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Research draft

chemical formula

vr.tr.chemical-formula · INF.MED

Let an agent explain chemical formulas and their kinds, relay notation rules and conventions from chemistry references, describe ionic formulas, formula units and formula weights, and distinguish formulas from chemical names, chemical equations and structural diagrams.

Thing Registry Information and virtual systems

Research draft, second pass

A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.

written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify

Researched by: Claude

Purpose and description

Let an agent explain chemical formulas and their kinds, relay notation rules and conventions from chemistry references, describe ionic formulas, formula units and formula weights, and distinguish formulas from chemical names, chemical equations and structural diagrams.

A notation using element symbols, numbers and other signs to express the composition of a chemical substance, from empirical and raw formulas giving element ratios and molecular formulas giving atom counts to structural formulas showing bonding, with conventions for ionic compounds and formula units, generalised salt and binary species notation, and the formula weight computed from the formula; chemical formulas follow IUPAC rules.

What it is for: Expressing chemical composition.

It can be explain formula kinds; relay notation rules; describe ionic conventions; distinguish related notations.

Distinguishing features

Symbolic

Several kinds

IUPAC rules

Basis for calculation

What it looks like

A string of element symbols with subscripts, such as H2O or NaCl.

Physical character

water: H2O note - molecular formula

sodium chloride: NaCl note - formula unit

Berzelius notation: 1813 year

How it is recognised

Symbolic expression of composition

Empirical and raw formula, molecular formula, ionic formula, formula unit, formula weight, binary species notation

Names are words; equations show reactions; structural diagrams draw bonds

Related models

is a kind of - in registry terms

notation

is governed by - rules

IUPAC nomenclature

is contrasted with - which shows reactions

chemical equation

was introduced by - in 1813

Jons Jacob Berzelius

In practice

Families and kinds

empirical and raw formulas

molecular formulas

structural and condensed formulas

ionic formulas and formula units

generalised formulas for salts and binary species

formula weight and molar mass calculations

Standards and regulation

IUPAC recommendations on formulas

Labelling regulations requiring formulas

Failure modes and hazards

Confusing empirical and molecular formulas

Misreading ionic formulas as molecules

Registry aliases mixing notation kinds and derived quantities

Also called

binary species formula notationgeneralized salt formulachemical formula weightIonic formulaformula unitraw formulamolecular formulaempirical formulacondensed formulacement chemist notationline formulaWiswesser line formulaestructural formulaskeletal formulaLewis structurestereochemical formulaCondensed structual formulaDashed structural formulaMarkush structure

Where this came from

wikidata · CC0 1.0

Source repository Registry entry point

Drafted structure

Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.

Understand What a chemical formula is.

Science.

Definition

Definition.

Definition

Definition.

  1. What is a chemical formula, and how does it differ from a name, an equation and a structural diagram? definition
  2. Is the question about a kind of formula, notation rules, ionic conventions or a calculation? boundary

Kinds

Kinds.

Kinds

Kinds.

  1. What are empirical, raw, molecular, structural and ionic formulas and formula units? definition
  2. Which entry fits the specific kind? action
Rules Notation rules.

Science.

IUPAC

IUPAC rules.

IUPAC

IUPAC.

  1. How do IUPAC rules order elements and write charges, hydrates and polymers? provenance
  2. Which references are standard? provenance

Ionic

Ionic and salt notation.

Ionic

Ionic.

  1. How are ionic compounds, generalised salts and binary species written? provenance
  2. Which sources are cited? provenance
Calculate Calculation.

Application.

Weight

Formula weight.

Weight

Weight.

  1. How is formula weight or molar mass computed from a formula? provenance
  2. Which entry fits molar mass? action

Analysis

From analysis to formula.

Analysis

Analysis.

  1. How are empirical and molecular formulas determined from analysis? provenance
  2. Which entry fits elemental analysis? action
Context History and computing.

Context.

History

History.

History

History.

  1. How did formula notation develop from Berzelius to modern conventions? provenance
  2. Which entry fits the history of chemistry? action

Computing

Computing.

Computing

Computing.

  1. How are formulas represented in databases and line notations such as SMILES? provenance
  2. Which entry fits SMILES? action

What the second pass must settle

  • Should formula unit and formula weight be separate primary entries?
  • How should chemistry references be linked?
  • The registry entry has merged aliases naming notation kinds and a derived quantity; should they be split off?
Draft as JSON