Properties of Gases

Notes:

The critical temperature is the maximum temperature at which a gas can be liquified. (above this temperature a liquid cannot exist)
The critical pressure is the pressure to liquify the gas at this temperature.
The critical density is the resulting density at these conditions
The viscosity values are in μP to obtain μPa.s = μN.s/m² divide table values by 10
The properties ** are temperature related..

Physical Properties at ST & P

Properties are generally at Standard Temperature and Pressure (273 K, 1 atm)

Gas	Formula	MW	Density **	Freezing Temp	Boiling Temp	Critical Temp	Critical Pressure	Critical Density	Thermal Conductivity **	Dynamic Viscosity **
			kg/m3	Deg K	Deg. K	Deg. K	x 105 Pa	kg/m3	(mW/mK)	μP
Acetylene	2H2	26.04	1.173	192.44	189.04	308.36	61.39	230.41	21.3	10.22
Air		29	1.293	59.15	78.67	132.45	37.7	316.56	24.1	181
Ammonia	Nh4	17	0.77	83.84	87.32	150.1	112.8	235.29	24.2	10.13
Argon	A	39.95	1.783	84	87	151	48.98	531	16.2	223
n-Butane	C4H10	58.1	2.672	134.9	272.69	425.22	37.97	227.95	13.77	69.02
Carbon Dioxide	CO2	44	1.977	216		33	74	460	14.5	147
Carbon Monoxide	CO2	28.01	1.25	68.19	81.74	132.96	34.99	270.27	24.6	177.5
Chlorine	Cl2	70.9	3.214	172.16	239.16	417.19	77.1	571.43	8.034	123
Ethane	C2H6	30.07	1.356	90.39	184.59	305.06	48.8	203	21.18	93.76
Ethylene	C2H2	28.05	1.26	104.04	169.45	282.2	50.4	214.13	17.97	93.76
Helium	He	4.03	0.178	1.89	4.26	5.24	2.3	69.93	146	187
Hydrochloric Acid	HCl	36.5	1.639	159	188	324	83.1	450.45	13.43	134
Hydrogen	H2	2.02	0.09	14	20.4	33.23	13	31.4	168.4	88
Hydrogen Sulphide	H2S	34.1	1.538	187.7	212.8	373.57	89.63	346.02	12.65	11.71
Methane	CH4	16	0.716	90.71	111.7	190.6	46.04	161.58	30.01	103.3
Methyl Chloride	CH2Cl	50.5	2.308	175.49	248.97	416.29	66.8	352.86	179.2	100.4
Natural Gas		19.5	0.862
Neon	Ne		0.902	24.59	27.13	44	26.53	483.79	46.11	297
Nitric Oxide	NO	30	1.389	112.19	121.42	180.19	64.8	518.13	23.69	178
Nitrogen	N2	28	1.25				33.9	311	24.3	174
Nitrous Oxide	N2O	44	1.978	182.37	184.71	309.61	72.45	451.67	15.52	134.9
Oxygen	O2	32	1.429	54	90	154	50.4	430	24.4	200
Propane	C3H8	44.1	2.019	85.56	231.15	369.86	42.49	220.36	15.91	75.98
Sulphur Dioxide	SO2	64.1	2.927	200.04	263.17	430.79	78.84	524.93	8.42	117.9

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Thermodynamic Properties and NT & P

Properties in this generally at Normal Temperature and Pressure (293 K, 1 atm)
The properties are mostly temperature related

Gas	Formula	MW	Density	R	Cp	Cv	Cp/Cv= γ
			(kg/m3)	kJ/(kg.K)	kJ/(kg.K)	kJ/(kg.K)
Acetylene	2H2	26	1.0925	0.32	1.465	1.127	1.3
Air		29	1.2045	0.287	1.009	0.721	1.4
Ammonia	Nh4	17	0.7179	0.49	2.19	1.659	1.32
Argon	A	39.9	1.661	0.208	0.519	0.311	1.67
n-Butane	C4H10	58.1	2.4897	0.143	1.654	1.49	1.11
Carbon Dioxide	CO2	44	1.8417	0.189	0.858	0.66	1.3
Carbon Monoxide	CO2	28	1.1648	0.297	1.017	0.726	1.4
Chlorine	Cl2	70.9	2.9944	0.117	0.481	0.362	1.33
Ethane	C2H6	30	1.2635	0.277	1.616	1.325	1.22
Ethylene	C2H2	28	1.1744	0.296	1.675	1.373	1.22
Helium	He	4	0.1663	2.078	5.234	3.153	1.66
Hydrochloric Acid	HCl	36.5	1.5273	0.228	0.8	0.567	1.41
Hydrogen	H2	2	0.0837	4.126	14.319	10.155	1.41
Hydrogen Sulphide	H2S	34.1	1.4334	0.243	1.017	0.782	1.3
Methane	CH4	16	0.6673	0.519	2.483	1.881	1.32
Methyl Chloride	CH2Cl	50.5	2.15	0.165	1.005	0.838	1.2
Natural Gas		19.5	0.8034	0.426	2.345	1.846	1.27
Neon	Ne	20.18	0.84
Nitric Oxide	NO	30	1.2941	0.277	0.967	0.691	1.4
Nitrogen	N2	28	1.1648	0.297	1.034	0.733	1.41
Nitrous Oxide	N2O	44	1.8429	0.189	0.925	0.706	1.31
Oxygen	O2	32	1.331	0.26	0.909	0.649	1.4
Propane	C3H8	44.1	1.8814	0.188	1.645	1.43	1.15
Sulphur Dioxide	SO2	64.1	2.727	0.129	0.645	0.512	1.26