Estimate density from the Rackett equation correlation.
Ethylene (C₂H₄) is the world's most produced organic chemical (~200 million tonnes/year). Its liquid density varies from ~654 kg/m³ at the melting point (−169.2 °C) to ~568 kg/m³ at the normal boiling point (−103.7 °C), reaching the critical density of 214 kg/m³ at Tc = 9.2 °C, Pc = 50.4 atm. The Rackett equation ρ = Mc/(Vc × Z_RA^((1-T/Tc)^(2/7))) provides a reliable estimate of saturated liquid density. Ethylene is the monomer for polyethylene (PE), the world's most common plastic. It is also a precursor to ethylene oxide, ethylene glycol (antifreeze), vinyl chloride (PVC), and styrene. In agriculture, ethylene is a plant hormone that triggers fruit ripening.