Report of the Committee on Atomic Weights of the American Chemical Society

Wichers, Edward

doi:10.1021/ja01130a001

Cited by 34 publications

(22 citation statements)

References 3 publications

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“…The molecular weight of carbon dioxide , the mass of which was used to detE'l'min e the amou nt of reaction , was taken as 44.010, 'from the 1952 table of international atomic wei ghLs [7 ]. 3 …”

Section: Units Of Energy and Molecula R W Eightsmentioning

confidence: 99%

Heats of combustion of liquid n-hexadecane, 1-hexadecene, n-decylbenzene, n-decylcyclohexane, n-decylcyclopentane, and the variation of heat of combustion with chain length

Fraser¹,

Prosen²

1955

J. RES. NATL. BUR. STAN.

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The heats of combust ion of five h ighl y purified long-chai n liquid h.vdrocil.rbon~ "'ere meas ured ",ith a bomb ca lorimeter . The calor imetric data y ield t he folloll'ing \'a lues for the h eat~ of combu s tiOIl , -t1 f1 cO(25° e), of the li quid hydrocarbon wilh gaseo us Ox.'·gE' 1l t o form gaseous car bon dioxide and liqu id water ; .l k ii ocalorie = 4.1840 kilo jo ul e. It i~ sholl' n th a, t , in th e liquid as \\'('11 as in the gascous s tat e, t he inc rc mc nt in the h(' a t of co mbu s ti o n (a nd hence in the heat of for matio n) prr (' H , group added in the li-alk.\·1 sid e chain is a co ns ta.nt excepL fo r the fi rst (\\'0 l1l e mben' of the . 'ie r ie s, and th a t (his incre me nt ha~ lh(' same value for eac h o f (hese s('r ies of com p ounds.

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Section: Units Of Energy and Molecula R W Eightsmentioning

confidence: 99%

Heats of combustion of liquid n-hexadecane, 1-hexadecene, n-decylbenzene, n-decylcyclohexane, n-decylcyclopentane, and the variation of heat of combustion with chain length

Fraser¹,

Prosen²

1955

J. RES. NATL. BUR. STAN.

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“…The CIAAW explained in 1951 that the "±0.003" represents the range of the atomic-weight values of sulfur due to natural variations in the abundance of its isotopes [12]. Coplen and Peiser [13,14] discuss the use of uncertainties in this context, and their interpretation.…”

Section: Expressions Of Uncertainty For Atomic Weightsmentioning

confidence: 99%

“…IUPAC's 1951 report on the Standard Atomic Weights for the first time included a reference to uncertainty, recommending the standard atomic weight of sulfur as 32.066 ± 0.003 [12]. The CIAAW explained in 1951 that the "±0.003" represents the range of the atomic-weight values of sulfur due to natural variations in the abundance of its isotopes [12].…”

Section: Expressions Of Uncertainty For Atomic Weightsmentioning

confidence: 99%

Interpreting and propagating the uncertainty of the standard atomic weights (IUPAC Technical Report)

Possolo

Veen

Meija

et al. 2018

Pure and Applied Chemistry

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Abstract:In 2009, the Commission on Isotopic Abundances and Atomic Weights (CIAAW) of the International Union of Pure and Applied Chemistry (IUPAC) introduced the interval notation to express the standard atomic weights of elements whose isotopic composition varies significantly in nature. However, it has become apparent that additional guidance would be helpful on how representative values should be derived from these intervals, and on how the associated uncertainty should be characterized and propagated to cognate quantities, such as relative molecular masses. The assignment of suitable probability distributions to the atomic weight intervals is consistent with the CIAAW's goal of emphasizing the variability of the atomic weight values in nature. These distributions, however, are not intended to reflect the natural variability of the abundances of the different isotopes in the earth's crust or in any other environment. Rather, they convey states of knowledge about the elemental composition of "normal" materials generally, or about specific classes of such materials. In the absence of detailed knowledge about the isotopic composition of a material, or when such details may safely be ignored, the probability distribution assigned to the standard atomic weight intervals may be taken as rectangular (or, uniform). This modeling choice is a reasonable and convenient default choice when a representative value of the atomic weight, and associated uncertainty, are needed in calculations involving atomic and relative molecular masses. When information about the provenance of the material, or other information about the isotopic composition needs to be taken into account, then this distribution may be non-uniform. We present several examples of how the probability distribution of an atomic weight or relative molecular mass may be characterized, and also how it may be used to evaluate the associated uncertainty.

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“…In the 1951-1955 TSAWs [8][9][10], only two footnotes appeared: a A value given in brackets denotes the mass number of the isotope of the most stable known isotope. b Because of natural variations in the relative abundances of the isotopes of sulfur the atomic weight of this element has a range of ±0.003.…”

Section: Past Footnotes and Annotations Of Atomic-weight Tablesmentioning

confidence: 99%

“…The identification of variations in abundances of stable isotopes upon atomic weights was recognized at the September 1951 meeting of the Commission on Atomic Weights of the International Union of Pure and Applied Chemistry (IUPAC), and an atomic-weight "range" was assigned to an element -an assignment of 32.066 ± 0.003 to sulfur [8]. In the 1951-1955 TSAWs [8][9][10], only two footnotes appeared: a A value given in brackets denotes the mass number of the isotope of the most stable known isotope.…”

Section: Past Footnotes and Annotations Of Atomic-weight Tablesmentioning

confidence: 99%

Review of footnotes and annotations to the 1949–2013 tables of standard atomic weights and tables of isotopic compositions of the elements (IUPAC Technical Report)

Coplen

Holden

2016

Pure and Applied Chemistry

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Abstract:The Commission on Isotopic Abundances and Atomic Weights uses annotations given in footnotes that are an integral part of the Tables of Standard Atomic Weights to alert users to the possibilities of quite extraordinary occurrences, as well as sources with abnormal atomic-weight values outside an otherwise acceptable range. The basic need for footnotes to the Standard Atomic Weights Table and equivalent annotations to the Table of Isotopic Compositions of the Elements arises from the necessity to provide users with information that is relevant to one or more elements, but that cannot be provided using numerical data in columns. Any desire to increase additional information conveyed by annotations to these Tables is tempered by the need to preserve a compact format and a style that can alert users, who would not be inclined to consult either the last full element-by-element review or the full text of a current Standard Atomic Weights of the Elements report. Since 1989, the footnotes of the Tables of Standard Atomic Weights and the annotations in column 5 of the Table of Isotopic Compositions of the Elements have been harmonized by use of three lowercase footnotes, "g", "m", and "r", that signify geologically exceptionally specimens ("g"), modified isotopic compositions in material subjected to undisclosed or inadvertent isotopic fractionation ("m"), and the range in isotopic composition of normal terrestrial material prevents more precise atomic-weight value being given ("r"). As some elements are assigned intervals for their standard atomic-weight values (applies to 12 elements since 2009), footnotes "g" and "r" are no longer needed for these elements.

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Report of the Committee on Atomic Weights of the American Chemical Society

Cited by 34 publications

References 3 publications

Heats of combustion of liquid n-hexadecane, 1-hexadecene, n-decylbenzene, n-decylcyclohexane, n-decylcyclopentane, and the variation of heat of combustion with chain length

Heats of combustion of liquid n-hexadecane, 1-hexadecene, n-decylbenzene, n-decylcyclohexane, n-decylcyclopentane, and the variation of heat of combustion with chain length

Interpreting and propagating the uncertainty of the standard atomic weights (IUPAC Technical Report)

Review of footnotes and annotations to the 1949–2013 tables of standard atomic weights and tables of isotopic compositions of the elements (IUPAC Technical Report)

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