Vapor pressures of isobutane and CF4. The paramateres of the Antoine equation were taken from the following NIST pages. Isobutane: https://webbook.nist.gov/cgi/cbook.cgi?ID=C75285&Mask=4&Type=ANTOINE&Plot=on CF4: https://webbook.nist.gov/cgi/cbook.cgi?ID=C75730&Mask=4&Type=ANTOINE&Plot=on MODIFIED ATTACHMENT FILES: vertical axes were fixed