Dalton’s Law of Partial Pressure

Dalton’s Law

As we think of rules that we inadvertently follow every day without even realizing it like speed limits and wearing seatbelts, respiratory therapists must remember that there are gas laws we follow every day without realizing it also. This paper will focus on a gas law called Dalton’s law of partial pressures. For respiratory therapists to fully understand the importance of Dalton’s law, we must explain what this law states, how it applies to respiratory care, and what advancements in technology have been made to modify the use of this law.

In the early 1800’s, a scientist by the name of John Dalton developed a theory which we now refer to as Dalton’s law of partial pressure. John Dalton developed this law by experimenting with the gases in the atmosphere. “Dalton's experiments on gases led to his discovery that the total pressure of a mixture of gases amounted to the sum of the partial pressures that each individual gas exerted while occupying the same space”(A+E Networks, 2013). Mathematically, Dalton explained this law by stating, Ptotal= P1+P2+P3……Pn. These preliminary experiments that Dalton performed were based on the original 760 torr or 760 mmHg that had been earlier discovered by Torricelli. Dalton then realized that the 760 mmHg in the atmosphere is made up of gases such as oxygen, nitrogen, carbon dioxide, and a few other trace gases. The pressure given off by each of these gases is considered to be the partial pressure of the total atmospheric pressure. The percentages of these gases in the atmosphere at sea level are nitrogen 78.08%, oxygen 20.95%, carbon dioxide 0.03 %, and remaining trace gases 0.94% which make up a total of 100% in the atmosphere.

As we think about Dalton’s law of partial pressures...

... middle of paper ...

... partial pressures. Over many years of development, we now widely use oxygen therapy to treat individuals with altitude sickness, and can use hyperbaric oxygen therapy to treat divers affected by decompression sickness. As respiratory therapists, we owe the success of these two treatments to a scientist by the name of John Dalton for the development of Dalton’s law of partial pressures.

A E Networks. (2013). John dalton biography. Retrieved from http://www.biography.com/people/john-dalton-9265201?page=1 Harvard Health Publications. (2013). Decompression sickness. Retrieved from http://www.drugs.com/health-guide/decompression-sickness.html Pendleton , L. D. (1999, November 07). When humans fly high:what pilots should know about high altitude physiology, hypoxia, and rapid decompression. Retrieved from http://www.avweb.com/news/aeromed/181893-1.html?redirected=1