Gas Charts

Relative Thermal Conductivity of Gases

Name	Chemical Formula	Conductivity (Relative to Air)
Air		1.00
Ammonia	NH3	0.92
Argon	Ar	0.68
Butane	C4H10	0.60
Carbon Dioxide	CO2	0.62
Carbon Monoxide	CO	0.97
Ethane	C2H6	0.79
Helium	He	5.84
Hydrogen	H2	7.07
Krypton	Kr	0.37
Methane	CH4	1.29
Neon	Ne	1.87
Nitric Oxide	NO	0.99
Nitrogen	N2	1.00
Nitrogen Dioxide	NO2 or N2O4	1.51
Nitrous Oxide	N2O	0.65
Oxygen	O2	1.02
Sulfur Dioxide	SO2	0.38
Water Vapor	H2O	0.67

Typical Gases Used

Flow Rate of 50 cm3/min
Test	Preparation Gas	Carrier Gas	Loop Gas	Other
TPR Experiment	Argon	10% H2 in Argon	N/A
Calibration	N/A		Argon	TCD Level Calibration
TPD Ammonia	Helium or 15% NH3 in Helium	Helium	N/A
Calibration	N/A		NH3 in Helium	TCD Level Calibration
TPD Hydrogen	10% H2 in Argon	Argon	N/A	Calibration
Calibration	N/A		10% H2 in Argon	TCD Level Calibration
TPD Oxygen	10% O2 in Helium	Helium	N/A
Calibration	N/A		10% O2 in Helium	TCD Level Calibration
TPO Experiment	Helium	10% O2 in Helium	N/A
Calibration	N/A		Helium	TCD Level Calibration
H2 Pulse Chemisorption	10% H2 in Argon	Argon	10% H2 in Argon
CO Pulse Chemisorption		Helium	10% CO in Helium
Calibration	Not Required
BET Surface Area	Helium	30% N2 in Helium	N/A
Calibration	N/A			User-defined manual injections of N2 (0.5, 1.0, 1.5, and 2.0 cm3)

Gas Conversion Constants

Dynamic analysis uses a Mass Flow Controller (MFC) to control the flow of gases. The MFC requires a conversion constant for each gas or gas mixture to compensate for variations in gas flows resulting from variations in the properties of gases. A default gas table containing MFC conversion constants is included on the Options menu. The following table provides a more complete list of gases and their conversion constants.

Gas Conversion Constants for the MFC

Gas	Symbol	MFC Conversion Constant (H2 = 1.000)
Acetylene	C2H2	0.6535
Air (mixture)		0.9901
Allene	C3H4	0.4752
Ammonia	NH3	0.7822
Argon	Ar	1.3861
Arsine	A5H3	0.7525
Boron Trichloride	BCl3	0.4356
Boron Trifluoride	BF3	0.5743
Bromine Pentafluoride	BrF5	0.2871
Bromine Trifluoride	BrF3	0.4356
Butane	C4H10	0.2871
Butene	C4H8	0.3267
Carbon Dioxide	CO2	0.7723
Carbon Monoxide	CO	0.9802
Carbon Tetracloride	CCl4	0.3465
Carbon Tetrafluoride	CF4	0.4752
Carbonyl Fluoride	COF2	0.2673
Carbonyl Sulfide	COS	0.6733
Chlorine	Cl2	0.8218
Chloroform	CHCl3	0.4356
Chlorine Trifluoride	ClF3	0.4257
Cyanogen	C2N2	0.4950
Cyclopropane	C3H6	0.5050
Deuterium	D2	0.9901
Diborane	B2H6	0.5446
Dichlorosilane	SiH2Cl2	0.4356
Dimethylamine	(CH3)2NH	0.6634
Dimethylether	(CH3)2O	0.5842
Ethane	C2H6	0.5446
Ethyl Chloride	C2H5Cl	0.2871
Ethylene	C2H4	0.6139
Ethylene Oxide	C2H4O	0.5842
Fluorine	F2	0.9208
Fluroform	CHF3	0.5644
Freon 11	CCl3F	0.3762
Freon 12	CCl3F2	0.3861
Freon 13	CClF3	0.4257
Freon 13 B1	CBrF3	0.4059
Freon 14	CF4	0.4703
Freon 21	CHCl2F	0.4554
Freon 22	CHClF2	0.5050
Freon 23	CHF3	0.5644
Freon 113	CCl2F-CClF2	0.2277
Freon 114	CCl2F4-CClF2	0.2554
Freon 115	CClF2-CF3	0.2713
Freon 116	CF3-CF3	0.2277
Germane	GeH4	0.6436
Helium	He	1.3762
Hexamethyldisizane	HMDS	0.1386
Hydrogen	H2	1.0000
Hydrogen Bromide	HBr	0.9703
Hydrogen Chloride (Dry)	HCl	0.9802
Hydrogen Fluoride	HF	0.9901
Hydrogen Iodide	HI	0.9505
Hydrogen Selenide	H2Se	0.8317
Hydrogen Sulfide	H2S	0.8416
Isobutane	C4H10	0.3069
Isobutylene	C4H8	0.3366
Krypton	Kr	1.3762
Methane	CH4	0.8020
Methylamine	CH3NH2	0.5644
Methyl Bromide	CH3Br	0.6436
Methyl Chloride	CH3Cl	0.6832
Methyl Fluoride	CH3F	0.7525
Methyl Mercaptan	CH4S	0.5842
Neon	Ne	1.3861
Nitric Oxide	NO	0.9901
Nitrogen	N2	0.9950
Nitrogen Dioxide	NO2	0.7525
Nitrogen Trioxide	N2O3	0.4356
Nitrogen Trifluoride	NF3	0.5446
Nitrous Oxide	N2O	0.7426
Oxygen	O2	0.9802
Ozone	O3	0.7327
Pentaborane	B5Hg	0.2871
n Pentane	C5H12	0.2376
Perchloryl Fluoride	ClO3F	0.4455
Phosgene	COCl2	0.5050
Phosphine	PH3	0.7822
Phosphorous Pentafluoride	PF5	0.3465
Propane	C3H8	0.3861
Propylene (Propene)	C3H6	0.4653
Silane	SiH4	0.6733
Silicon Tetrachloride	SiCl4	0.3168
Silicon Tetrafluoride	SiF4	0.3960
Sulfur Dioxide	SO2	0.7228
Sulfur Hexafluoride	SF6	0.2970
Trichlorosilane	Cl3HSi	0.3267
Trimethylamine	(CH3)3N	0.3168
Tungsten Hexafluoride	WF6	0.2871
Uranium Hexafluoride	UF6	0.2178
Vinyl Bromide	C2H3Br	0.5248
Vinyl Chloride	C2H3Cl	0.5347
Vinyl Fluoride	C2H3F	0.5743
Xenon	Xe	1.3762