###### Abstract  
Understanding the density of CO\({}_{2}\) + \(n\)-decane is crucial for designing and operating CO\({}_{2}\) capture, transport, and storage. The safety and effectiveness of CO\({}_{2}\) burial is directly affected by the density of CO\({}_{2}+n\)-decane mixtures. The liquid densities of CO\({}_{2}\)(I) + \(n\)-decane(2) mixtures with mole fractions of CO\({}_{2}\)\(x_{1}\) = 0, 0.2032, 0.4434, 0.7589, and 0.8947 were measured using a vibrating tube densimeter. The combined expanded uncertainties of density with a level of confidence of 0.95 are estimated to be 0.6 kg\(\cdot\)m\({}^{-3}\). A total of 221 compressed liquid densities of CO\({}_{2}\)(I) + \(n\)-decane(2) mixtures along the five isotherms between \(T\) = (283 and 363) K with pressures up to 100 MPa were presented. The densities of mixtures were correlated by the modified Tait equation, resulting in absolute average deviations between the experimental and calculated values of 0.028%, 0.013%, 0.017%, 0.044%, and 0.042%. In addition, the isothermal compressibility, isobaric thermal expansivity, and excess molar volume were derived from the modified Tait equation.  
CO\({}_{2}\); \(n\)-decane; compressed liquid density; vibrating tube densimeter; derived thermodynamics properties +
Footnote †: journal: Applied Sciences  
A change in the density of CO\({}_{2}\) + \(n\)-decane mixtures will influence the movement of CO\({}_{2}\) under the oil reservoir, which has a significant impact on the oil displacement efficiency and the safe storage of CO\({}_{2}\). Extensive experimental density data for CO\({}_{2}\) + \(n\)-decane mixtures have been reported [14; 15]. The densities of CO\({}_{2}\) + \(n\)-decane mixtures have been investigated, as shown in Table 1. [PERSON] and [PERSON] [16] measured the density of CO\({}_{2}\) + \(n\)-decane mixtures at 310-403 K, and 7-35 MPa with a vibrating tube densimeter (VTD). [PERSON] et al. [17] used a VTD to measure the densities of CO\({}_{2}\) + \(n\)-decane mixtures at 308-368 K and 20-40 MPa. [PERSON] et al. [18] carried out tests on the density of CO\({}_{2}\) + \(n\)-decane mixtures at 313-363 K and 1-25 MPa using a VTD. [PERSON] et al. [19] reported the densities of CO\({}_{2}\) + \(n\)-decane mixtures measured by a VTD at 283-398 K and 10-120 MPa. [PERSON] et al. [11] studied the densities of CO\({}_{2}\) + \(n\)-decane mixtures at 303-353 K and 8-19 MPa with a magnetic suspension balance (MSB). [PERSON] et al. [20] and coworkers ([PERSON] et al. [21]) investigated saturated liquid density at 323 K and 373 K using a VTD. [PERSON] et al. [22] provided the density of CO\({}_{2}\) + \(n\)-decane mixtures at 313-410 K and 3-6 MPa. [PERSON] et al. [23] conducted tests on the density of CO\({}_{2}\) + \(n\)-decane mixtures at 283-393 K and 10-100 MPa using a VTD. [PERSON] et al. [24] measured the densities of CO\({}_{2}\) + \(n\)-decane mixtures using a VTD at 303-373 K and 1-80 MPa. The literature survey shows that density data for CO\({}_{2}\) + \(n\)-decane mixtures mainly focus on low-pressure areas. The density data for mixtures at high pressures are still insufficient.  
In this study, the densities of CO\({}_{2}\) + \(n\)-decane mixtures were measured with a VTD at temperatures ranging from 283 K to 363 K, and pressures between 10 and 100 MPa. The density data in this study were analyzed using the modified Tait equation. Furthermore, the thermodynamics properties of the mixtures were derived. The purpose of this study is to provide a basis of data and theoretical support for the CO\({}_{2}\) sequestration and resource utilization.