Legacy Chemicals (thermo.chemical)¶

class thermo.chemical.Chemical(ID, T=298.15, P=101325, autocalc=True)[source]¶

Bases: object

Creates a Chemical object which contains basic information such as molecular weight and the structure of the species, as well as thermodynamic and transport properties as a function of temperature and pressure.

Parameters

IDstr

One of the following [-]:

Name, in IUPAC form or common form or a synonym registered in PubChem
InChI name, prefixed by ‘InChI=1S/’ or ‘InChI=1/’
InChI key, prefixed by ‘InChIKey=’
PubChem CID, prefixed by ‘PubChem=’
SMILES (prefix with ‘SMILES=’ to ensure smiles parsing)
CAS number

Tfloat, optional

Temperature of the chemical (default 298.15 K), [K]

Pfloat, optional

Pressure of the chemical (default 101325 Pa) [Pa]

Notes

Warning

The Chemical class is not designed for high-performance or the ability to use different thermodynamic models. It is especially limited in its multiphase support and the ability to solve with specifications other than temperature and pressure. It is impossible to change constant properties such as a compound’s critical temperature in this interface.

It is recommended to switch over to the thermo.flash interface which solves those problems and is better positioned to grow. That interface also requires users to be responsible for their chemical constants and pure component correlations; while default values can easily be loaded for most compounds, the user is ultimately responsible for them.

Examples

Creating chemical objects:

>>> Chemical('hexane')
<Chemical [hexane], T=298.15 K, P=101325 Pa>

>>> Chemical('CCCCCCCC', T=500, P=1E7)
<Chemical [octane], T=500.00 K, P=10000000 Pa>

>>> Chemical('7440-36-0', P=1000)
<Chemical [antimony], T=298.15 K, P=1000 Pa>

Getting basic properties:

>>> N2 = Chemical('Nitrogen')
>>> N2.Tm, N2.Tb, N2.Tc # melting, boiling, and critical points [K]
(63.15, 77.355, 126.2)
>>> N2.Pt, N2.Pc # sublimation and critical pressure [Pa]
(12526.9697368421, 3394387.5)
>>> N2.CAS, N2.formula, N2.InChI, N2.smiles, N2.atoms # CAS number, formula, InChI string, smiles string, dictionary of atomic elements and their count
('7727-37-9', 'N2', 'N2/c1-2', 'N#N', {'N': 2})

Changing the T/P of the chemical, and gettign temperature-dependent properties:

>>> N2.Cp, N2.rho, N2.mu # Heat capacity [J/kg/K], density [kg/m^3], viscosity [Pa*s]
(1039.4978324480921, 1.1452416223829405, 1.7804740647270688e-05)
>>> N2.calculate(T=65, P=1E6) # set it to a liquid at 65 K and 1 MPa
>>> N2.phase
'l'
>>> N2.Cp, N2.rho, N2.mu # properties are now of the liquid phase
(2002.8819854804037, 861.3539919443364, 0.0002857739143670701)

Molar units are also available for properties:

>>> N2.Cpm, N2.Vm, N2.Hvapm # heat capacity [J/mol/K], molar volume [m^3/mol], enthalpy of vaporization [J/mol]
(56.10753421205674, 3.252251717875631e-05, 5982.710998291719)

A great deal of properties are available; for a complete list look at the attributes list.

>>> N2.alpha, N2.JT # thermal diffusivity [m^2/s], Joule-Thompson coefficient [K/Pa]
(9.874883993253272e-08, -4.0009932695519242e-07)

>>> N2.isentropic_exponent, N2.isobaric_expansion
(1.4000000000000001, 0.0047654228408661571)

For pure species, the phase is easily identified, allowing for properties to be obtained without needing to specify the phase. However, the properties are also available in the hypothetical gas phase (when under the boiling point) and in the hypothetical liquid phase (when above the boiling point) as these properties are needed to evaluate mixture properties. Specify the phase of a property to be retrieved by appending ‘l’ or ‘g’ or ‘s’ to the property.

>>> tol = Chemical('toluene')

>>> tol.rhog, tol.Cpg, tol.kg, tol.mug
(4.241646701894199, 1126.5533755283168, 0.00941385692301755, 6.973325939594919e-06)

Temperature dependent properties are calculated by objects which provide many useful features related to the properties. To determine the temperature at which nitrogen has a saturation pressure of 1 MPa:

>>> N2.VaporPressure.solve_property(1E6)
103.73528598652341

To compute an integral of the ideal-gas heat capacity of nitrogen to determine the enthalpy required for a given change in temperature. Note the thermodynamic objects calculate values in molar units always.

>>> N2.HeatCapacityGas.T_dependent_property_integral(100, 120) # J/mol/K
582.0121860897898

Derivatives of properties can be calculated as well, as may be needed by for example heat transfer calculations:

>>> N2.SurfaceTension.T_dependent_property_derivative(77)
-0.00022695346296730534

If a property is needed at multiple temperatures or pressures, it is faster to use the object directly to perform the calculation rather than setting the conditions for the chemical.

>>> [N2.VaporPressure(T) for T in range(80, 120, 10)]
[136979.4840843189, 360712.5746603142, 778846.276691705, 1466996.7208525643]

These objects are also how the methods by which the properties are calculated can be changed. To see the available methods for a property:

>>> N2.VaporPressure.all_methods
set(['VDI_PPDS', 'BOILING_CRITICAL', 'WAGNER_MCGARRY', 'AMBROSE_WALTON', 'COOLPROP', 'LEE_KESLER_PSAT', 'EOS', 'ANTOINE_POLING', 'SANJARI', 'DIPPR_PERRY_8E', 'Edalat', 'WAGNER_POLING'])

To specify the method which should be used for calculations of a property. In the example below, the Lee-kesler correlation for vapor pressure is specified.

>>> N2.calculate(80)
>>> N2.Psat
136979.4840843189
>>> N2.VaporPressure.method = 'LEE_KESLER_PSAT'
>>> N2.Psat
134987.76815364443

For memory reduction, these objects are shared by all chemicals which are the same; new instances will use the same specified methods.

>>> N2_2 = Chemical('nitrogen')
>>> N2_2.VaporPressure.user_methods
['LEE_KESLER_PSAT']

To disable this behavior, set thermo.chemical.caching to False.

>>> import thermo
>>> thermo.chemical.caching = False
>>> N2_3 = Chemical('nitrogen')
>>> N2_3.VaporPressure.user_methods
[]

Properties may also be plotted via these objects:

>>> N2.VaporPressure.plot_T_dependent_property() 
>>> N2.VolumeLiquid.plot_isotherm(T=77, Pmin=1E5, Pmax=1E7) 
>>> N2.VolumeLiquid.plot_isobar(P=1E6,  Tmin=66, Tmax=120) 
>>> N2.VolumeLiquid.plot_TP_dependent_property(Tmin=60, Tmax=100,  Pmin=1E5, Pmax=1E7) 

Attributes

Tfloat: Temperature of the chemical, [K]
Pfloat: Pressure of the chemical, [Pa]
phasestr: Phase of the chemical; one of ‘s’, ‘l’, ‘g’, or ‘l/g’.
IDstr: User specified string by which the chemical’s CAS was looked up.
CASstr: The CAS number of the chemical.
PubChemint: PubChem Compound identifier (CID) of the chemical; all chemicals are sourced from their database. Chemicals can be looked at online at https://pubchem.ncbi.nlm.nih.gov.
MWfloat: Molecular weight of the compound, [g/mol]
formulastr: Molecular formula of the compound.
atomsdict: dictionary of counts of individual atoms, indexed by symbol with proper capitalization, [-]
similarity_variablefloat: Similarity variable, see chemicals.elements.similarity_variable for the definition, [mol/g]
smilesstr: Simplified molecular-input line-entry system representation of the compound.
InChIstr: IUPAC International Chemical Identifier of the compound.
InChI_Keystr: 25-character hash of the compound’s InChI.
IUPAC_namestr: Preferred IUPAC name for a compound.
synonymslist of strings: All synonyms for the compound found in PubChem, sorted by popularity.
Tmfloat: Melting temperature [K]
Tbfloat: Boiling temperature [K]
Tcfloat: Critical temperature [K]
Pcfloat: Critical pressure [Pa]
Vcfloat: Critical volume [m^3/mol]
Zcfloat: Critical compressibility [-]
rhocfloat: Critical density [kg/m^3]
rhocmfloat: Critical molar density [mol/m^3]
omegafloat: Acentric factor [-]
StielPolarfloat: Stiel Polar factor, see chemicals.acentric.Stiel_polar_factor for the definition [-]
Ttfloat: Triple temperature, [K]
Ptfloat: Triple pressure, [Pa]
Hfusfloat: Enthalpy of fusion [J/kg]
Hfusmfloat: Molar enthalpy of fusion [J/mol]
Hsubfloat: Enthalpy of sublimation [J/kg]
Hsubmfloat: Molar enthalpy of sublimation [J/mol]
Hfmfloat: Standard state molar enthalpy of formation, [J/mol]
Hffloat: Standard enthalpy of formation in a mass basis, [J/kg]
Hfgmfloat: Ideal-gas molar enthalpy of formation, [J/mol]
Hfgfloat: Ideal-gas enthalpy of formation in a mass basis, [J/kg]
Hcmfloat: Molar higher heat of combustion [J/mol]
Hcfloat: Higher Heat of combustion [J/kg]
Hcm_lowerfloat: Molar lower heat of combustion [J/mol]
Hc_lowerfloat: Lower Heat of combustion [J/kg]
S0mfloat: Standard state absolute molar entropy of the chemical, [J/mol/K]
S0float: Standard state absolute entropy of the chemical, [J/kg/K]
S0gmfloat: Absolute molar entropy in an ideal gas state of the chemical, [J/mol/K]
S0gfloat: Absolute mass entropy in an ideal gas state of the chemical, [J/kg/K]
Gfmfloat: Standard state molar change of Gibbs energy of formation [J/mol]
Gffloat: Standard state change of Gibbs energy of formation [J/kg]
Gfgmfloat: Ideal-gas molar change of Gibbs energy of formation [J/mol]
Gfgfloat: Ideal-gas change of Gibbs energy of formation [J/kg]
Sfmfloat: Standard state molar change of entropy of formation, [J/mol/K]
Sffloat: Standard state change of entropy of formation, [J/kg/K]
Sfgmfloat: Ideal-gas molar change of entropy of formation, [J/mol/K]
Sfgfloat: Ideal-gas change of entropy of formation, [J/kg/K]
Hcgmfloat: Higher molar heat of combustion of the chemical in the ideal gas state, [J/mol]
Hcgfloat: Higher heat of combustion of the chemical in the ideal gas state, [J/kg]
Hcgm_lowerfloat: Lower molar heat of combustion of the chemical in the ideal gas state, [J/mol]
Hcg_lowerfloat: Lower heat of combustion of the chemical in the ideal gas state, [J/kg]
Tflashfloat: Flash point of the chemical, [K]
Tautoignitionfloat: Autoignition point of the chemical, [K]
LFLfloat: Lower flammability limit of the gas in an atmosphere at STP, mole fraction [-]
UFLfloat: Upper flammability limit of the gas in an atmosphere at STP, mole fraction [-]
TWAtuple[quantity, unit]: Time-Weighted Average limit on worker exposure to dangerous chemicals.
STELtuple[quantity, unit]: Short-term Exposure limit on worker exposure to dangerous chemicals.
Ceilingtuple[quantity, unit]: Ceiling limits on worker exposure to dangerous chemicals.
Skinbool: Whether or not a chemical can be absorbed through the skin.
Carcinogenstr or dict: Carcinogen status information.
dipolefloat: Dipole moment in debye, [3.33564095198e-30 ampere*second^2]
Stockmayerfloat: Lennard-Jones depth of potential-energy minimum over k, [K]
molecular_diameterfloat: Lennard-Jones molecular diameter, [angstrom]
GWPfloat: Global warming potential (default 100-year outlook) (impact/mass chemical)/(impact/mass CO2), [-]
ODPfloat: Ozone Depletion potential (impact/mass chemical)/(impact/mass CFC-11), [-]
logPfloat: Octanol-water partition coefficient, [-]
legal_statusstr or dict: Dictionary of legal status indicators for the chemical.
economic_statuslist: Dictionary of economic status indicators for the chemical.
RIfloat: Refractive Index on the Na D line, [-]
RITfloat: Temperature at which refractive index reading was made
conductivityfloat: Electrical conductivity of the fluid, [S/m]
conductivityTfloat: Temperature at which conductivity measurement was made
VaporPressureobject: Instance of thermo.vapor_pressure.VaporPressure, with data and methods loaded for the chemical; performs the actual calculations of vapor pressure of the chemical.
EnthalpyVaporizationobject: Instance of thermo.phase_change.EnthalpyVaporization, with data and methods loaded for the chemical; performs the actual calculations of molar enthalpy of vaporization of the chemical.
VolumeSolidobject: Instance of thermo.volume.VolumeSolid, with data and methods loaded for the chemical; performs the actual calculations of molar volume of the solid phase of the chemical.
VolumeLiquidobject: Instance of thermo.volume.VolumeLiquid, with data and methods loaded for the chemical; performs the actual calculations of molar volume of the liquid phase of the chemical.
VolumeGasobject: Instance of thermo.volume.VolumeGas, with data and methods loaded for the chemical; performs the actual calculations of molar volume of the gas phase of the chemical.
HeatCapacitySolidobject: Instance of thermo.heat_capacity.HeatCapacitySolid, with data and methods loaded for the chemical; performs the actual calculations of molar heat capacity of the solid phase of the chemical.
HeatCapacityLiquidobject: Instance of thermo.heat_capacity.HeatCapacityLiquid, with data and methods loaded for the chemical; performs the actual calculations of molar heat capacity of the liquid phase of the chemical.
HeatCapacityGasobject: Instance of thermo.heat_capacity.HeatCapacityGas, with data and methods loaded for the chemical; performs the actual calculations of molar heat capacity of the gas phase of the chemical.
ViscosityLiquidobject: Instance of thermo.viscosity.ViscosityLiquid, with data and methods loaded for the chemical; performs the actual calculations of viscosity of the liquid phase of the chemical.
ViscosityGasobject: Instance of thermo.viscosity.ViscosityGas, with data and methods loaded for the chemical; performs the actual calculations of viscosity of the gas phase of the chemical.
ThermalConductivityLiquidobject: Instance of thermo.thermal_conductivity.ThermalConductivityLiquid, with data and methods loaded for the chemical; performs the actual calculations of thermal conductivity of the liquid phase of the chemical.
ThermalConductivityGasobject: Instance of thermo.thermal_conductivity.ThermalConductivityGas, with data and methods loaded for the chemical; performs the actual calculations of thermal conductivity of the gas phase of the chemical.
SurfaceTensionobject: Instance of thermo.interface.SurfaceTension, with data and methods loaded for the chemical; performs the actual calculations of surface tension of the chemical.
Permittivityobject: Instance of thermo.permittivity.PermittivityLiquid, with data and methods loaded for the chemical; performs the actual calculations of permittivity of the chemical.
Psat_298float: Vapor pressure of the chemical at 298.15 K, [Pa]
phase_STPstr: Phase of the chemical at 298.15 K and 101325 Pa; one of ‘s’, ‘l’, ‘g’, or ‘l/g’.
Vml_Tbfloat: Molar volume of liquid phase at the normal boiling point [m^3/mol]
Vml_Tmfloat: Molar volume of liquid phase at the melting point [m^3/mol]
Vml_STPfloat: Molar volume of liquid phase at 298.15 K and 101325 Pa [m^3/mol]
rhoml_STPfloat: Molar density of liquid phase at 298.15 K and 101325 Pa [mol/m^3]
Vmg_STPfloat: Molar volume of gas phase at 298.15 K and 101325 Pa according to the ideal gas law, [m^3/mol]
Vms_Tmfloat: Molar volume of solid phase at the melting point [m^3/mol]
rhos_Tmfloat: Mass density of solid phase at the melting point [kg/m^3]
Hvap_Tbmfloat: Molar enthalpy of vaporization at the normal boiling point [J/mol]
Hvap_Tbfloat: Mass enthalpy of vaporization at the normal boiling point [J/kg]
Hvapm_298float: Molar enthalpy of vaporization at 298.15 K [J/mol]
Hvap_298float: Mass enthalpy of vaporization at 298.15 K [J/kg]
alpha: Thermal diffusivity of the chemical at its current temperature, pressure, and phase in units of [m^2/s].
alphag: Thermal diffusivity of the gas phase of the chemical at its current temperature and pressure, in units of [m^2/s].
alphal: Thermal diffusivity of the liquid phase of the chemical at its current temperature and pressure, in units of [m^2/s].
API: API gravity of the liquid phase of the chemical, [degrees].
aromatic_rings: Number of aromatic rings in a chemical, computed with RDKit from a chemical’s SMILES.
atom_fractions: Dictionary of atom:fractional occurence of the elements in a chemical.
Bvirial: Second virial coefficient of the gas phase of the chemical at its current temperature and pressure, in units of [mol/m^3].
charge: Charge of a chemical, computed with RDKit from a chemical’s SMILES.
Cp: Mass heat capacity of the chemical at its current phase and temperature, in units of [J/kg/K].
Cpg: Gas-phase heat capacity of the chemical at its current temperature, in units of [J/kg/K].
Cpgm: Gas-phase ideal gas heat capacity of the chemical at its current temperature, in units of [J/mol/K].
Cpl: Liquid-phase heat capacity of the chemical at its current temperature, in units of [J/kg/K].
Cplm: Liquid-phase heat capacity of the chemical at its current temperature, in units of [J/mol/K].
Cpm: Molar heat capacity of the chemical at its current phase and temperature, in units of [J/mol/K].
Cps: Solid-phase heat capacity of the chemical at its current temperature, in units of [J/kg/K].
Cpsm: Solid-phase heat capacity of the chemical at its current temperature, in units of [J/mol/K].
Cvg: Gas-phase ideal-gas contant-volume heat capacity of the chemical at its current temperature, in units of [J/kg/K].
Cvgm: Gas-phase ideal-gas contant-volume heat capacity of the chemical at its current temperature, in units of [J/mol/K].
eos: Equation of state object held by the chemical; used to calculate excess thermodynamic quantities, and also provides a vapor pressure curve, enthalpy of vaporization curve, fugacity, thermodynamic partial derivatives, and more; see thermo.eos for a full listing.
Hill: Hill formula of a compound.
Hvap: Enthalpy of vaporization of the chemical at its current temperature, in units of [J/kg].
Hvapm: Enthalpy of vaporization of the chemical at its current temperature, in units of [J/mol].
isentropic_exponent: Gas-phase ideal-gas isentropic exponent of the chemical at its current temperature, [dimensionless].
isobaric_expansion: Isobaric (constant-pressure) expansion of the chemical at its current phase and temperature, in units of [1/K].
isobaric_expansion_g: Isobaric (constant-pressure) expansion of the gas phase of the chemical at its current temperature and pressure, in units of [1/K].
isobaric_expansion_l: Isobaric (constant-pressure) expansion of the liquid phase of the chemical at its current temperature and pressure, in units of [1/K].
JT: Joule Thomson coefficient of the chemical at its current phase and temperature, in units of [K/Pa].
JTg: Joule Thomson coefficient of the chemical in the gas phase at its current temperature and pressure, in units of [K/Pa].
JTl: Joule Thomson coefficient of the chemical in the liquid phase at its current temperature and pressure, in units of [K/Pa].
k: Thermal conductivity of the chemical at its current phase, temperature, and pressure in units of [W/m/K].
kg: Thermal conductivity of the chemical in the gas phase at its current temperature and pressure, in units of [W/m/K].
kl: Thermal conductivity of the chemical in the liquid phase at its current temperature and pressure, in units of [W/m/K].
mass_fractions: Dictionary of atom:mass-weighted fractional occurence of elements.
mu: Viscosity of the chemical at its current phase, temperature, and pressure in units of [Pa*s].
mug: Viscosity of the chemical in the gas phase at its current temperature and pressure, in units of [Pa*s].
mul: Viscosity of the chemical in the liquid phase at its current temperature and pressure, in units of [Pa*s].
nu: Kinematic viscosity of the the chemical at its current temperature, pressure, and phase in units of [m^2/s].
nug: Kinematic viscosity of the gas phase of the chemical at its current temperature and pressure, in units of [m^2/s].
nul: Kinematic viscosity of the liquid phase of the chemical at its current temperature and pressure, in units of [m^2/s].
Parachor: Parachor of the chemical at its current temperature and pressure, in units of [N^0.25*m^2.75/mol].
permittivity: Relative permittivity (dielectric constant) of the chemical at its current temperature, [dimensionless].
Poynting: Poynting correction factor [dimensionless] for use in phase equilibria methods based on activity coefficients or other reference states.
Pr: Prandtl number of the chemical at its current temperature, pressure, and phase; [dimensionless].
Prg: Prandtl number of the gas phase of the chemical at its current temperature and pressure, [dimensionless].
Prl: Prandtl number of the liquid phase of the chemical at its current temperature and pressure, [dimensionless].
Psat: Vapor pressure of the chemical at its current temperature, in units of [Pa].
PSRK_groups: Dictionary of PSRK subgroup: count groups for the PSRK subgroups, as determined by DDBST’s online service.
rdkitmol: RDKit object of the chemical, without hydrogen.
rdkitmol_Hs: RDKit object of the chemical, with hydrogen.
rho: Mass density of the chemical at its current phase and temperature and pressure, in units of [kg/m^3].
rhog: Gas-phase mass density of the chemical at its current temperature and pressure, in units of [kg/m^3].
rhogm: Molar density of the chemical in the gas phase at the current temperature and pressure, in units of [mol/m^3].
rhol: Liquid-phase mass density of the chemical at its current temperature and pressure, in units of [kg/m^3].
rholm: Molar density of the chemical in the liquid phase at the current temperature and pressure, in units of [mol/m^3].
rhom: Molar density of the chemical at its current phase and temperature and pressure, in units of [mol/m^3].
rhos: Solid-phase mass density of the chemical at its current temperature, in units of [kg/m^3].
rhosm: Molar density of the chemical in the solid phase at the current temperature and pressure, in units of [mol/m^3].
rings: Number of rings in a chemical, computed with RDKit from a chemical’s SMILES.
SG: Specific gravity of the chemical, [dimensionless].
SGg: Specific gravity of the gas phase of the chemical, [dimensionless].
SGl: Specific gravity of the liquid phase of the chemical at the specified temperature and pressure, [dimensionless].
SGs: Specific gravity of the solid phase of the chemical at the specified temperature and pressure, [dimensionless].
sigma: Surface tension of the chemical at its current temperature, in units of [N/m].
solubility_parameter: Solubility parameter of the chemical at its current temperature and pressure, in units of [Pa^0.5].
UNIFAC_Dortmund_groups: Dictionary of Dortmund UNIFAC subgroup: count groups for the Dortmund UNIFAC subgroups, as determined by DDBST’s online service.
UNIFAC_groups: Dictionary of UNIFAC subgroup: count groups for the original UNIFAC subgroups, as determined by DDBST’s online service.
UNIFAC_R: UNIFAC R (normalized Van der Waals volume), dimensionless.
UNIFAC_Q: UNIFAC Q (normalized Van der Waals area), dimensionless.
Van_der_Waals_area: Unnormalized Van der Waals area, in units of [m^2/mol].
Van_der_Waals_volume: Unnormalized Van der Waals volume, in units of [m^3/mol].
Vm: Molar volume of the chemical at its current phase and temperature and pressure, in units of [m^3/mol].
Vmg: Gas-phase molar volume of the chemical at its current temperature and pressure, in units of [m^3/mol].
Vml: Liquid-phase molar volume of the chemical at its current temperature and pressure, in units of [m^3/mol].
Vms: Solid-phase molar volume of the chemical at its current temperature, in units of [m^3/mol].
Z: Compressibility factor of the chemical at its current phase and temperature and pressure, [dimensionless].
Zg: Compressibility factor of the chemical in the gas phase at the current temperature and pressure, [dimensionless].
Zl: Compressibility factor of the chemical in the liquid phase at the current temperature and pressure, [dimensionless].
Zs: Compressibility factor of the chemical in the solid phase at the current temperature and pressure, [dimensionless].

Methods

`Reynolds`([V, D])
`draw_2d`([width, height, Hs])	Interface for drawing a 2D image of the molecule.
`draw_3d`([width, height, style, Hs, atom_labels])	Interface for drawing an interactive 3D view of the molecule.

Bond
Capillary
Grashof
Jakob
Peclet_heat
Tsat
Weber
calc_H
calc_H_excess
calc_S
calc_S_excess
calculate
calculate_PH
calculate_PS
calculate_TH
calculate_TS
set_TP_sources
set_constant_sources
set_constants
set_eos
set_ref
set_thermo

property A¶

Helmholtz energy of the chemical at its current temperature and pressure, in units of [J/kg].

This property requires that thermo.chemical.set_thermo ran successfully to be accurate. It also depends on the molar volume of the chemical at its current conditions.

property API¶

API gravity of the liquid phase of the chemical, [degrees]. The reference condition is water at 15.6 °C (60 °F) and 1 atm (rho=999.016 kg/m^3, standardized).

Examples

>>> Chemical('water').API
9.999752435378895

property Am¶

Helmholtz energy of the chemical at its current temperature and pressure, in units of [J/mol].

This property requires that thermo.chemical.set_thermo ran successfully to be accurate. It also depends on the molar volume of the chemical at its current conditions.

Bond(L=None)[source]¶

property Bvirial¶

Second virial coefficient of the gas phase of the chemical at its current temperature and pressure, in units of [mol/m^3].

This property uses the object-oriented interface thermo.volume.VolumeGas, converting its result with thermo.utils.B_from_Z.

Examples

>>> Chemical('water').Bvirial
-0.0009596286322838357

Capillary(V=None)[source]¶

property Cp¶

Mass heat capacity of the chemical at its current phase and temperature, in units of [J/kg/K].

Utilizes the object oriented interfaces thermo.heat_capacity.HeatCapacitySolid, thermo.heat_capacity.HeatCapacityLiquid, and thermo.heat_capacity.HeatCapacityGas to perform the actual calculation of each property. Note that those interfaces provide output in molar units (J/mol/K).

Examples

>>> w = Chemical('water')
>>> w.Cp, w.phase
(4180.597021827336, 'l')
>>> Chemical('palladium').Cp
234.26767209171211

property Cpg¶

Gas-phase heat capacity of the chemical at its current temperature, in units of [J/kg/K]. For calculation of this property at other temperatures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.heat_capacity.HeatCapacityGas; each Chemical instance creates one to actually perform the calculations. Note that that interface provides output in molar units.

Examples

>>> w = Chemical('water', T=520)
>>> w.Cpg
1967.6698314620658

property Cpgm¶

Gas-phase ideal gas heat capacity of the chemical at its current temperature, in units of [J/mol/K]. For calculation of this property at other temperatures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.heat_capacity.HeatCapacityGas; each Chemical instance creates one to actually perform the calculations.

Examples

>>> Chemical('water').Cpgm
33.583577868850675
>>> Chemical('water').HeatCapacityGas.T_dependent_property(320)
33.67865044005934
>>> Chemical('water').HeatCapacityGas.T_dependent_property_integral(300, 320)
672.6480417835064

property Cpl¶

Liquid-phase heat capacity of the chemical at its current temperature, in units of [J/kg/K]. For calculation of this property at other temperatures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.heat_capacity.HeatCapacityLiquid; each Chemical instance creates one to actually perform the calculations. Note that that interface provides output in molar units.

Examples

>>> Chemical('water', T=320).Cpl
4177.518996988284

Ideal entropy change of water from 280 K to 340 K, output converted back to mass-based units of J/kg/K.

>>> dSm = Chemical('water').HeatCapacityLiquid.T_dependent_property_integral_over_T(280, 340)
>>> property_molar_to_mass(dSm, Chemical('water').MW)
812.1024585274956

property Cplm¶

Liquid-phase heat capacity of the chemical at its current temperature, in units of [J/mol/K]. For calculation of this property at other temperatures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.heat_capacity.HeatCapacityLiquid; each Chemical instance creates one to actually perform the calculations.

Notes

Some methods give heat capacity along the saturation line, some at 1 atm but only up to the normal boiling point, and some give heat capacity at 1 atm up to the normal boiling point and then along the saturation line. Real-liquid heat capacity is pressure dependent, but this interface is not.

Examples

>>> Chemical('water').Cplm
75.31462591538556
>>> Chemical('water').HeatCapacityLiquid.T_dependent_property(320)
75.2591744360631
>>> Chemical('water').HeatCapacityLiquid.T_dependent_property_integral(300, 320)
1505.0619005000553

property Cpm¶

Molar heat capacity of the chemical at its current phase and temperature, in units of [J/mol/K].

Utilizes the object oriented interfaces thermo.heat_capacity.HeatCapacitySolid, thermo.heat_capacity.HeatCapacityLiquid, and thermo.heat_capacity.HeatCapacityGas to perform the actual calculation of each property.

Examples

>>> Chemical('cubane').Cpm
137.05489206785944
>>> Chemical('ethylbenzene', T=550, P=3E6).Cpm
294.18449553310046

property Cps¶

Solid-phase heat capacity of the chemical at its current temperature, in units of [J/kg/K]. For calculation of this property at other temperatures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.heat_capacity.HeatCapacitySolid; each Chemical instance creates one to actually perform the calculations. Note that that interface provides output in molar units.

Examples

>>> Chemical('palladium', T=400).Cps
241.63563239992484
>>> Pd = Chemical('palladium', T=400)
>>> Cpsms = [Pd.HeatCapacitySolid.T_dependent_property(T) for T in np.linspace(300,500, 5)]
>>> [property_molar_to_mass(Cps, Pd.MW) for Cps in Cpsms]
[234.40150347679008, 238.01856793835751, 241.63563239992484, 245.25269686149224, 248.86976132305958]

property Cpsm¶

Solid-phase heat capacity of the chemical at its current temperature, in units of [J/mol/K]. For calculation of this property at other temperatures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.heat_capacity.HeatCapacitySolid; each Chemical instance creates one to actually perform the calculations.

Examples

>>> Chemical('palladium').Cpsm
24.930765664000003
>>> Chemical('palladium').HeatCapacitySolid.T_dependent_property(320)
25.098979200000002
>>> Chemical('palladium').HeatCapacitySolid.all_methods
set(["PERRY151", 'CRCSTD', 'LASTOVKA_S'])

property Cvg¶

Gas-phase ideal-gas contant-volume heat capacity of the chemical at its current temperature, in units of [J/kg/K]. Subtracts R from the ideal-gas heat capacity; does not include pressure-compensation from an equation of state.

Examples

>>> w = Chemical('water', T=520)
>>> w.Cvg
1506.1471795798861

property Cvgm¶

Gas-phase ideal-gas contant-volume heat capacity of the chemical at its current temperature, in units of [J/mol/K]. Subtracts R from the ideal-gas heat capacity; does not include pressure-compensation from an equation of state.

Examples

>>> w = Chemical('water', T=520)
>>> w.Cvgm
27.13366316134193

Grashof(Tw=None, L=None)[source]¶

property Hill¶

Hill formula of a compound. For a description of the Hill system, see chemicals.elements.atoms_to_Hill.

Examples

>>> Chemical('furfuryl alcohol').Hill
'C5H6O2'

property Hvap¶

Enthalpy of vaporization of the chemical at its current temperature, in units of [J/kg].

This property uses the object-oriented interface thermo.phase_change.EnthalpyVaporization, but converts its results from molar to mass units.

Examples

>>> Chemical('water', T=320).Hvap
2389540.219347256

property Hvapm¶

Enthalpy of vaporization of the chemical at its current temperature, in units of [J/mol]. For calculation of this property at other temperatures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.phase_change.EnthalpyVaporization; each Chemical instance creates one to actually perform the calculations.

Examples

>>> Chemical('water', T=320).Hvapm
43048.23612280223
>>> Chemical('water').EnthalpyVaporization.T_dependent_property(320)
43048.23612280223
>>> Chemical('water').EnthalpyVaporization.all_methods
set(['VDI_PPDS', 'MORGAN_KOBAYASHI', 'VETERE', 'VELASCO', 'LIU', 'COOLPROP', 'CRC_HVAP_298', 'CLAPEYRON', 'SIVARAMAN_MAGEE_KOBAYASHI', 'ALIBAKHSHI', 'DIPPR_PERRY_8E', 'RIEDEL', 'CHEN', 'PITZER', 'CRC_HVAP_TB'])

property JT¶

Joule Thomson coefficient of the chemical at its current phase and temperature, in units of [K/Pa].

\[\mu_{JT} = \left(\frac{\partial T}{\partial P}\right)_H = \frac{1}{C_p} \left[T \left(\frac{\partial V}{\partial T}\right)_P - V\right] = \frac{V}{C_p}\left(\beta T-1\right) \]

Examples

>>> Chemical('water').JT
-2.2150394958666407e-07

property JTg¶

Joule Thomson coefficient of the chemical in the gas phase at its current temperature and pressure, in units of [K/Pa].

\[\mu_{JT} = \left(\frac{\partial T}{\partial P}\right)_H = \frac{1}{C_p} \left[T \left(\frac{\partial V}{\partial T}\right)_P - V\right] = \frac{V}{C_p}\left(\beta T-1\right) \]

Utilizes the temperature-derivative method of thermo.volume.VolumeGas and the temperature-dependent heat capacity method thermo.heat_capacity.HeatCapacityGas to obtain the properties required for the actual calculation.

Examples

>>> Chemical('dodecane', T=400, P=1000).JTg
5.4089897835384913e-05

property JTl¶

Joule Thomson coefficient of the chemical in the liquid phase at its current temperature and pressure, in units of [K/Pa].

\[\mu_{JT} = \left(\frac{\partial T}{\partial P}\right)_H = \frac{1}{C_p} \left[T \left(\frac{\partial V}{\partial T}\right)_P - V\right] = \frac{V}{C_p}\left(\beta T-1\right) \]

Utilizes the temperature-derivative method of thermo.volume.VolumeLiquid and the temperature-dependent heat capacity method thermo.heat_capacity.HeatCapacityLiquid to obtain the properties required for the actual calculation.

Examples

>>> Chemical('dodecane', T=400).JTl
-3.0827160465192742e-07

Jakob(Tw=None)[source]¶

property PSRK_groups¶

Dictionary of PSRK subgroup: count groups for the PSRK subgroups, as determined by DDBST’s online service.

Examples

>>> Chemical('Cumene').PSRK_groups
{1: 2, 9: 5, 13: 1}

property Parachor¶

Parachor of the chemical at its current temperature and pressure, in units of [N^0.25*m^2.75/mol].

\[P = \frac{\sigma^{0.25} MW}{\rho_L - \rho_V} \]

Calculated based on surface tension, density of the liquid phase, and molecular weight. For uses of this property, see thermo.utils.Parachor.

The gas density is calculated using the ideal-gas law.

Examples

>>> Chemical('octane').Parachor
6.2e-05

Peclet_heat(V=None, D=None)[source]¶

property Poynting¶

Poynting correction factor [dimensionless] for use in phase equilibria methods based on activity coefficients or other reference states. Performs the shortcut calculation assuming molar volume is independent of pressure.

\[\text{Poy} = \exp\left[\frac{V_l (P-P^{sat})}{RT}\right] \]

The full calculation normally returns values very close to the approximate ones. This property is defined in terms of pure components only.

Notes

The full equation shown below can be used as follows:

\[\text{Poy} = \exp\left[\frac{\int_{P_i^{sat}}^P V_i^l dP}{RT}\right] \]

>>> from scipy.integrate import quad
>>> c = Chemical('pentane', T=300, P=1E7)
>>> exp(quad(lambda P : c.VolumeLiquid(c.T, P), c.Psat, c.P)[0]/R/c.T)
1.5821826990975127

Examples

>>> Chemical('pentane', T=300, P=1E7).Poynting
1.5743051250679803

property Pr¶

Prandtl number of the chemical at its current temperature, pressure, and phase; [dimensionless].

\[Pr = \frac{C_p \mu}{k} \]

Examples

>>> Chemical('acetone').Pr
4.183039103542709

property Prg¶

Prandtl number of the gas phase of the chemical at its current temperature and pressure, [dimensionless].

\[Pr = \frac{C_p \mu}{k} \]

Utilizes the temperature and pressure dependent object oriented interfaces thermo.viscosity.ViscosityGas, thermo.thermal_conductivity.ThermalConductivityGas, and thermo.heat_capacity.HeatCapacityGas to calculate the actual properties.

Examples

>>> Chemical('NH3').Prg
0.847263731933008

property Prl¶

Prandtl number of the liquid phase of the chemical at its current temperature and pressure, [dimensionless].

\[Pr = \frac{C_p \mu}{k} \]

Utilizes the temperature and pressure dependent object oriented interfaces thermo.viscosity.ViscosityLiquid, thermo.thermal_conductivity.ThermalConductivityLiquid, and thermo.heat_capacity.HeatCapacityLiquid to calculate the actual properties.

Examples

>>> Chemical('nitrogen', T=70).Prl
2.7828214501488886

property Psat¶

Vapor pressure of the chemical at its current temperature, in units of [Pa]. For calculation of this property at other temperatures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.vapor_pressure.VaporPressure; each Chemical instance creates one to actually perform the calculations.

Examples

>>> Chemical('water', T=320).Psat
10533.614271198725
>>> Chemical('water').VaporPressure.T_dependent_property(320)
10533.614271198725
>>> Chemical('water').VaporPressure.all_methods
set(['VDI_PPDS', 'BOILING_CRITICAL', 'WAGNER_MCGARRY', 'AMBROSE_WALTON', 'COOLPROP', 'LEE_KESLER_PSAT', 'EOS', 'ANTOINE_POLING', 'SANJARI', 'DIPPR_PERRY_8E', 'Edalat'])

property R_specific¶

Specific gas constant, in units of [J/kg/K].

Examples

>>> Chemical('water').R_specific
461.52265188218

Reynolds(V=None, D=None)[source]¶

property SG¶

Specific gravity of the chemical, [dimensionless].

For gas-phase conditions, this is calculated at 15.6 °C (60 °F) and 1 atm for the chemical and the reference fluid, air. For liquid and solid phase conditions, this is calculated based on a reference fluid of water at 4°C at 1 atm, but the with the liquid or solid chemical’s density at the currently specified conditions.

Examples

>>> Chemical('MTBE').SG
0.7428160596603596

property SGg¶

Specific gravity of the gas phase of the chemical, [dimensionless]. The reference condition is air at 15.6 °C (60 °F) and 1 atm (rho=1.223 kg/m^3). The definition for gases uses the compressibility factor of the reference gas and the chemical both at the reference conditions, not the conditions of the chemical.

Examples

>>> Chemical('argon').SGg
1.3795835970877504

property SGl¶

Specific gravity of the liquid phase of the chemical at the specified temperature and pressure, [dimensionless]. The reference condition is water at 4 °C and 1 atm (rho=999.017 kg/m^3). For liquids, SG is defined that the reference chemical’s T and P are fixed, but the chemical itself varies with the specified T and P.

Examples

>>> Chemical('water', T=365).SGl
0.9650065522428539

property SGs¶

Specific gravity of the solid phase of the chemical at the specified temperature and pressure, [dimensionless]. The reference condition is water at 4 °C and 1 atm (rho=999.017 kg/m^3). The SG varries with temperature and pressure but only very slightly.

Examples

>>> Chemical('iron').SGs
7.87774317235069

Tsat(P)[source]¶

property U¶

Internal energy of the chemical at its current temperature and pressure, in units of [J/kg].

This property requires that thermo.chemical.set_thermo ran successfully to be accurate. It also depends on the molar volume of the chemical at its current conditions.

property UNIFAC_Dortmund_groups¶

Dictionary of Dortmund UNIFAC subgroup: count groups for the Dortmund UNIFAC subgroups, as determined by DDBST’s online service.

Examples

>>> Chemical('Cumene').UNIFAC_Dortmund_groups
{1: 2, 9: 5, 13: 1}

property UNIFAC_Q¶

UNIFAC Q (normalized Van der Waals area), dimensionless. Used in the UNIFAC model.

Examples

>>> Chemical('decane').UNIFAC_Q
6.016

property UNIFAC_R¶

UNIFAC R (normalized Van der Waals volume), dimensionless. Used in the UNIFAC model.

Examples

>>> Chemical('benzene').UNIFAC_R
3.1878

property UNIFAC_groups¶

Dictionary of UNIFAC subgroup: count groups for the original UNIFAC subgroups, as determined by DDBST’s online service.

Examples

>>> Chemical('Cumene').UNIFAC_groups
{1: 2, 9: 5, 13: 1}

property Um¶

Internal energy of the chemical at its current temperature and pressure, in units of [J/mol].

This property requires that thermo.chemical.set_thermo ran successfully to be accurate. It also depends on the molar volume of the chemical at its current conditions.

property Van_der_Waals_area¶

Unnormalized Van der Waals area, in units of [m^2/mol].

Examples

>>> Chemical('hexane').Van_der_Waals_area
964000.0

property Van_der_Waals_volume¶

Unnormalized Van der Waals volume, in units of [m^3/mol].

Examples

>>> Chemical('hexane').Van_der_Waals_volume
6.8261966e-05

property Vm¶

Molar volume of the chemical at its current phase and temperature and pressure, in units of [m^3/mol].

Utilizes the object oriented interfaces thermo.volume.VolumeSolid, thermo.volume.VolumeLiquid, and thermo.volume.VolumeGas to perform the actual calculation of each property.

Examples

>>> Chemical('ethylbenzene', T=550, P=3E6).Vm
0.00017758024401627633

property Vmg¶

Gas-phase molar volume of the chemical at its current temperature and pressure, in units of [m^3/mol]. For calculation of this property at other temperatures or pressures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.volume.VolumeGas; each Chemical instance creates one to actually perform the calculations.

Examples

Estimate the molar volume of the core of the sun, at 15 million K and 26.5 PetaPascals, assuming pure helium (actually 68% helium):

>>> Chemical('helium', T=15E6, P=26.5E15).Vmg
4.805464238181197e-07

property Vmg_ideal¶

Gas-phase molar volume of the chemical at its current temperature and pressure calculated with the ideal-gas law, in units of [m^3/mol].

Examples

>>> Chemical('helium', T=300.0, P=1e5).Vmg_ideal
0.0249433878544

property Vml¶

Liquid-phase molar volume of the chemical at its current temperature and pressure, in units of [m^3/mol]. For calculation of this property at other temperatures or pressures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.volume.VolumeLiquid; each Chemical instance creates one to actually perform the calculations.

Examples

>>> Chemical('cyclobutane', T=225).Vml
7.42395423425395e-05

property Vms¶

Solid-phase molar volume of the chemical at its current temperature, in units of [m^3/mol]. For calculation of this property at other temperatures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.volume.VolumeSolid; each Chemical instance creates one to actually perform the calculations.

Examples

>>> Chemical('iron').Vms
7.09593392630242e-06

Weber(V=None, D=None)[source]¶

property Z¶

Compressibility factor of the chemical at its current phase and temperature and pressure, [dimensionless].

Examples

>>> Chemical('MTBE', T=900, P=1E-2).Z
0.9999999999079768

property Zg¶

Compressibility factor of the chemical in the gas phase at the current temperature and pressure, [dimensionless].

Utilizes the object oriented interface and thermo.volume.VolumeGas to perform the actual calculation of molar volume.

Examples

>>> Chemical('sulfur hexafluoride', T=700, P=1E9).Zg
11.140084184207813

property Zl¶

Compressibility factor of the chemical in the liquid phase at the current temperature and pressure, [dimensionless].

Utilizes the object oriented interface and thermo.volume.VolumeLiquid to perform the actual calculation of molar volume.

Examples

>>> Chemical('water').Zl
0.0007385375470263454

property Zs¶

Compressibility factor of the chemical in the solid phase at the current temperature and pressure, [dimensionless].

Utilizes the object oriented interface and thermo.volume.VolumeSolid to perform the actual calculation of molar volume.

Examples

>>> Chemical('palladium').Z
0.00036248477437931853

property absolute_permittivity¶

Absolute permittivity of the chemical at its current temperature, in units of [farad/meter]. Those units are equivalent to ampere^2*second^4/kg/m^3.

Examples

>>> Chemical('water', T=293.15).absolute_permittivity
7.096684821859018e-10

property alpha¶

Thermal diffusivity of the chemical at its current temperature, pressure, and phase in units of [m^2/s].

\[\alpha = \frac{k}{\rho Cp} \]

Examples

>>> Chemical('furfural').alpha
8.696537158635412e-08

property alphag¶

Thermal diffusivity of the gas phase of the chemical at its current temperature and pressure, in units of [m^2/s].

\[\alpha = \frac{k}{\rho Cp} \]

Utilizes the temperature and pressure dependent object oriented interfaces thermo.volume.VolumeGas, thermo.thermal_conductivity.ThermalConductivityGas, and thermo.heat_capacity.HeatCapacityGas to calculate the actual properties.

Examples

>>> Chemical('ammonia').alphag
1.6931865425158556e-05

property alphal¶

Thermal diffusivity of the liquid phase of the chemical at its current temperature and pressure, in units of [m^2/s].

\[\alpha = \frac{k}{\rho Cp} \]

Utilizes the temperature and pressure dependent object oriented interfaces thermo.volume.VolumeLiquid, thermo.thermal_conductivity.ThermalConductivityLiquid, and thermo.heat_capacity.HeatCapacityLiquid to calculate the actual properties.

Examples

>>> Chemical('nitrogen', T=70).alphal
9.444949636299626e-08

property aromatic_rings¶

Number of aromatic rings in a chemical, computed with RDKit from a chemical’s SMILES. If RDKit is not available, holds None.

Examples

>>> Chemical('Paclitaxel').aromatic_rings
3

property atom_fractions¶

Dictionary of atom:fractional occurence of the elements in a chemical. Useful when performing element balances. For mass-fraction occurences, see mass_fractions.

Examples

>>> Chemical('Ammonium aluminium sulfate').atom_fractions
{'H': 0.25, 'S': 0.125, 'Al': 0.0625, 'O': 0.5, 'N': 0.0625}

calc_H(T, P)[source]¶

calc_H_excess(T, P)[source]¶

calc_S(T, P)[source]¶

calc_S_excess(T, P)[source]¶

calculate(T=None, P=None)[source]¶

calculate_PH(P, H)[source]¶

calculate_PS(P, S)[source]¶

calculate_TH(T, H)[source]¶

calculate_TS(T, S)[source]¶

property charge¶

Charge of a chemical, computed with RDKit from a chemical’s SMILES. If RDKit is not available, holds None.

Examples

>>> Chemical('sodium ion').charge
1

draw_2d(width=300, height=300, Hs=False)[source]¶

Interface for drawing a 2D image of the molecule. Requires an HTML5 browser, and the libraries RDKit and IPython. An exception is raised if either of these libraries is absent.

Parameters

widthint: Number of pixels wide for the view
heightint: Number of pixels tall for the view
Hsbool: Whether or not to show hydrogen

Examples

>>> Chemical('decane').draw_2d() 
<PIL.Image.Image image mode=RGBA size=300x300 at 0x...>

draw_3d(width=300, height=500, style='stick', Hs=True, atom_labels=True)[source]¶

Interface for drawing an interactive 3D view of the molecule. Requires an HTML5 browser, and the libraries RDKit, pymol3D, and IPython. An exception is raised if all three of these libraries are not installed.

Parameters

widthint: Number of pixels wide for the view, [pixels]
heightint: Number of pixels tall for the view, [pixels]
stylestr: One of ‘stick’, ‘line’, ‘cross’, or ‘sphere’, [-]
Hsbool: Whether or not to show hydrogen, [-]
atom_labelsbool: Whether or not to label the atoms, [-]

Examples

>>> Chemical('cubane').draw_3d()
<IPython.core.display.HTML object>

property economic_status¶

Dictionary of economic status indicators for the chemical.

Examples

>>> Chemical('benzene').economic_status
["US public: {'Manufactured': 6165232.1, 'Imported': 463146.474, 'Exported': 271908.252}",
 u'1,000,000 - 10,000,000 tonnes per annum',
 u'Intermediate Use Only',
 'OECD HPV Chemicals']

property eos¶

Equation of state object held by the chemical; used to calculate excess thermodynamic quantities, and also provides a vapor pressure curve, enthalpy of vaporization curve, fugacity, thermodynamic partial derivatives, and more; see thermo.eos for a full listing.

Examples

>>> Chemical('methane').eos.V_g
0.02441019502181826

property isentropic_exponent¶

Gas-phase ideal-gas isentropic exponent of the chemical at its current temperature, [dimensionless]. Does not include pressure-compensation from an equation of state.

Examples

>>> Chemical('hydrogen').isentropic_exponent
1.405237786321222

property isobaric_expansion¶

Isobaric (constant-pressure) expansion of the chemical at its current phase and temperature, in units of [1/K].

\[\beta = \frac{1}{V}\left(\frac{\partial V}{\partial T} \right)_P \]

Examples

Radical change in value just above and below the critical temperature of water:

>>> Chemical('water', T=647.1, P=22048320.0).isobaric_expansion
0.34074205839222449

>>> Chemical('water', T=647.2, P=22048320.0).isobaric_expansion
0.18143324022215077

property isobaric_expansion_g¶

Isobaric (constant-pressure) expansion of the gas phase of the chemical at its current temperature and pressure, in units of [1/K].

\[\beta = \frac{1}{V}\left(\frac{\partial V}{\partial T} \right)_P \]

Utilizes the temperature-derivative method of thermo.VolumeGas to perform the actual calculation. The derivatives are all numerical.

Examples

>>> Chemical('Hexachlorobenzene', T=900).isobaric_expansion_g
0.001151869741981048

property isobaric_expansion_l¶

Isobaric (constant-pressure) expansion of the liquid phase of the chemical at its current temperature and pressure, in units of [1/K].

\[\beta = \frac{1}{V}\left(\frac{\partial V}{\partial T} \right)_P \]

Utilizes the temperature-derivative method of thermo.volume.VolumeLiquid to perform the actual calculation. The derivatives are all numerical.

Examples

>>> Chemical('dodecane', T=400).isobaric_expansion_l
0.0011617555762469477

property k¶

Thermal conductivity of the chemical at its current phase, temperature, and pressure in units of [W/m/K].

Utilizes the object oriented interfaces thermo.thermal_conductivity.ThermalConductivityLiquid and thermo.thermal_conductivity.ThermalConductivityGas to perform the actual calculation of each property.

Examples

>>> Chemical('ethanol', T=300).kl
0.16313594741877802
>>> Chemical('ethanol', T=400).kg
0.026019924109310026

property kg¶

Thermal conductivity of the chemical in the gas phase at its current temperature and pressure, in units of [W/m/K].

For calculation of this property at other temperatures and pressures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.thermal_conductivity.ThermalConductivityGas; each Chemical instance creates one to actually perform the calculations.

Examples

>>> Chemical('water', T=320).kg
0.021273128263091207

property kl¶

Thermal conductivity of the chemical in the liquid phase at its current temperature and pressure, in units of [W/m/K].

For calculation of this property at other temperatures and pressures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.thermal_conductivity.ThermalConductivityLiquid; each Chemical instance creates one to actually perform the calculations.

Examples

>>> Chemical('water', T=320).kl
0.6369957248212118

property legal_status¶

Dictionary of legal status indicators for the chemical.

Examples

>>> Chemical('benzene').legal_status
{'DSL': 'LISTED', 'EINECS': 'LISTED', 'NLP': 'UNLISTED', 'SPIN': 'LISTED', 'TSCA': 'LISTED'}

property mass_fractions¶

Dictionary of atom:mass-weighted fractional occurence of elements. Useful when performing mass balances. For atom-fraction occurences, see atom_fractions.

Examples

>>> Chemical('water').mass_fractions
{'H': 0.11189834407236524, 'O': 0.8881016559276347}

property mu¶

Viscosity of the chemical at its current phase, temperature, and pressure in units of [Pa*s].

Utilizes the object oriented interfaces thermo.viscosity.ViscosityLiquid and thermo.viscosity.ViscosityGas to perform the actual calculation of each property.

Examples

>>> Chemical('ethanol', T=300).mu
0.001044526538460911
>>> Chemical('ethanol', T=400).mu
1.1853097849748217e-05

property mug¶

Viscosity of the chemical in the gas phase at its current temperature and pressure, in units of [Pa*s].

For calculation of this property at other temperatures and pressures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.viscosity.ViscosityGas; each Chemical instance creates one to actually perform the calculations.

Examples

>>> Chemical('water', T=320, P=100).mug
1.0431450856297212e-05

property mul¶

Viscosity of the chemical in the liquid phase at its current temperature and pressure, in units of [Pa*s].

For calculation of this property at other temperatures and pressures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.viscosity.ViscosityLiquid; each Chemical instance creates one to actually perform the calculations.

Examples

>>> Chemical('water', T=320).mul
0.0005767262693751547

property nu¶

Kinematic viscosity of the the chemical at its current temperature, pressure, and phase in units of [m^2/s].

\[\nu = \frac{\mu}{\rho} \]

Examples

>>> Chemical('argon').nu
1.3846930410865003e-05

property nug¶

Kinematic viscosity of the gas phase of the chemical at its current temperature and pressure, in units of [m^2/s].

\[\nu = \frac{\mu}{\rho} \]

Utilizes the temperature and pressure dependent object oriented interfaces thermo.volume.VolumeGas, thermo.viscosity.ViscosityGas to calculate the actual properties.

Examples

>>> Chemical('methane', T=115).nug
2.5056924327995865e-06

property nul¶

Kinematic viscosity of the liquid phase of the chemical at its current temperature and pressure, in units of [m^2/s].

\[\nu = \frac{\mu}{\rho} \]

Utilizes the temperature and pressure dependent object oriented interfaces thermo.volume.VolumeLiquid, thermo.viscosity.ViscosityLiquid to calculate the actual properties.

Examples

>>> Chemical('methane', T=110).nul
2.858088468937331e-07

property permittivity¶

Relative permittivity (dielectric constant) of the chemical at its current temperature, [dimensionless].

For calculation of this property at other temperatures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.permittivity.PermittivityLiquid; each Chemical instance creates one to actually perform the calculations.

Examples

>>> Chemical('toluene', T=250).permittivity
2.49775625

property rdkitmol¶

RDKit object of the chemical, without hydrogen. If RDKit is not available, holds None.

For examples of what can be done with RDKit, see their website.

property rdkitmol_Hs¶

RDKit object of the chemical, with hydrogen. If RDKit is not available, holds None.

For examples of what can be done with RDKit, see their website.

property rho¶

Mass density of the chemical at its current phase and temperature and pressure, in units of [kg/m^3].

Utilizes the object oriented interfaces thermo.volume.VolumeSolid, thermo.volume.VolumeLiquid, and thermo.volume.VolumeGas to perform the actual calculation of each property. Note that those interfaces provide output in units of m^3/mol.

Examples

>>> Chemical('decane', T=550, P=2E6).rho
498.67008448640604

property rhog¶

Gas-phase mass density of the chemical at its current temperature and pressure, in units of [kg/m^3]. For calculation of this property at other temperatures or pressures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.volume.VolumeGas; each Chemical instance creates one to actually perform the calculations. Note that that interface provides output in molar units.

Examples

Estimate the density of the core of the sun, at 15 million K and 26.5 PetaPascals, assuming pure helium (actually 68% helium):

>>> Chemical('helium', T=15E6, P=26.5E15).rhog
8329.27226509739

Compared to a result on Wikipedia of 150000 kg/m^3, the fundamental equation of state performs poorly.

>>> He = Chemical('helium', T=15E6, P=26.5E15)
>>> He.VolumeGas.method_P = 'IDEAL'
>>> He.rhog
850477.8

The ideal-gas law performs somewhat better, but vastly overshoots the density prediction.

property rhogm¶

Molar density of the chemical in the gas phase at the current temperature and pressure, in units of [mol/m^3].

Utilizes the object oriented interface and thermo.volume.VolumeGas to perform the actual calculation of molar volume.

Examples

>>> Chemical('tungsten hexafluoride').rhogm
42.01349946063116

property rhol¶

Liquid-phase mass density of the chemical at its current temperature and pressure, in units of [kg/m^3]. For calculation of this property at other temperatures and pressures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.volume.VolumeLiquid; each Chemical instance creates one to actually perform the calculations. Note that that interface provides output in molar units.

Examples

>>> Chemical('o-xylene', T=297).rhol
876.9946785618097

property rholm¶

Molar density of the chemical in the liquid phase at the current temperature and pressure, in units of [mol/m^3].

Utilizes the object oriented interface and thermo.volume.VolumeLiquid to perform the actual calculation of molar volume.

Examples

>>> Chemical('nitrogen', T=70).rholm
29937.20179186975

property rhom¶

Molar density of the chemical at its current phase and temperature and pressure, in units of [mol/m^3].

Utilizes the object oriented interfaces thermo.volume.VolumeSolid, thermo.volume.VolumeLiquid, and thermo.volume.VolumeGas to perform the actual calculation of each property. Note that those interfaces provide output in units of m^3/mol.

Examples

>>> Chemical('1-hexanol').rhom
7983.414573003429

property rhos¶

Solid-phase mass density of the chemical at its current temperature, in units of [kg/m^3]. For calculation of this property at other temperatures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.volume.VolumeSolid; each Chemical instance creates one to actually perform the calculations. Note that that interface provides output in molar units.

Examples

>>> Chemical('iron').rhos
7869.999999999994

property rhosm¶

Molar density of the chemical in the solid phase at the current temperature and pressure, in units of [mol/m^3].

Utilizes the object oriented interface and thermo.volume.VolumeSolid to perform the actual calculation of molar volume.

Examples

>>> Chemical('palladium').rhosm
112760.75925577903

property rings¶

Number of rings in a chemical, computed with RDKit from a chemical’s SMILES. If RDKit is not available, holds None.

Examples

>>> Chemical('Paclitaxel').rings
7

set_TP_sources()[source]¶

set_constant_sources()[source]¶

set_constants()[source]¶

set_eos(T, P, eos=<class 'thermo.eos.PR'>)[source]¶

set_ref(T_ref=298.15, P_ref=101325, phase_ref='calc', H_ref=0, S_ref=0)[source]¶

set_thermo()[source]¶

property sigma¶

Surface tension of the chemical at its current temperature, in units of [N/m].

For calculation of this property at other temperatures, or specifying manually the method used to calculate it, and more - see the object oriented interface thermo.interface.SurfaceTension; each Chemical instance creates one to actually perform the calculations.

Examples

>>> Chemical('water', T=320).sigma
0.06855002575793023
>>> Chemical('water', T=320).SurfaceTension.solve_property(0.05)
416.8307110842183

property solubility_parameter¶

Solubility parameter of the chemical at its current temperature and pressure, in units of [Pa^0.5].

\[\delta = \sqrt{\frac{\Delta H_{vap} - RT}{V_m}} \]

Calculated based on enthalpy of vaporization and molar volume. Normally calculated at STP. For uses of this property, see thermo.solubility.solubility_parameter.

Examples

>>> Chemical('NH3').solubility_parameter
24766.329043856073

Legacy Chemicals (thermo.chemical)¶

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