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Part 9: Physical Chemistry

Atomic and molecular physics

62 entries· Edition 2019FR→ About this part

9-1number of entities

N (X)

N_{X}

1

·one

number of elementary entities of kind in a system

9-2amount of substance, DEPRECATED: number of moles

9-2

amount of substance, DEPRECATED: number of moles

n (X)

m o l

·mole

quotient of number of specified elementary entities of kind (t9-1) in a sample, and the Avogadro constant (iso80000-1):

9-3relative atomic mass

9-3

relative atomic mass

A_{r} (X)

1

·one

quotient of the average mass (iso80000-4) of atom and the unified atomic mass (iso80000-10)

9-4molar mass

9-4

molar mass

M (X)

\frac{g}{m} o l

k g \cdot m o l^{- 1}

·gram per mole, kilogram per mole

for a pure substance , quotient of mass (iso80000-4) and amount of substance (t9-2):

9-5molar volume

9-5

molar volume

V_{m}

m^{3} \cdot m o l^{- 1}

·cubic metre per mole

for a pure substance, quotient of its volume (iso80000-3) and amount of substance (t9-2):

9-6molar internal energy

9-6.1

molar internal energy

U_{m}

\frac{J}{m} o l

k g \cdot m^{2} \cdot s^{- 2} \cdot m o l^{- 1}

·joule per mole, kilogram square metre per second squared mole

quotient of internal energy (iso80000-5) and amount of substance (t9-2):

9-6.2

molar enthalpy

H_{m}

\frac{J}{m} o l

k g \cdot m^{2} \cdot s^{- 2} \cdot m o l^{- 1}

·joule per mole, kilogram square metre per second squared mole

quotient of enthalpy (iso80000-5) and amount of substance (t9-2):

9-6.3

molar Helmholtz energy

F_{m}

\frac{J}{m} o l

k g \cdot m^{2} \cdot s^{- 2} \cdot m o l^{- 1}

·joule per mole, kilogram square metre per second squared mole

quotient of the Helmholtz energy (iso80000-5) and amount of substance (t9-2):

9-6.4

molar Gibbs energy

G_{m}

\frac{J}{m} o l

k g \cdot m^{2} \cdot s^{- 2} \cdot m o l^{- 1}

·joule per mole, kilogram square metre per second squared mole

quotient of the Gibbs energy (iso80000-5) and amount of substance (t9-2):

9-7molar heat capacity

9-7

molar heat capacity

C_{m}

\frac{J}{m o l \cdot K}

k g \cdot m^{2} \cdot s^{- 2} \cdot K^{- 1} \cdot m o l^{- 1}

·joule per mole kelvin, kilogram square metre per second squared kelvin mole

quotient of heat capacity (iso80000-5) and amount of substance (t9-2):

9-8molar entropy

9-8

molar entropy

S_{m}

\frac{J}{m o l \cdot K}

k g \cdot m^{2} \cdot s^{- 2} \cdot K^{- 1} \cdot m o l^{- 1}

·joule per mole kelvin, kilogram square metre per second squared kelvin mole

quotient of entropy (iso80000-5) and amount of substance (t9-2):

9-9particle concentration

9-9.1

particle concentration

n

(C)

m^{- 3}

·per cubic metre

quotient of number of particles (t9-1) and volume (iso80000-3):

9-9.2

molecular concentration

C (X)

C_{X}

m^{- 3}

·per cubic metre

for substance in a mixture, quotient of number of molecules of substance and volume (iso80000-3) of the mixture:

9-10mass concentration

9-10

mass concentration

γ_{X}

(ρ_{X})

\frac{g}{l}

k g \cdot m^{- 3}

·gram per litre, kilogram per cubic metre

for substance in a mixture, quotient of mass (iso80000-4) of substance and volume (iso80000-3) of the mixture:

9-11mass fraction

9-11

mass fraction

w_{X}

1

·one

for substance in a mixture, quotient of mass (iso80000-4) of substance and total mass of the mixture:

9-12amount-of-substance concentration

9-12.1

amount-of-substance concentration

c_{X}

m o \frac{l}{l}

m o l \cdot m^{- 3}

·mole per litre, mole per cubic metre

for substance in a mixture, quotient of amount of substance (t9-2) of and volume (iso80000-3) of the mixture

9-12.2

standard amount-of-substance concentration

c^{& # 8854;} (X)

m o \frac{l}{l}

m o l \cdot m^{- 3}

·mole per litre, mole per cubic metre

for substance , one mole per litre

9-13amount-of-substance fraction, mole fraction

9-13

amount-of-substance fraction, mole fraction

x_{X}

y_{X}

1

·one

for substance in a mixture, quotient of amount of substance (t9-2) of and total amount of substance (t9-2) in the mixture:

9-14volume fraction

9-14

volume fraction

φ_{X}

m \frac{l}{l}

1

·millilitre per litre, one

for substance , quotient of product of amount of substance fraction (t9-13) of and molar volume (t9-5) of the pure substance at the same…

9-15molality

9-15

molality

b_{B}

m_{B}

m o \frac{l}{k} g

·mole per kilogram

quotient of amount of substance (t9-2) of solute and mass (iso80000-4) of the solvent substance

9-16latent heat of phase transition, enthalpy of phase transition

9-16

latent heat of phase transition, enthalpy of phase transition

C_{pt}

J

k g \cdot m^{2} \cdot s^{- 2}

·joule, kilogram square metre per second squared

energy (iso80000-5) necessary to be added or subtracted isothermally and isobarically to a system to completely undergo the phase transition

9-17chemical potential <chemistry>

9-17

chemical potential

μ_{X}

\frac{J}{m} o l

k g \cdot m^{2} \cdot s^{- 2} \cdot m o l^{- 1}

·joule per mole, kilogram square metre per second squared mole

partial derivative of the Gibbs energy (iso80000-5) with respect to amount of substance (t9-2) at constant temperature (iso80000-5) and…

9-18absolute activity

9-18

absolute activity

λ_{X}

1

·one

for substance , exponential of quotient of chemical potential of substance (t9-17), and product of molar gas constant (t9-37.1) and…

9-19partial pressure

9-19

partial pressure

p_{X}

P a

k g \cdot m^{- 1} \cdot s^{- 2}

·pascal, kilogram per metre second squared

for substance in a gaseous mixture, product of amount-of-substance fraction of substance (t9-13) and total pressure (iso80000-4):

9-20fugacity

9-20

fugacity

{\tilde{p}}_{X}

P a

k g \cdot m^{- 1} \cdot s^{- 2}

·pascal, kilogram per metre second squared

for substance , quantity proportional to the absolute activity, (t9-18), the proportionality factor, which is a function of temperature…

9-21standard chemical potential

9-21

standard chemical potential

μ_{B}^{& # 8854;}

μ^{& # 8854;}

\frac{J}{m} o l

k g \cdot m^{2} \cdot s^{- 2} \cdot m o l^{- 1}

·joule per mole, kilogram square metre per second squared mole

for substance , value of the chemical potential (t9-17) at specified standard conditions

9-22activity factor

9-22

activity factor

f_{X}

1

·one

for substance in a liquid or a solid mixture, quotient of absolute activity (t9-18) of substance and the product of absolute activity of…

9-23standard absolute activity <in a mixture>

9-23

standard absolute activity

λ_{X}^{& # 8854;}

1

·one

for substance in a liquid or a solid mixture, absolute activity (t9-18) of the pure substance at the same temperature (iso80000-5) but at…

9-24activity of solute, relative activity of solute

9-24

activity of solute, relative activity of solute

a_{X}

a_{m,X}

1

·one

for a solute in a solution, quantity proportional to the absolute activity, (t9-18), the proportionality factor, which is a function of…

9-25activity coefficient

9-25

activity coefficient

γ_{B}

1

·one

for a solute in a solution, quotient of activity of solute (t9-24), and quotient of the molality (t9-15) of substance and standard molality…

9-26standard absolute activity <in a solution>

9-26

standard absolute activity

λ_{B}^{& # 8854;}

1

·one

for a solute in a solution: where denotes summation over all solutes, is a standard pressure (iso80000-4), is standard molality, and is the…

9-27activity of solvent, relative activity of solvent

9-27.1

activity of solvent, relative activity of solvent

a_{A}

1

·one

for the solvent in a solution, quotient of the absolute activity of substance , (t9-18), and that, , of the pure solvent at the same…

9-27.2

osmotic factor of solvent, osmotic coefficient of solvent A

φ

1

·one

quantity given by: where is the molar mass (t9-4) of the solvent , denotes summation over all the solutes, is the molality of solute…

9-27.3

standard absolute activity of solvent

λ_{A}^{& # 8854;}

1

·one

for solvent , standard absolute activity (t9-23) of the pure substance at the same temperature (iso80000-5) and at a standard pressure…

9-28osmotic pressure

9-28

osmotic pressure

Π

P a

k g \cdot m^{- 1} \cdot s^{- 2}

·pascal, kilogram per metre second squared

excess pressure (iso80000-4) required to maintain osmotic equilibrium between a solution and the pure solvent separated by a membrane…

9-29stoichiometric number of substance

9-29

stoichiometric number of substance

ν_{B}

1

·one

for substance , an integer number or a simple fraction, being negative for a reactant and positive for a product, occurring in the…

9-30affinity of a chemical reaction

9-30

affinity of a chemical reaction

A

\frac{J}{m} o l

k g \cdot m^{2} \cdot s^{- 2} \cdot m o l^{- 1}

·joule per mole, kilogram square metre per second squared mole

negative of the sum over all substances of products of stoichiometric number of substance (t9-29) and chemical potential of substance…

9-31extent of reaction

9-31

extent of reaction

ξ

m o l

·mole

difference of initial amount of substance (t9-2) and equilibrium amount of substance (t9-2) divided by stoichiometric number of substance…

9-32standard equilibrium constant, thermodynamic equilibrium constant

9-32

standard equilibrium constant, thermodynamic equilibrium constant

K^{& # 8854;}

1

·one

for a chemical reaction, product for all substances of standard absolute activity of substance (t9-26) in power of minus stoichiometric…

9-33equilibrium constant <pressure basis>

9-33

equilibrium constant

K_{p}

{unitsml(Pa)}^{\sum ν_{B}}

{(unitsml(kg*m^(-1)*s^(-2)))}^{\sum ν_{B}}

·pascal to the power of sum of stoichiometric numbers, kilogram metre per second squared to the power of sum of stoichiometric numbers

for gases, product for all substances of partial pressure of substance (t9-19) in power of its stoichiometric number (t9-29):

9-34equilibrium constant <concentration basis>

9-34

equilibrium constant

K_{c}

{(unitsml(mol/m^3))}^{\sum ν_{B}}

·mole per cubic metre to the power of sum of stoichiometric numbers

for solutions, product for all substances of concentration of substance (t9-9.1) in power of its stoichiometric number (t9-29):

9-35microcanonical partition function

9-35.1

microcanonical partition function

Ω

1

·one

number of all quantum states consistent with given energy (iso80000-4), volume (iso80000-3), and external fields:

9-35.2

canonical partition function

Z

1

·one

sum over quantum states of energy (iso80000-4), expressed by: where is the Boltzmann constant (iso80000-1), and is thermodynamic…

9-35.3

grand-canonical partition function, grand partition function

Ξ

1

·one

sum of canonical partition function for the given number of particles multiplied by absolute activities (t9-18) of particles :

9-35.4

molecular partition function, partition function of a molecule

q

1

·one

quantity given by: where is the energy (iso80000-5) of the -th level of the molecule consistent with given volume (iso80000-3) and external…

9-36statistical weight of subsystem

9-36.1

statistical weight of subsystem

g

1

·one

number of different microstates in a subsystem

9-36.2

degeneracy, multiplicity

g

1

·one

for quantum level, statistical weight of that level

9-37molar gas constant

9-37.1

molar gas constant

R

\frac{J}{m o l \cdot K}

k g \cdot m^{2} \cdot s^{- 2} \cdot K^{- 1} \cdot m o l^{- 1}

·joule per mole kelvin, kilogram square metre per second squared kelvin mole

product of the Boltzmann constant (iso80000-1) and the Avogadro constant (iso80000-1)

9-37.2

specific gas constant

R_{s}

\frac{J}{k g \cdot K}

m^{2} \cdot s^{- 2} \cdot K^{- 1}

·joule per kilogram kelvin, square metre per second squared kelvin

quotient of molar gas constant (t9-37.1) and molar mass (t9-4) , i.e.

9-38mean free path <chemistry>

9-38

mean free path

l

λ

m

·metre

for a particle, the average distance (iso80000-3) between two successive collisions with other particles

9-39diffusion coefficient <chemistry>

9-39

diffusion coefficient

D

m^{2} \cdot s^{- 1}

·square metre per second

proportionality coefficient of local molecular concentration (t9-9.2) of substance in the mixture multiplied by the local average velocity…

9-40thermal diffusion ratio

9-40.1

thermal diffusion ratio

k_{T}

1

·one

in a steady-state of a binary mixture in which thermal diffusion occurs, proportionality factor between gradient of the amount-of-substance…

9-40.2

thermal diffusion factor

α_{T}

1

m^{2} \cdot s^{- 1}

·one, square metre per second

quotient of the thermal diffusion ratio (t9-40.1), and the product of the local amount-of-substance fractions , (t9-13) of two substances…

9-41thermal diffusion coefficient

9-41

thermal diffusion coefficient

D_{T}

m^{2} \cdot s^{- 1}

·square metre per second

product of the thermal diffusion ratio (t9-40.1) and the diffusion coefficient (t9-39):

9-42ionic strength

9-42

ionic strength

I

m o l \cdot k g^{- 1}

·mole per kilogram

in a sample, one half of the sum of square of the charge number (iso80000-10) of -th ion multiplied by its molality (t9-15) over any…

9-43degree of dissociation, dissociation fraction

9-43

degree of dissociation, dissociation fraction

α

1

·one

in a sample, quotient of the number of dissociated molecules and the total number of molecules:

9-44electrolytic conductivity

9-44

electrolytic conductivity

κ

\frac{S}{m}

k g^{- 1} \cdot m^{- 3} \cdot s^{3} \cdot A^{2}

·siemens per metre, second cubed ampere squared per kilogram cubic metre

quotient of the magnitude of electric current density (iec80000-6) and the magnitude electric field strength (iec80000-6) in an electrolyte:

9-45molar conductivity

9-45

molar conductivity

Λ_{m}

S \cdot \frac{m^{2}}{m} o l

k g^{- 1} \cdot s^{3} \cdot A^{2} \cdot m o l^{- 1}

·siemens square metre per mole, second cubed ampere squared per kilogram mole

in an electrolyte, quotient of electrolytic conductivity (t9-44) and amount-of-substance concentration (t9-12.1):

9-46transport number of the ion stem:["B"], current fraction of the ion stem:["B"]

9-46

transport number of the ion B, current fraction of the ion B

t_{B}

1

·one

for the ion , quotient of electric current (iec80000-6) carried by the ion and total electric current (iec80000-6) in an electrolyte:

9-47angle of optical rotation

9-47

angle of optical rotation

α

r a d

·radian

angle through which plane-polarized light is rotated clockwise, as seen when facing the light source, in passing through an optically…

9-48molar optical rotatory power

9-48

molar optical rotatory power

α_{n}

r a d \cdot \frac{m^{2}}{m} o l

m^{2} \cdot m o l^{- 1}

·radian square metre per mole, square metre per mole

angle of optical rotation (t9-47), multiplied by the quotient of cross-sectional area (iso80000-3) of a linearly polarized light beam and…

9-49specific optical rotatory power

9-49

specific optical rotatory power

α_{m}

r a d \cdot \frac{m^{2}}{k} g^{1}

k g^{- 1} \cdot m^{2}

·radian square metre per kilogram, square metre per kilogram

angle of optical rotation (t9-47), multiplied by the quotient of cross-sectional area (iso80000-3) of a linearly polarized light beam and…

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