সাঁচ:Chem molar mass/doc

This template calculates the molecular mass (or molar mass) of a chemical compound. It is designed to be embedded in infoboxes {{Infobox drug}} and {{Chembox}}, but it can be used in-line just as well.

Parameters

Use chemical symbols to compose the molecular formula: {{Chem molar mass|H=2|O=1}} (for H
2O) → 18.02 g·mol⁻¹

|round= by default the calculated number is rounded to 2 decimals.

|round=no will show all decimals:

{{Chem molar mass|Be=1|round=no}} → 9.0121831 g·mol⁻¹

|round=a number will round to that number of decimals

{{Chem molar mass|Be=1|round=4}} → 9.0122 g·mol⁻¹

|unit= changes the unit for the calculated result. The default unit is g·mol⁻¹.

{{Chem molar mass|H=2|O=1|unit=gram per mole}} → 18.02 gram per mole

The next parameters will always show:
|fixed= to enter a fixed (predefined) value+unit. It will overwrite any calculated value+unit.

|ref=<ref>some source</ref> will add the reference right after the unit.

|comment=Any textis added as a suffix, after a space and unedited (no brackets added etc.).

Example:

{{Chem molar mass|fixed=234.56 g·mol<sup>−1</sup>|ref=<ref>Some source</ref>|comment=My Comment}} → 234.56 g·mol⁻¹ My Comment

|sortable=yes, for use in sortable tables: will add a hidden sortable number, and omits the unit (see table below).

Blank parameter list

{{Chem molar mass | round = | unit = | fixed = | ref = | comment = | sortable= | catname = }}

{{Chem molar mass <!-- with 118 chemical symbols: -->|H= |He= |Li= |Be= |B= |C= |N= |O= |F= |Ne= |Na= |Mg= |Al= |Si= |P= |S= |Cl= |Ar= |K= |Ca= |Sc= |Ti= |V= |Cr= |Mn= |Fe= |Co= |Ni= |Cu= |Zn= |Ga= |Ge= |As= |Se= |Br= |Kr= |Rb= |Sr= |Y= |Zr= |Nb= |Mo= |Tc= |Ru= |Rh= |Pd= |Ag= |Cd= |In= |Sn= |Sb= |Te= |I= |Xe= |Cs= |Ba= |La= |Ce= |Pr= |Nd= |Pm= |Sm= |Eu= |Gd= |Tb= |Dy= |Ho= |Er= |Tm= |Yb= |Lu= |Hf= |Ta= |W= |Re= |Os= |Ir= |Pt= |Au= |Hg= |Tl= |Pb= |Bi= |Po= |At= |Rn= |Fr= |Ra= |Ac= |Th= |Pa= |U= |Np= |Pu= |Am= |Cm= |Bk= |Cf= |Es= |Fm= |Md= |No= |Lr= |Rf= |Db= |Sg= |Bh= |Hs= |Mt= |Ds= |Rg= |Cn= |Nh= |Lv= |Mc= |Fl= |Ts= |Og= | round = | unit = | fixed = | ref = | comment = | sortable= | catname = }}

Standard atomic weights used

Data sources (CIAAW)

Primarily, the atomic weights used here are defined by CIAAW [1]:

• "Standard Atomic Weights". Commission on Isotopic Abundances and Atomic Weights (CIAAW). 2015. http://www.ciaaw.org/atomic-weights.htm। আহৰণ কৰা হৈছে: 2015-09-20.  (68 elements)
• CIAAW also published additional lists in spreadsheet format (2013). It has additional conventional values for trade usage, and some background information on the numbers and calculations. (12 elements: B, Br, C, Cl, H, Li, Mg, N, O, S, Si, Tl).

Coplen, T.B.; Brand, W.A. (2013). "Atomic weights of the elements 2013 (xls)". CIAAW. http://www.ciaaw.org/publications.htm। আহৰণ কৰা হৈছে: 2015-05-26. 

• Some unstable elements can naturally occur, and so are listed (4 elements: Bi, Th, Pa, U)
• Additional values are those of the most stable isotopes, as given in List of chemical elements (34 elements). This source is not supported by the CIAAW publications.

See also: "Atomic weights of the elements 2013 (IUPAC Technical Report)". February 2016. doi:10.1515/pac-2015-0305. ISSN 0033-4545. https://www.degruyter.com/view/j/pac.2016.88.issue-3/pac-2015-0305/pac-2015-0305.xml। আহৰণ কৰা হৈছে: 2016-12-29. 

• Possolo, Antonio; van der Veen, Adriaan M. H.; Meija, Juris; Hibbert, D. Brynn (2018-01-04). "Interpreting and propagating the uncertainty of the standard atomic weights (IUPAC Technical Report)". doi:10.1515/pac-2016-0402. https://www.degruyter.com/view/j/pac.2018.90.issue-2/pac-2016-0402/pac-2016-0402.xml। আহৰণ কৰা হৈছে: 2018-09-23. 

Embedding in a template

The template is designed to be embedded in a template like {{Drugbox}}. The molecular formula can be entered like ...|H=2|O=1, and these values then are passed through to this subtemplate, together with the other parameters like |round=.

For this usage one extra parameter is available:
|catname=. A category name entered here, which will be used as maintenance category for articles that have both calculated and fixed input. These are two inputs for one data value. The maintenance task is to remove the |fixed= input (unless overwriting is intentional).

Know issue: uncertainty

Atomic weights are given with a precision and uncertainty, for example: 20.1797(6) for neon (more here).

Uncertainty

This template does not maintain the uncertainty (the bracketed part). When done correctly, the uncertainty could influence the result, especially when precision (number of decimals) is larger.

Rounding

This template usually does rounding on the calculated result, to 2 decimals by default:

For neon: {{Chem molar mass|Ne=1}} → 20.18 g·mol⁻¹

Two decimals is common practice for trade and most laboratory situations. However, rounding is set to more decimals, and the compounnd has atoms with less precision, the resulting number will be inaccurate (suggesting a wrong precision). For example strontium :

{{Chem molar mass|Sr=1|round=4}} → 87.62০০ g·mol⁻¹

Six elements have values ending with a final decimal being "0" (a zero), like Sn: 118.710. This value does not show for technical reasons (the calculation 'rounds them away'), but it does signify an extra precision. The six elements are Sn, Rh, Ge, Sb, Dy, Bi.

Calculate cumulative uncertainties

• [2], [3]

See also

• {{Chem molar mass/format}}
• {{Chem}} (formula)
• {{Atomic mass}}
• {{Molar mass}}