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Research draft

molar volume

vr.tr.molar-volume · XCT.REL

Let an agent handle molar volume by substance, conditions, calculation and use in chemistry, stating the reference conditions explicitly.

Thing Registry Cross-cutting context

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 handle molar volume by substance, conditions, calculation and use in chemistry, stating the reference conditions explicitly.

The volume occupied by one mole of a substance at a given temperature and pressure, measured in cubic metres per mole; for an ideal gas it is about 22.71 L/mol at 0 degC and 100 kPa, or 22.41 L/mol at 0 degC and 101.325 kPa.

What it is for: Relating amount of substance to volume in chemistry and engineering.

It can be compute molar volume from density and molar mass; use ideal gas molar volumes at stated conditions; correct for non-ideal behaviour; convert between mass, moles and volume.

Distinguishing features

Volume per mole

Depends on temperature and pressure

Near-constant for ideal gases at given conditions

Varies for liquids and solids

What it looks like

Not visible; a computed or tabulated quantity.

Physical character

ideal gas, 0 degC and 100 kPa: about 22.71 L/mol - IUPAC STP

ideal gas, 0 degC and 101.325 kPa: about 22.41 L/mol - older convention

How it is recognised

Units m3/mol or L/mol

Reference conditions such as STP

Specific volume is per unit mass instead

Related models

is a kind of - category

molar quantity and intensive quantity

is related to - relation

ideal gas law

is related to - quantities

density and molar mass

is contrasted with - per mass

specific volume

In practice

Families and kinds

molar volume of gases

molar volume of liquids

molar volume of solids

partial molar volume

Standards and regulation

IUPAC Green Book

ISO 80000-9

Failure modes and hazards

Using the wrong reference conditions

Applying ideal values to real gases at high pressure

Where this came from

wikidata · CC0 1.0

Drafted structure

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

Value Computation.

Conditions decide values.

Compute

From data.

Compute

Computation.

  1. What is the molar volume from density and molar mass? measurement
  2. In which units? definition

Conditions

Reference state.

Conditions

Reference conditions.

  1. Which temperature and pressure are assumed? definition
  2. Which STP convention is used? boundary
Gases Ideal and real.

Real gases deviate.

Ideal

Ideal gas law.

Ideal

Ideal gas.

  1. What is the ideal gas molar volume at these conditions? measurement
  2. Is the ideal approximation valid? boundary

Real

Corrections.

Real

Real gas.

  1. What correction, such as the compressibility factor, is needed? measurement
  2. From which equation of state? provenance
Condensed Liquids and solids.

Condensed phases vary.

Liquids

Values.

Liquids

Liquid molar volume.

  1. What is the molar volume of this liquid at this temperature? measurement
  2. From which data source? provenance

Mixtures

Partial molar volume.

Mixtures

Mixtures.

  1. Does mixing change the total volume? boundary
  2. How is partial molar volume used? definition
Teaching Learning.

Clear conventions help.

Explain

Simple terms.

Explain

Explanation.

  1. How can molar volume be explained with an example? action
  2. Which convention does the syllabus use? provenance

Errors

Common mistakes.

Errors

Common mistakes.

  1. Is an outdated STP value being used? boundary
  2. How can it be corrected? action

What the second pass must settle

  • Should partial molar volume be a separate entry?
  • How should reference conditions be recorded?
  • How should real-gas corrections be linked?