Nitrous Oxide
Overview
Nitrous oxide (NYE-truss OX-side) is also known as dinitrogen oxide, dinitrogen monoxide, nitrogen monoxide, and laughing gas. It is a colorless, nonflammable gas with a sweet odor. Its common name of laughing gas is derived from the fact that it produces a sense of light-headedness when inhaled. The gas is widely used as an anesthetic, a substance that reduces sensitivity to pain and discomfort.
Key Facts
Other Names:
See Overview.
Formula:
N2O
Elements:
Nitrogen; oxygen
Compound Type:
Nonmetallic oxide (inorganic)
State:
Gas
Molecular Weight:
44.01 g/mol
Melting Point:
−90.8°C (−131°F)
Boiling Point:
−88.48°C (−127.3°F)
Solubility:
Slightly soluble in water; soluble in ethyl alcohol and ether
Nitrous oxide was probably first produced by the English chemist and physicist Robert Boyle (1627–1691), although he did not recognize the new compound he had found. Credit for the discovery of nitrous oxide is, therefore, usually given to the English chemist Joseph Priestley (1733–1804), who produced the gas in 1772 and named it "nitrous air." Other early names used for the gas include "gaseous of azote" (nitrogen) and "oxide of speton." The most complete experiments on the gas were conducted by the English chemist and physicist Sir Humphry Davy (1778–1829), who tested nitrous oxide on himself and his friends. He found that the gas could lessen pain and discomfort and provided a sense of relaxation and well-being. Before long, doctors were making use of Davy's discovery by using nitrous oxide as an anesthetic.
The public found other uses for the gas as well. During the Victorian period in England, members of the upper class often held laughing gas parties at which people gathered to inhale nitrous oxide as a recreational drug, rather than for any therapeutic purpose. In the United States, the showman P. T. Barnum (1810–1891) created a sideshow exhibit in which people were invited to test the effects of inhaling nitrous oxide. After seeing a demonstration of this kind, the American dentist Horace Wells (1815–1848) first used nitrous oxide as an anesthetic on his patients.
In 1868, the American surgeon Edmund Andrews (1824–1904) extended the use of nitrous oxide as an anesthetic for his surgical patients. He mixed the gas with oxygen to ensure that patients received enough oxygen while receiving the anesthetic. The gas is still widely used by dentists as a safe and relatively pleasant way of helping patients endure the discomfort of drilling and other dental procedures.
How It Is Made
The most common commercial method of producing nitrous oxide involves the controlled heating of ammonium nitrate (NH4NO3). The compound decomposes to form nitrous oxide and water. The reaction is essentially the same one originally used by Priestley in 1772. Although an efficient means of producing the gas, the reaction must be carried out with extreme care as ammonium nitrate has a tendency to decompose explosively when heated. Nitrous oxide can also be produced by the decomposition of nitrates (compounds containing the NO3 radical), nitrites (compounds containing the NO2) radical, or nitriles (compounds containing the CH− radical).
Common Uses and Potential Hazards
Nitrous oxide is best known and most widely used as an anesthetic. Its use is limited primarily to dental procedures and minor surgeries. Dentists favor nitrous oxide as an anesthetic because the gas does not make patients completely unconscious and does not require an anesthesiologist to administer it. Nitrous oxide works as an anesthetic by blocking neurotransmitter receptors in the brain, preventing pain messages from being transmitted.
Interesting Facts
- Humphry Davy proposed the name laughing gas for nitrous oxide.
- In the United Kingdom, nitrous oxide is often used as an anesthetic for women about to give birth.
- In the 1830s, Samuel Colt (1814–1862), inventor of the Colt 45 revolver, toured North America, giving laughing gas demonstrations.
Nitrous oxide is also used as a fuel additive in racing cars, in which case it is often referred to as nitro. The gas is injected into the intake manifold where it mixes with air and fuel vapors. Since it breaks down at the high temperatures in the car's engine, it provides additional oxygen to increase the efficiency with which the fuel burns. During World War II, pilots used nitrous oxide for a similar purpose in their airplanes.
Some additional uses of nitrous oxide include:
- As a propellant in food aerosols;
- For the detection of leaks;
- As a packaging gas for potato chips and other snack foods, preventing moisture from making the product become stale;
- In the preparation of other nitrogen compounds; and
- As an oxidizing agent for various industrial processes.
Nitrous oxide is safe to use in moderate amounts under controlled conditions. Some people use the compound as a recreational drug, however, hoping to get a "high" from inhaling it. One risk of this practice is that the inhalation of nitrous oxide may reduce the amount of oxygen a person receives. Also, some long-term health effects, such as anemia (low red blood cell count) and neuropathy (damage to the nerves), have been associated with excessive use of the compound. The use of nitrous oxide for recreational purposes is a crime in some states.
Words to Know
A substance that reduces sensitivity to pain and discomfort. A compound that includes the radical consisting of one nitrogen atom and three oxygen atoms (NO3). A compound that includes the radical consisting of one nitrogen atom and two oxygen atoms (NO2). A group of atoms bonded together that act like a single entity in chemical reactions.For Further Information
"Gas Data: Nitrous Oxide." Air Liquide. http://www.airliquide.com/en/business/products/gases/gasdata/index.asp?GasID=55 (accessed on October 20, 2005).
Neff, Natalie. "No Laughing Matter." Auto Week (May 19, 2003): 30.
"Nitrogen Oxide." Center for Advanced Microstructures and Devices, Louisiana State University. http://www.camd.lsu.edu/msds/n/nitrous_oxide.htm#Synonyms (accessed on October 20, 2005).
"Occupational Safety and Health Guideline for Nitrous Oxide." Occupational Safety and Health Administration. http://www.osha.gov/SLTC/healthguidelines/nitrousoxide/recognition.html (accessed on October 20, 2005).
Pae, Peter. "Sobering Side of Laughing Gas." Washington Post (September 16, 1994): B1.
See Also
Ammonium Nitrate
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