SIST EN ISO 80000-9:2019
(Main)Quantities and units - Part 9: Physical chemistry and molecular physics (ISO 80000-9:2019)
Quantities and units - Part 9: Physical chemistry and molecular physics (ISO 80000-9:2019)
This document gives names, symbols, definitions and units for quantities of physical chemistry and
molecular physics. Where appropriate, conversion factors are also given.
Größen und Einheiten - Teil 9: Physikalische Chemie und Molekularphysik (ISO 80000-9:2019)
ISO 80000 9 enthält Benennungen, Formelzeichen und Definitionen für Größen und Einheiten der physikali¬schen Chemie und der Molekularphysik. Wo benötigt, sind auch Umrechnungsfaktoren aufgeführt.
Grandeurs et unités - Partie 9: Chimie physique et physique moléculaire (ISO 80000-9:2019)
Le présent document donne les noms, les symboles, les définitions et les unités des grandeurs de chimique physique et de physique moléculaire. Des facteurs de conversion sont également indiqués, s'il y a lieu.
Veličine in enote - 9. del: Fizikalna kemija in molekulska fizika (ISO 80000-9:2019)
Ta dokument podaja imena, simbole, definicije in enote za veličine s področja fizikalne kemije in molekulske fizike. Kadar je primerno, so navedeni tudi pretvorniki (pretvorni dejavniki).
General Information
Relations
Related Packages
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 80000-9:2019
01-december-2019
Nadomešča:
SIST EN ISO 80000-9:2013
Veličine in enote - 9. del: Fizikalna kemija in molekulska fizika (ISO 80000-9:2019)
Quantities and units - Part 9: Physical chemistry and molecular physics (ISO 80000-
9:2019)
Größen und Einheiten - Teil 9: Physikalische Chemie und Molekularphysik (ISO 80000-
9:2019)
Grandeurs et unités - Partie 9: Chimie physique et physique moléculaire (ISO 80000-
9:2019)
Ta slovenski standard je istoveten z: EN ISO 80000-9:2019
ICS:
01.060 Veličine in enote Quantities and units
07.030 Fizika. Kemija Physics. Chemistry
SIST EN ISO 80000-9:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN ISO 80000-9:2019
---------------------- Page: 2 ----------------------
SIST EN ISO 80000-9:2019
EN ISO 80000-9
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2019
EUROPÄISCHE NORM
ICS 01.060 Supersedes EN ISO 80000-9:2013
English Version
Quantities and units - Part 9: Physical chemistry and
molecular physics (ISO 80000-9:2019)
Grandeurs et unités - Partie 9: Chimie physique et Größen und Einheiten - Teil 9: Physikalische Chemie
physique moléculaire (ISO 80000-9:2019) und Molekularphysik (ISO 80000-9:2019)
This European Standard was approved by CEN on 5 May 2019.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 80000-9:2019 E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 80000-9:2019
EN ISO 80000-9:2019 (E)
Contents Page
European foreword . 3
2
---------------------- Page: 4 ----------------------
SIST EN ISO 80000-9:2019
EN ISO 80000-9:2019 (E)
European foreword
This document (EN ISO 80000-9:2019) has been prepared by Technical Committee ISO/TC 12
"Quantities and units" in collaboration with Technical Committee CEN/SS F02 “Units and symbols” the
secretariat of which is held by CCMC.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by April 2020, and conflicting national standards shall be
withdrawn at the latest by April 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 80000-9:2013.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 80000-9:2019 has been approved by CEN as EN ISO 80000-9:2019 without any
modification.
3
---------------------- Page: 5 ----------------------
SIST EN ISO 80000-9:2019
---------------------- Page: 6 ----------------------
SIST EN ISO 80000-9:2019
INTERNATIONAL ISO
STANDARD 80000-9
Second edition
2019-08
Quantities and units —
Part 9:
Physical chemistry and molecular
physics
Grandeurs et unités —
Partie 9: Chimie physique et physique moléculaire
Reference number
ISO 80000-9:2019(E)
©
ISO 2019
---------------------- Page: 7 ----------------------
SIST EN ISO 80000-9:2019
ISO 80000-9:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 80000-9:2019
ISO 80000-9:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
Bibliography .15
Index .16
© ISO 2019 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 80000-9:2019
ISO 80000-9:2019(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www. iso. org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www. iso.o rg/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www. iso
.org/iso/foreword. html.
This document was prepared by Technical Committee ISO/TC 12, Quantities and units, in collaboration
with Technical Committee IEC/TC 25, Quantities and units.
This second edition cancels and replaces the first edition (ISO 80000-9:2009), which has been
technically revised. It also incorporates the Amendment ISO 80000-9:2009/Amd. 1:2011.
The main changes compared to the previous edition are as follows:
— the table giving the quantities and units has been simplified;
— some definitions and the remarks have been stated physically more precisely.
A list of all parts in the ISO 80000 and IEC 80000 series can be found on the ISO and IEC websites.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www. iso. org/members. html.
iv © ISO 2019 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 80000-9:2019
ISO 80000-9:2019(E)
Introduction
In this document, symbols for substances are shown as subscripts, for example c , w , p for substance B.
B B B
Generally, it is advisable to put symbols for substances and their states in parentheses on the same line
as the main symbol, for example c(H SO ).
2 4
In the following, the letter s is used to denote the solid state, the letter l the liquid state, and the letter g
the gaseous state.
The symbol * used as a superscript means “pure”.
⊝
The plimsoll sign is used to denote a standard in general.
∗
EXAMPLE 1 μ (,Tp) for chemical potential of pure substance B concerning a mixture system including the
B
substance B.
−−11
EXAMPLE 2 C (H O,g,298,15K)=⋅33,58 JK ⋅mol for standard molar heat capacity at constant
m,p 2
pressure.
In an expression such as
V
m,B
ϕ =x
BB
xV
∑ i m,i
where
ϕ is the volume fraction of a particular substance B in a mixture of substances A, B, C, …;
B
x is the amount-of-substance fraction of i; and
i
V is the molar volume of the pure substance i, where all the molar volumes V , V ,V , .
m,i m,A m,B m,C
are taken at the same temperature and pressure,
the summation on the right-hand side is that over all the substances A, B, C, . of which a mixture is
composed, so that x =1 . Throughout the document sums are running over the respective index.
∑ i
Additional qualifying information on a quantity symbol may be added as a subscript or superscript (see
e.g. item 9-21) or in parentheses after the symbol.
© ISO 2019 – All rights reserved v
---------------------- Page: 11 ----------------------
SIST EN ISO 80000-9:2019
---------------------- Page: 12 ----------------------
SIST EN ISO 80000-9:2019
INTERNATIONAL STANDARD ISO 80000-9:2019(E)
Quantities and units —
Part 9:
Physical chemistry and molecular physics
1 Scope
This document gives names, symbols, definitions and units for quantities of physical chemistry and
molecular physics. Where appropriate, conversion factors are also given.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
Names, symbols, definitions and units for quantities used in physical chemistry and molecular physics
are given in Table 1.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
© ISO 2019 – All rights reserved 1
---------------------- Page: 13 ----------------------
SIST EN ISO 80000-9:2019
ISO 80000-9:2019(E)
2 © ISO 2019 – All rights reserved
Table 1 — Quantities and units used in physical chemistry and molecular physics
Item No. Quantity Unit Remarks
Name Symbol Definition
9-1 number of entities number of elementary entities of kind X in a system 1 The elementary entities must be specified
N()X ,
and can be atoms, molecules, ions, elec-
N trons, other particle, or a specified group
X
of such particles. It is important to always
give a precise specification of the entity
involved; this should preferably be done by
the empirical chemical formula of the mate-
rial involved.
9-2 amount of substance quotient of number N of specified elementary mol Amount of substance is one of the seven
n()X
entities of kind X (item 9-1) in a sample, and the base quantities in the International System
DEPRECATED: num-
of Quantities, ISQ (see ISO 80000-1).
Avogadro constant N (ISO 80000-1):
ber of moles
A
Elementary entities, such as molecules,
nN()XX= ()/N
A
atoms, ions, electrons, holes and other
quasi-particles, double bonds can be used.
It is necessary to specify precisely the
entity involved, e.g. atoms of hydrogen H
vs. molecules of hydrogen H , preferably by
2
giving the molecular chemical formula of
the material involved.
In the name “amount of substance”, the
words “of substance” could be replaced by
words specifying the substance concerned,
e.g. “amount of hydrogen chloride, HCl”, or
“amount of benzene, C H ”.
6 6
The name “number of moles” is often used
for “amount of substance”, but this is depre-
cated because the name of a quantity should
be distinguished from the name of the unit.
---------------------- Page: 14 ----------------------
SIST EN ISO 80000-9:2019
ISO 80000-9:2019(E)
© ISO 2019 – All rights reserved 3
Table 1 (continued)
Item No. Quantity Unit Remarks
Name Symbol Definition
9-3 relative atomic mass quotient of the average mass (ISO 80000-4) of atom 1 A similar quantity “relative molecular
A ()X
r
X and the unified atomic mass (ISO 80000-10) mass” can be defined for molecules.
EXAMPLE
A ()Cl ≈35,453,
r
A CO ≈44.
()
r 2
The relative atomic or relative molecular
mass depends on the nuclidic composition.
The International Union of Pure and Applied
Chemistry (IUPAC) accepts the use of the
special names “atomic weight” and “mo-
lecular weight” for the quantities “relative
atomic mass” and “relative molecular mass”,
respectively. The use of these traditional
names is deprecated.
9-4 molar mass for a pure substance X, quotient of mass m(X) g/mol
M X
()
(ISO 80000-4) and amount n of substance (item
−1
kg mol
9-2):
Mm= /n
3 −1
9-5 molar volume V for a pure substance, quotient of its volume V m mol
m
(ISO 80000−3) and amount n of substance (item
9-2):
VV= /n
m
9-6.1 molar internal U quotient of internal energy U (ISO 80000-5) and J/mol Molar quantities are normally only used with
m
energy amount n of substance (item 9-2): reference to pure substances.
2 −2 −1
kg m s mol
UU= /n
m
9-6.2 molar enthalpy H quotient of enthalpy H (ISO 80000-5) and amount J/mol Molar quantities are normally only used with
m
n of substance (item 9-2): reference to pure substances.
2 −2 −1
kg m s mol
HH= /n
m
---------------------- Page: 15 ----------------------
SIST EN ISO 80000-9:2019
ISO 80000-9:2019(E)
4 © ISO 2019 – All rights reserved
Table 1 (continued)
Item No. Quantity Unit Remarks
Name Symbol Definition
9-6.3 molar Helmholtz F quotient of the Helmholtz energy F (ISO 80000-5) J/mol Molar quantities are normally only used with
m
energy and amount n of substance (item 9-2): reference to pure substances.
2 −2 −1
kg m s mol
FF= /n
m
9-6.4 molar Gibbs energy G quotient of the Gibbs energy G (ISO 80000-5) and J/mol Molar quantities are normally only used with
m
amount n of substance (item 9-2): reference to pure substances.
2 −2 −1
kg m s mol
GG= /n
m
9-7 molar heat capacity C quotient of heat capacity C (ISO 80000-5) and J/(mol K) Conditions (constant pressure or volume etc.)
m
amount of substance n (item 9-2): must be specified.
2 −2 −1 −1
kg m s K mol
CC= /n
m
9-8 molar entropy S quotient of entropy S (ISO 80000-5) and amount n J/(mol K) Conditions (constant pressure or volume etc.)
m
of substance (item 9-2): must be specified.
2 −2 −1 −1
kg m s K mol
SS= /n
m
–3
9-9.1 particle n, (C) quotient of number N of particles (item 9-1) and m The term “number density” is also used.
concentration volume V (ISO 80000−3):
nN= /V
–3
9-9.2 molecular concen- C(X), C for substance X in a mixture, quotient of num- m
X
tration ber N of molecules of substance X and volume V
X
(ISO 80000−3) of the mixture:
CN= /V
XX
th
9-10 mass concentration γ , (ρ ) for substance X in a mixture, quotient of mass g/l Decided by the 16 CGPM (1979), both “l” and
X X
m (ISO 80000-4) of substance X and volume V “L” are allowed for the symbols for the litre.
X −3
kg m
(ISO 80000−3) of the mixture:
γ =mV/
XX
9-11 mass fraction w for substance X in a mixture, quotient of mass m 1
X X
(ISO 80000-4) of substance X and total mass m of
the mixture:
wm= /m
XX
---------------------- Page: 16 ----------------------
SIST EN ISO 80000-9:2019
ISO 80000-9:2019(E)
© ISO 2019 – All rights reserved 5
Table 1 (continued)
Item No. Quantity Unit Remarks
Name Symbol Definition
9-12.1 amount-of-substance c for substance X in a mixture, quotient of amount mol/l In chemistry, the name “amount-of-substance
X
concentration n of substance (item 9-2) of X and volume V concentration” is generally abbreviated to the
X –3
mol m
(ISO 80000−3) of the mixture: single word “concentration”, it being assumed
that the adjective “amount-of-substance” is
cn= /V
intended. For this reason, however, the word
XX
“mass” should never be omitted from the name
“mass concentration” in item 9-10.
th
Decided by the 16 CGPM (1979), both “l” and
“L” are allowed for the symbols for the litre.
th
9-12.2 standard amount-of- for substance X, one mole per litre mol/l Decided by the 16 CGPM (1979), both “l” and
c X
()
substance “L” are allowed for the symbols for the litre.
−3
mol m
concentration
9-13 amount-of-substance x , y for substance X in a mixture, quotient of amount of 1 For condensed phases, x is used, and for
X X X
fraction substance n (item 9-2) of X and total amount n of gaseous mixtures y may be used.
X X
substance (item 9-2) in the mixture:
mole fraction The unsystematic name “mole fraction” is
still used. However, the use of this name is
xn= /n
XX
deprecated.
For this quantity, the entity used to define
the amount of substance should always be
a single molecule for every species in the
mixture.
9-14 volume fraction for substance X, quotient of product of amount of ml/l Generally, the volume fraction is temperature
ϕ
X
substance fraction x (item 9-13) of X and molar dependent.
X
1
volume V (item 9-5) of the pure substance X at
m,X th
Decided by the 16 CGPM (1979), both “l” and
the same temperature (ISO 80000-5) and pres-
“L” are allowed for the symbols for the litre.
sure(ISO 80000-4), and sum over all substances
i of products of amount-of-substance fractions x
i
(item 9-13) of substance i and their molar volumes
V (item 9-5):
m,i
xV
Xm,X
ϕ =
X
xV
∑ iim,
i
---------------------- Page: 17 ----------------------
SIST EN ISO 80000-9:2019
ISO 80000-9:2019(E)
6 © ISO 2019 – All rights reserved
Table 1 (continued)
Item No. Quantity Unit Remarks
Name Symbol Definition
9-15 molality b , m quotient of amount of substance (item 9-2) of solute B mol/kg The alternative symbol m should be avoid-
B B B
and mass m (ISO 80000-4) of the solvent substance A ed in situations where it might be mistaken
A
b = n /m for the mass of substance B. However, the
B B A
symbol m is much more commonly used
B
than the symbol b for molality, despite the
B
possible confusion with mass.
9-16 latent heat of phase C energy (ISO 80000-5) necessary to
...
SLOVENSKI STANDARD
oSIST prEN ISO 80000-9:2017
01-marec-2017
9HOLþLQHLQHQRWH GHO )L]LNDOQDNHPLMDLQPROHNXOVNDIL]LND ,62',6
Quantities and units - Part 9: Physical chemistry and molecular physics (ISO/DIS 80000-
9:2017)
Größen und Einheiten - Teil 9: Physikalische Chemie und Molekularphysik (ISO/DIS
80000-9:2017)
Grandeurs et unités - Partie 9: Chimie physique et physique moléculaire (ISO/DIS 80000
-9:2017)
Ta slovenski standard je istoveten z: prEN ISO 80000-9
ICS:
01.060 9HOLþLQHLQHQRWH Quantities and units
07.030 Fizika. Kemija Physics. Chemistry
oSIST prEN ISO 80000-9:2017 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 80000-9:2017
---------------------- Page: 2 ----------------------
oSIST prEN ISO 80000-9:2017
DRAFT INTERNATIONAL STANDARD
ISO/DIS 80000-9
ISO/TC 12 Secretariat: SIS
Voting begins on: Voting terminates on:
2017-01-03 2017-03-27
Quantities and units —
Part 9:
Physical chemistry and molecular physics
Grandeurs et unités —
Partie 9: Chimie physique et physique moléculaire
ICS: 01.060
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
This draft is submitted to a parallel vote in ISO and in IEC.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 80000-9:2017(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2017
---------------------- Page: 3 ----------------------
oSIST prEN ISO 80000-9:2017
ISO/DIS 80000-9:2017(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 80000-9:2017
ISO/DIS 80000-9:2017(E)
Contents Page
Foreword . iv
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Names, symbols, and definitions . 1
4 Quantities, units and definitions . 0
Annex A (normative) pH . 0
Bibliography. 2
© ISO 2017 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 80000-9:2017
ISO/DIS 80000-9:2017(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has
been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of
ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity asses sment,
as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 12, Quantities and units
This third edition cancels and replaces the second edition (2013), of which has been technically revised.
ISO 80000 consists of the following parts.
Part 1: General
Part 2: Mathematics
Part 3: Space and time
Part 4: Mechanics
Part 5: Thermodynamics
Part 7: Light and radiation
Part 8: Acoustics
Part 9: Physical chemistry and molecular physics
Part 10: Atomic and nuclear physics
Part 11: Characteristic numbers
Part 12: Condensed matter physics
IEC 80000 consists of the following parts, under the general title Quantities and units:
iv © ISO 2017 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 80000-9:2017
ISO/DIS 80000-9:2017(E)
Part 6: Electromagnetism
Part 13: Information science and technology
1
Part 14: Telebiometrics related to human physiology
1
being replaced by ISO/IEC 80003 series
© ISO 2017 – All rights reserved v
---------------------- Page: 7 ----------------------
oSIST prEN ISO 80000-9:2017
ISO/DIS 80000-9:2017(E)
Introduction
0.1 Arrangements of the tables
The tables of quantities and units in this International Standard are arranged so that the quantities and the
units are presented on the same page.
All units between two full lines on the right-hand pages belong to the quantities between the corresponding
full lines on the left-hand pages.
Where the numbering of an item has been changed in the revision of a part of last edition, the number in the
preceding edition is shown in parentheses on the left-hand page under the new number for the quantity; a
dash is used to indicate that the item in question did not appear in the preceding edition.
0.2 Quantities
The names in English and in French of the most important quantities within the field of this International
Standard are given together with their symbols and, in most cases, their definitions. These names and
symbols are recommendations. The definitions are given for identification of the quantities in the
International System of Quantities (ISQ), listed on the left-hand pages of the table; they are not intended to
be complete.
⃗⃗
⃗⃗
The scalar, vectorial or tensorial character of quantities is pointed out using symbols with arrows like 𝑣⃗, 𝑇 or
subscripts like 𝑣 𝑇 especially when this is needed for the definitions.
𝑖 𝑖𝑗
In most cases only one name and only one symbol for the quantity are given; where two or more names or
two or more symbols are given for one quantity and no special distinction is made, they are on an equal
footing. When two types of italic letters exist (for example as with 𝜃 and 𝜗; 𝜑 and 𝜙; a and 𝑎; 𝑔 and g; 𝜅 and
𝜘) only one of these is given. This does not mean that the other is not equally acceptable. It is recommended
that such variants should not be given different meanings. A symbol within parentheses implies that it is a
reserve symbol, to be used when, in a particular context, the main symbol is in use with a different meaning.
In this English edition, the quantity names in French are printed in an italic font, and are preceded by fr. The
gender of the French name is indicated by (m) for masculine and (f) for feminine, immediately after the noun
in the French name.
0.3 Units
0.3.1 General
The names of units and their definitions are given in Part 1, General. Unit names are language-dependent,
but the symbols are international and the same in all languages. For further information, see the SI Brochure
(8th edition 2006) from BIPM and ISO 80000-1.
0.3.2 Remark on units for quantities of dimension one, or dimensionless quantities
The coherent unit for any quantity of dimension one, also called a dimensionless quantity, is the number one,
symbol 1. When the value of such a quantity is expressed, the unit symbol 1 is generally not written out
explicitly.
EXAMPLE 1 Refractive index 𝑛 = 1,53 × 1 = 1,53
vi © ISO 2017 – All rights reserved
---------------------- Page: 8 ----------------------
oSIST prEN ISO 80000-9:2017
ISO/DIS 80000-9:2017(E)
Prefixes shall not be used to form multiples or submultiples of this unit. Instead of prefixes, powers of 10 are
recommended.
3
EXAMPLE 2 Reynolds number 𝑅𝑒 = 1,32 × 10
Considering that plane angle is generally expressed as the ratio of two lengths and solid angle as the ratio of
two areas, in 1995 the CGPM specified that, in the SI, the radian, symbol rad, and steradian, symbol sr, are
dimensionless derived units. This implies that the quantities plane angle and solid angle are considered as
derived quantities of dimension one. The units radian and steradian are thus equal to one; they may either
be omitted, or they may be used in expressions for derived units to facilitate distinction between quantities
of different kinds but having the same dimension.
0.4 Numerical statements in this International Standard
The sign = is used to denote “is exactly equal to”, the sign ≈ is used to denote “is approximately equal to”,
and the sign : = is used to denote “is by definition equal to”.
Numerical values of physical quantities that have been experimentally determined always have an
associated measurement uncertainty. This uncertainty should always be specified. In this International
Standard, the magnitude of the uncertainty is represented as in the following example.
( )
EXAMPLE 𝑙 = 2,347 82 32 m
( )
In this example, 𝑙 = 𝑎 𝑏 m, the numerical value of the uncertainty 𝑏 indicated in parentheses is assumed to
apply to the last (and least significant) digits of the numerical value 𝑎 of the length 𝑙. This notation is used
when 𝑏 represents one standard uncertainty (estimated standard deviation) in the last digits of 𝑎. The
numerical example given above may be interpreted to mean that the best estimate of the numerical value of
the length 𝑙 (when 𝑙 is expressed in the unit metre) is 2,347 82(32) and that any value of 𝑙 between
2,347 82 − 0,000 32 m and 2,347 82 − 0,000 32 m with a probability determined by the standard
uncertainty 0,000 32 m and the probability distribution of the values of 𝑙 can be attributed to the measurand
(see JCGM 100:2008, Annex D).
0.5 Special remarks
In this part of ISO 80000, symbols for substances are shown as subscripts, for example 𝑐 , 𝑤 , 𝑝 for
B B B
substance B.
Generally, it is advisable to put symbols for substances and their states in parentheses on the same line as
the main symbol, for example 𝑐(H SO ).
2 4
In the following the letter s is used to denote the solid state, the letter l the liquid state, and the letter g the
gaseous state.
The superscript ∗ is used to mean “pure”. The superscript ° is used to mean “standard”.
The plimsoll sign ⊝ is used to denote a standard in general. The degree sign ° can also be used for this.
∗
EXAMPLE 1 𝜇 (T,P) for chemical potential of pure substance B concerning a mixture system including
𝐵
the substance B.
−1 −1
∘
EXAMPLE 2 𝐶 (H O, g, 298,15 K)=33,58 J ∙ K ∙ mol for standard molar heat capacity at constant
2
m, 𝑝
pressure.
© ISO 2017 – All rights reserved vii
---------------------- Page: 9 ----------------------
oSIST prEN ISO 80000-9:2017
ISO/DIS 80000-9:2017(E)
𝑉
m, B
ln an expression such as 𝜑 = 𝑥 𝑉 , where 𝜑 denotes the volume fraction of a particular substance B
B B m,𝑖 B
∑𝑥
i
in a mixture of substances A, B, C, …, where 𝑥 denotes the amount-of-substance fraction of 𝑖 and 𝑉 the
i m,𝑖
molar volume of the pure substance 𝑖, and where all the molar volumes 𝑉 , 𝑉 , 𝑉 , . are taken at the
m,A m,B m,C
same temperature and pressure, the summation on the right-hand side is that over all the substances A, B, C,
... of which a mixture is composed, so that ∑𝑥 = 1. Throughout the document sums are running over the
i
respective index.
Additional qualifying information on a quantity symbol may be added as a subscript or superscript (item 9-
21) or in parentheses after the symbol.
viii © ISO 2017 – All rights reserved
---------------------- Page: 10 ----------------------
oSIST prEN ISO 80000-9:2017
DRAFT INTERNATIONAL STANDARD ISO/DIS 80000-9:2017(E)
Quantities and units — Part 9: Physical chemistry and molecular
physics
1 Scope
ISO 80000-9 gives names, symbols, and definitions for quantities and units of physical chemistry and
molecular physics. Where appropriate, conversion factors are also given.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 80000-3:2006, Quantities and units — Part 3: Space and time
ISO 80000-4:2006, Quantities and units — Part 4: Mechanics
ISO 80000-5:2007, Quantities and units — Part 5: Thermodynamics
IEC 80000-6:2008, Quantities and units — Part 6: Electromagnetism
JCGM 100:2008, Evaluation of measurement data – Guide to the expression of uncertainty in measurement
3 Names, symbols, and definitions
The names, symbols, and definitions for quantities and units of physical chemistry and molecular physics are
given on the following pages.
© ISO 2017 – All rights reserved
1
---------------------- Page: 11 ----------------------
oSIST prEN ISO 80000-9:2017
DRAFT INTERNATIONAL STANDARD ISO/DIS 80000-9:2017(E)
4 Quantities, units and definitions
Quantity Unit
Item
Remarks
No.
Name Symbol Definition Symbol
9-1 number of entities N(X), 𝑁 number of elementary entities of kind X in a system 1
The elementary entities must be
X
specified and may be atoms,
molecules, ions, electrons, other
particle, or specified groups of
such particles. It is important to
always give a precise
specification of the entity
involved; this should preferably
be done by the empirical
chemical formula of the material
involved.
9-2 amount of substance 𝑛(X) mol
As an elementary quantity,
quotient of number 𝑁 of specified elementary entities (item 9-1)
entities like molecules, atoms,
in a sample, and Avogadro constant 𝑁 (item 1-X);
A
ions, electrons, holes and other
( )
𝑛 X = 𝑁(X)/𝑁 ,
A
quasi-particles, double bonds,
etc. can be used. It is necessary
to specify precisely the entity
involved, e.g. atoms of hydrogen
H vs. molecules of hydrogen H2,
preferably by giving the
molecular chemical formula of
the material involved
In the name “amount of
substance”, the words “of
© ISO 2017 – All rights reserved
0
---------------------- Page: 12 ----------------------
oSIST prEN ISO 80000-9:2017
ISO/DIS 80000-9:2017(E)
Quantity Unit
Item
Remarks
No.
Name Symbol Definition Symbol
substance” could be replaced by
words specifying the substance
concerned, e.g. “amount of
hydrogen chloride, HCl”, or
“amount of benzene, C H ”.
6 6
The name “number of moles” is
often used for “amount of
substance”, but this is
deprecated because the name of
a quantity should be
distinguished from the name of
the unit.
9-3.1 relative atomic mass 𝐴 (X) 1 EXAMPLE 𝐴 (Cl)≈35,453
ratio of the average mass (item 4-1) per atom of an element to
r r
12
1/12 of the mass of an atom of the nuclide C
The relative atomic or relative
molecular mass depends on the
nuclidic composition.
The International Union of Pure
and Applied Chemistry (IUPAC)
accepts the use of the special
names “atomic weight” and
“molecular weight” for the
quantities “relative atomic
mass” and “relative molecular
mass”, respectively. The use of
these traditional names is
deprecated.
9-3.2 relative molecular mass 𝑀 (X) ratio of the average mass per molecule or specified entity of a
r
12
substance to 1/12 of the mass of an atom of the nuclide C
© ISO 2017 – All rights reserved
1
---------------------- Page: 13 ----------------------
oSIST prEN ISO 80000-9:2017
ISO/DIS 80000-9:2017(E)
Quantity Unit
Item
Remarks
No.
Name Symbol Definition Symbol
-1
9-4 molar mass 𝑀(X)
for a pure sample, quotient of mass 𝑚(X) (item 4-1) and amount 𝑛
g mol
of substance (item 9-2):
𝑀 ≔ 𝑚/𝑛
-1
kg mol
3 -1
9-5 molar volume 𝑉
quotient of its volume V (item 3-4) and amount n of substance
m mol
m
(item 9-1):
𝑉 ≔ 𝑉/𝑛
m
9-6.1 molar internal energy 𝑈 quotient of internal energy 𝑈 (item 5-20.2) and amount 𝑛 of J/mol Molar quantities are normally
m
substance (item 9-1): only used with reference to pure
𝑈 : = 𝑈/𝑛 substances
m
9-6.2 molar enthalpy 𝐻
quotient of enthalpy 𝐻 (item 5-20.3) and amount 𝑛 of substance
m
(item 9-1):
𝐻 : = 𝐻/𝑛
m
9-6.3 molar Helmholz energy 𝐹
quotient of Helmholtz energy 𝐹 (item 5-20.4) and amount 𝑛 of
m
substance (item 9-1):
𝐹 : = 𝐹/𝑛
m
9-6.4 molar Gibbs energy 𝐺 quotient of Gibbs energy 𝐺 (item 5-20.5) and amount 𝑛 of
m
substance (item 9-1)
𝐺 : = 𝐺/𝑛
m
9-7 molar heat capacity 𝐶 quotient of heat capacity (item 5-15) and amount of substance 𝑛 J/(mol · K) Conditions (constant pressure or
m
(item 9-1): volume etc.) must be specified.
𝐶 : = 𝐶/𝑛
m
9-8 molar entropy 𝑆 J/(mol · K)
quotient of entropy 𝑆 (item 5-18) and amount 𝑛 of substance (item
m
9-1):
𝑆 : = 𝑆/𝑛
m
–3
9-9.1 particle concentration 𝑛, (𝐶)
quotient of number 𝑁 of particles (item 9-1) and volume 𝑉 The term "number density" is
m
© ISO 2017 – All rights reserved
2
---------------------- Page: 14 ----------------------
oSIST prEN ISO 80000-9:2017
ISO/DIS 80000-9:2017(E)
Quantity Unit
Item
Remarks
No.
Name Symbol Definition Symbol
(item 3-4): also used.
𝑛: = 𝑁/𝑉
9-9.2 C(X), C
molecular X for substance X, quotient of number 𝑁 of molecules of X and
X
concentration volume 𝑉 (item 3-4) of the mixture:
𝐶 = 𝑁 /𝑉
X X
th
9-10 mass concentration 𝛾 , (𝜌 ) g/l
for substance X, quotient of mass 𝑚 (item 4-1) of substance B and Decided by the 16 CGPM (1979)
B B
B
volume 𝑉 (item 3-4) of the mixture: both "l" and "L" are allowed for
3
kg/m
𝛾 : = 𝑚 /𝑉 the symbols for the litre.
B B
9-11 mass fraction 𝑤 1
for substance X, fraction of mass 𝑚 (item 4-1) of substance B and
B
B
total mass 𝑚 of the mixture:
𝑤 : = 𝑚 /𝑚
B B
3
9-12.1 𝑐
amount-of-substance for substance B, quotient of amount 𝑛 of substance (item 9-2) of B In chemistry, the name “amount-
B mol/m ,
B
concentration and volume 𝑉 (item 3-4) of the mixture: of-substance concentration” is
mol/l
𝑐 : = 𝑛 /𝑉 generally abbreviated to the
B B
single word “concentration”, it
being assumed that the adjective
“amount-of-substance” is
intended. For this reason,
however, the word “mass”
should never be omitted from
the name “mass concentration”
in 9-11.2.
⊝
9-12.2 standard amount-of- 𝑐 (X) for substance X, one mole per litre mol/l
substance
concentration
9-13 𝑥 , 𝑦 1
amount-of-substance for substance X, fraction of amount of substance 𝑛 (item 9-2) of B For condensed phases, 𝑥 is used,
B B
B B
and total amount 𝑛 of substance (item 9-2) in the mixture and for gaseous mixtures 𝑦 may
B
© ISO 2017 – All rights reserved
3
---------------------- Page: 15 ----------------------
oSIST prEN ISO 80000-9:2017
ISO/DIS 80000-9:2017(E)
Quantity Unit
Item
Remarks
No.
Name Symbol Definition Symbol
fraction 𝑥 : = 𝑛 /𝑛 be used.
B B
The unsystematic name “mole
fraction” is still used. However,
the use of this name is
deprecated.
For this quantity, the entity used
to define the amount of
substance should always be a
single molecule for every
species in the mixture.
9-14 volume fraction 𝜑 mol/mol 𝜑 is temperature dependent.
for substance X, fraction of product of amount of substance fraction
X X
𝑥 (item 9-13) of X and molar volume 𝑉 (item 9-5) of the pure
X m, X ml/l
substance X at the same temperature and pressure, and sum over
1
all substances 𝑖 of pr
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.