Chapter 12, Problem 99A

Interpretation Introduction

Interpretation:

The conditions under which supercritical carbon dioxide is formed needs to be determined.

Concept introduction:

Supercritical carbon dioxide is liquid carbon dioxide which is formed above critical temperature and critical pressure of carbon dioxide gas.

Answer to Problem 99A

Above $304.3K$ temperature and $72.8atm$ pressure supercritical carbon dioxide is formed.

Explanation of Solution

Supercritical carbon dioxide is a liquid form of $C{O}_2$ used in the food industry to decaffeinate tea, coffee, and coals, as well as in the pharmaceutical industry to form polymer micro-particles used in drug delivery systems.

When a gas is made to expand above its critical temperature and critical pressure it changes to a liquid. So when carbon dioxide is expanded above its critical temperature i.e. $304.3K$ and critical pressure i.e. $72.8atm$ it becomes supercritical carbon dioxide means liquid carbon dioxide.

Conclusion

Above $304.3K$ temperature and $72.8atm$ pressure carbon dioxide behaves as supercritical fluid.