Some Physical Properties of Compressed Gases. VI. The Fugacity of Carbon Dioxide

The Michels' compressibility data for carbon dioxide are smoothed and interpolated by graphical methods, and the fugacity is computed at certain integral pressures. The temperature range is from 0° to 150°C, and the pressure range from 0 to the neighborhood of 3000 atmos. Along all isotherms, the fugacity at first drops below the pressure, the ratio $\frac{f}{p}$ decreasing with $p-\mathrm{a}$ phenomenon well known and explained by the attractive forces of the molecules. The minimum in $\frac{f}{p}$ is reached at or near 600 atmos. for all isotherms above critical. With further increase in pressure, the ratio $\frac{f}{p}$ increases, so that the fugacity eventually equals the pressure and thereafter exceeds it. At 50°, $f=p \mathrm{at} 2435$ atmos.; at 150°, $f=p \mathrm{at} 1675$ atmos.