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1answer
48 views

Is there a blanket term for all variants (both nuclides and ions) of a chemical element?

I'm hoping to catalogue the various nuclides and oxidation states of an element but can't find a single term that describes them all, save for "chemical element variations". Is there a specific term ...
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1answer
267 views

How is phosphorus-32 produced?

I'm doing an assignment where I have to research a radioisotope of my choice. I decided to do phosphorus-32 and my assignment requires me to explain how the isotope is made. There is very minimal ...
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Effect of C13 vs. C12 reduced mass on specific vibrational modes

I understand that the reduced mass of C13 will be greater than for C12, and therefore its vibrational frequency will be lower, as it is inversely proportional to the reduced mass. However, I was ...
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1answer
96 views

Is water with oxygen-17 safe to drink? [closed]

Is it safe to drink and what else can it be used for?
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2answers
82 views

Does CHT=CHT have a geometric isomerism because of tritium atoms?

Is the radioisotope of hydrogen considered as a new atom? Can you detect it with an H NMR?
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33 views

Carbon 14 in organic chemistry [duplicate]

A small amount of natural carbon is $\ce{^{14}C}$. This is radioactive and decays to $\ce{^{14}N}$. This is exploited in radiocarbon dating. This $\ce{^{14}C}$ is taken up by living organisms. I ...
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2answers
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Do light and heavy water form an azeotrope?

(Interested in the general principle too, not just for water and its variants, but with particular emphasis on it.) When you distill a weak ethanol-in-water solution, you get a condensate that's ...
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1answer
138 views

Isotopic mass to density

I want to figure out/calculate the density ($\pu{g/cm3}$) of the various isotopes, here $\ce{^109Ag}$. I know it's isotopic mass is $\approx109$ and calculated the number of particles/gram. But I ...
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2answers
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Why is the probability for the signal at 160 in the bromine mass spectrum twice as high as for the signals at 158 and 162?

The mass spectrum in Bromine, with the molecules $\ce{^{158}Br2+}$, $\ce{^{160}Br2+}$ and $\ce{^{162}Br2+}$: As you can see, the $\ce{^{160}Br2+}$ is almost double in intensity compared to the $\ce{^{...
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1answer
1k views

How many peaks of HCl are found in a mass spectrum?

In a mass spectrometer some hydrogen chloride molecules will split into atoms. Chlorine has two isotopes. The hydrogen involved here is the isotope $\ce{^1_1H}$ only. How many peaks does a mass ...
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1answer
262 views

What is the difference between a time of flight mass spectrometer and a spectrometer that uses a magnetic field?

Traditional mass spectrometers used electromagnets to deflect isotopes of different masses which allowed only a certain isotope to reach the detector. But how is the TOF MS different besides the fact ...
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1answer
218 views

How many isotopologues of water are there?

If ordinary water molecules can contain any of the three hydrogen isotopes, $\ce{^1H}$, $\ce{^2H}$, $\ce{^3H}$, and any of the three oxygen isotopes, $\ce{^{16}O}$, $\ce{^{17}O}$, $\ce{^{18}O}$, how ...
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1answer
2k views

Why do higher-mass isotopes have higher melting and boiling points than lower-mass isotopes?

Different isotopes of the same element have the same number of electrons, so the nature of bonding between different isotopes of the same element should be the same, yet their melting points and ...
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1answer
432 views

Freezing point of oxygen-18 water

The freezing points of heavy water (3.8 °C) and tritiated water (4.49 °C) both seem to be well-known. I can't find anywhere that gives the freezing points of $\ce{H2^18O}$, $\ce{D2^18O}$, or $\ce{T2^...
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2answers
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Is it possible to find the ratio of isotopes only given the mean mass number?

Three isotopes of an element have mass numbers $(M)$, $(M+1)$ and $(M+2)$. If the mean mass number is $(M+0.5)$, then the ratio of the amounts of the three isotopes is? Let amount of $(M)$, $(M+1)$, ...
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0answers
30 views

Does the isotope of a polyvalent element affect which variable charge it has? [duplicate]

Doing a little side studying and this question arose: Does the isotope of a polyvalent element affect which variable charge it has? What I'm wondering is say for iron (Fe), which can have cations of ...
3
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2answers
54 views

Where can I find ranges of isotope abundances?

I'd like to know how much stable isotopes like $\ce{^{13}C}$, $\ce{^2H}$, $\ce{^{17}O}$ and $\ce{^{18}O}$ deviate from their natural abundances in the earth's crust among all possible compounds we may ...
8
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0answers
141 views

Why would a reaction favor one isotope over another?

In my instrumentation class last semester, we were asked to read a short paper. The paper described a technique for determining whether dinosaurs were cold-blooded or warm-blooded based on the amount ...
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1answer
179 views

Heavy-oxygen water production

It is easy to find information about heavy-hydrogen water production, but not about heavy-oxygen water. How is heavy-oxygen water commercially produced (for both heavier isotopes)?
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Can isotopes of a given element be represented by different symbols?

Can isotopes of any given element be represented using a completely different chemical symbol? What's the IUPAC's take on this? Sure, ordinarily you would add the isotope's mass as a superscript to ...
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Are stronger bonds always shorter?

This question relates to a few earlier questions I have seen on the site (particularly this one about the bond strength of heavier isotopes). Does a bond necessarily have to be shorter to be stronger? ...
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0answers
322 views

Best Radioactive Isotopes for Energy Generation [closed]

First off, this is research for a video game storyline, I like to be thorough. -- I am looking for the most efficient method of nuclear power generation which: Can survive for hundreds/thousands of ...
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1answer
207 views

Why are isotopically pure diamonds 50% more thermally conductive than other diamonds?

A laboratory grown type-IIa diamond (no nitrogen defects) has a lambda of $1800-2200~W/mK$, but an isotopically pure diamond of $\ce{^{12}C}$ can have up to $3320~W/mK$. Why are $\ce{^{12}C}$ ...
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Isotopic Dioxygen Raman Spectroscopy

Comment on the fact that $\ce{^{16}O-^{18}O}$ dioxygen leads to only one v($\ce{O-O}$) Raman active stretching frequency at $\mathrm{728~cm^{-1}}$. Isotopic substitution will make the molecule ...
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1answer
448 views

Meaning of m2 in the symbol for an isotope of an element

What does the notation $^{197\mathrm{m}2}\ce{Pb}$ mean? Specifically, the '$\mathrm{m}$2' part. I've found this and it appears to have something to do with charge distribution. The original notation ...
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1answer
282 views

If the half-life of an isotope exceeds the age of the Universe, then how is it measured?

According to this Wikipedia article, the half-life of Bismuth-209 is 19 billion billion years, which exceeds the age of the Universe by factor on the order of a billion. How is the half-life of an ...
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1answer
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Carbon-13 NMR for chloroform

I am slightly confused by what the spectrum would show for carbon-13 NMR of $\ce{CHCl3}$. My initial guess would be that the peak would be split by coupling to both the proton and the 3 chlorines, as ...
5
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2answers
120 views

Burning different isotope combinations of hydrogen and oxygen, how much does the energy vary?

In this comment I suggested that there would be a (very) small difference in energy released from burning a stoichiometric mixture of hydrogen and oxygen, depending on the isotopes, due to a slight ...
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1answer
383 views

How to specify a different isotope in the ORCA quantum chemistry program?

I would like to carry out a calculation using deuterium instead of hydrogen. I tried the following ORCA input file: ...
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1answer
546 views

Dipole Moment of Normal Water vs Heavy Water

The question is in the title itself. My guess: Higher for Normal water. My Reasoning: Internet told me Deuterium is more electronegative than Protium. So, there should be less difference between ...
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1answer
399 views

Why is Nitrogen 15 found almost exclusively in marine environments?

Prelude The following story was told to me earlier this summer Every year during October, the Pacific rain creates an ideal spawning condition for the wild Pacific salmon in the coastal forests of ...
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2answers
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Isotope pairs in different states at room temperature?

Does any pair of isotopes exist which are in different states at room temperature—either in isolation or as part of an otherwise-identical compound?
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1answer
82 views

Calculate the amount of substance of an isotope based on the percent composition

Calculate the amount of substance of $\ce{^37Cl}$ in a $\pu{42.3 g}$ sample of $\ce{Cl}$ containing $24.00\%~\ce{^37Cl}$ and $76.00\%~ \ce{^35Cl}.$ Given the atomic masses $m(\ce{Cl}) =\pu{35.45 amu}...
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2answers
341 views

Rounding of atomic weight isotopes

When we look at atomic mass, for example, $\ce{^134Ba}$ (barium) has a mass of $133.90 \,\mathrm{Da}$. Why is this rounded to $134 \,\mathrm{Da}$? This is shown in my book.
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1answer
104 views

Transparency and partially deuterated polymers

I've been skimming over the literature and have come into some conflicting information about the optical properties of partially deuterated polymers. From what I've seen, in general deuterated ...
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1answer
6k views

Can an Ion Isotope exist?

My question is simple, Can an isotope have a charge? i.e the number of protons and electrons defer in that atom. If it does exists, Is it right to call it an Ion Isotope? (or Isotope Ion) Thanks in ...
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2answers
523 views

How can we accurately carbon-date samples from La Brea?

TL;DR - given a sample of bone which has been encased in asphalt for tens of thousands of years and has become saturated with the asphalt, how can you get an accurate age for the specimen through ...
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0answers
57 views

Copper density modification

Can you increase the density of a material surface (metal) by surface treatment? For example commercial copper. If we take the ordinary OF copper (99.95%), I would expect not to have the tabulated 8....