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Louis Plack Hammett
Louis Plack Hammett (April 7, 1894 – February 9, 1987) was an American physical chemist. He is known for the Hammett equation, which relates reaction rates to equilibrium constants for certain classes of organic reactions involving substituted aromatic compounds. He is also known for his research into superacids and his development of a scheme for comparing their acidities based on what is now known as the Hammett acidity function. The Curtin–Hammett principle bears his name. The awards he obtained included the Priestley Medal in 1961,the Willard Gibbs Award in 1961, the National Medal of Science in 1967, and in 1975 the Barnard Medal for Meritorious Service to Science. Hammett grew up in Portland, Maine, and studied in Harvard and Switzerland. He earned his Ph.D. at Columbia University. He authored an influential textbook on physical organic chemistry,Hammett, Louis P. (1940) ''Physical Organic Chemistry'' New York: McGraw Hill. and is credited with coining the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Chemistry
Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mechanics, analytical dynamics and chemical equilibria. Physical chemistry, in contrast to chemical physics, is predominantly (but not always) a supra-molecular science, as the majority of the principles on which it was founded relate to the bulk rather than the molecular or atomic structure alone (for example, chemical equilibrium and colloids). Some of the relationships that physical chemistry strives to resolve include the effects of: # Intermolecular forces that act upon the physical properties of materials ( plasticity, tensile strength, surface tension in liquids). # Reaction kinetics on the rate of a reaction. # The identity of ions and the electrical conductivity of materials. # Surface science and electrochemistry of cell membrane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hammett Acidity Function
The Hammett acidity function (''H''0) is a measure of acidity that is used for very concentrated solutions of strong acids, including superacids. It was proposed by the physical organic chemist Louis Plack Hammett and is the best-known acidity function used to extend the measure of Brønsted–Lowry acidity beyond the dilute aqueous solutions for which the pH scale is useful. In highly concentrated solutions, simple approximations such as the Henderson–Hasselbalch equation are no longer valid due to the variations of the activity coefficients. The Hammett acidity function is used in fields such as physical organic chemistry for the study of acid-catalyzed reactions, because some of these reactions use acids in very high concentrations, or even neat (pure).Gerrylynn K. Roberts, Colin Archibald Russell. ''Chemical History: Reviews of the Recent Literature''. Royal Society of Chemistry, 2005. . Definition The Hammett acidity function, ''H''0, can replace the pH in concentrated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1987 Deaths
File:1987 Events Collage.png, From top left, clockwise: The MS Herald of Free Enterprise capsizes after leaving the Port of Zeebrugge in Belgium, killing 193; Northwest Airlines Flight 255 crashes after takeoff from Detroit Metropolitan Airport, killing everyone except a little girl; The King's Cross fire kills 31 people after a fire under an escalator Flashover, flashes-over; The MV Doña Paz sinks after colliding with an oil tanker, drowning almost 4,400 passengers and crew; Typhoon Nina (1987), Typhoon Nina strikes the Philippines; LOT Polish Airlines Flight 5055 crashes outside of Warsaw, taking the lives of all aboard; The USS Stark is USS Stark incident, struck by Iraq, Iraqi Exocet missiles in the Persian Gulf; President of the United States, U.S. President Ronald Reagan gives a famous Tear down this wall!, speech, demanding that Soviet Union, Soviet leader Mikhail Gorbachev tears down the Berlin Wall., 300x300px, thumb rect 0 0 200 200 Zeebrugge disaster rect 200 0 400 200 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Academics From Portland, Maine
An academy (Attic Greek: Ἀκαδήμεια; Koine Greek Ἀκαδημία) is an institution of secondary or tertiary higher learning (and generally also research or honorary membership). The name traces back to Plato's school of philosophy, founded approximately 385 BC at Akademia, a sanctuary of Athena, the goddess of wisdom and skill, north of Athens, Greece. Etymology The word comes from the ''Academy'' in ancient Greece, which derives from the Athenian hero, ''Akademos''. Outside the city walls of Athens, the gymnasium was made famous by Plato as a center of learning. The sacred space, dedicated to the goddess of wisdom, Athena, had formerly been an olive grove, hence the expression "the groves of Academe". In these gardens, the philosopher Plato conversed with followers. Plato developed his sessions into a method of teaching philosophy and in 387 BC, established what is known today as the Old Academy. By extension, ''academia'' has come to mean the accumulation, de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbia University Faculty
Columbia may refer to: * Columbia (personification), the historical female national personification of the United States, and a poetic name for America Places North America Natural features * Columbia Plateau, a geologic and geographic region in the U.S. Pacific Northwest * Columbia River, in Canada and the United States ** Columbia Bar, a sandbar in the estuary of the Columbia River ** Columbia Country, the region of British Columbia encompassing the northern portion of that river's upper reaches ***Columbia Valley, a region within the Columbia Country ** Columbia Lake, a lake at the head of the Columbia River *** Columbia Wetlands, a protected area near Columbia Lake ** Columbia Slough, along the Columbia watercourse near Portland, Oregon * Glacial Lake Columbia, a proglacial lake in Washington state * Columbia Icefield, in the Canadian Rockies * Columbia Island (District of Columbia), in the Potomac River * Columbia Island (New York), in Long Island Sound Populated places * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbia University Alumni
Columbia may refer to: * Columbia (personification), the historical female national personification of the United States, and a poetic name for America Places North America Natural features * Columbia Plateau, a geologic and geographic region in the U.S. Pacific Northwest * Columbia River, in Canada and the United States ** Columbia Bar, a sandbar in the estuary of the Columbia River ** Columbia Country, the region of British Columbia encompassing the northern portion of that river's upper reaches ***Columbia Valley, a region within the Columbia Country ** Columbia Lake, a lake at the head of the Columbia River *** Columbia Wetlands, a protected area near Columbia Lake ** Columbia Slough, along the Columbia watercourse near Portland, Oregon * Glacial Lake Columbia, a proglacial lake in Washington state * Columbia Icefield, in the Canadian Rockies * Columbia Island (District of Columbia), in the Potomac River * Columbia Island (New York), in Long Island Sound Populated places * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harvard University Alumni
The list of Harvard University people includes notable graduates, professors, and administrators affiliated with Harvard University. For a list of notable non-graduates of Harvard, see notable non-graduate alumni of Harvard. For a list of Harvard's presidents, see President of Harvard University. Eight President of the United States, Presidents of the United States have graduated from Harvard University: John Adams, John Quincy Adams, Rutherford B. Hayes, John F. Kennedy, Franklin Delano Roosevelt, Theodore Roosevelt, George W. Bush, and Barack Obama. Bush graduated from Harvard Business School, Hayes and Obama from Harvard Law School, and the others from Harvard College. Over 150 Nobel Prize winners have been associated with the university as alumni, researchers or faculty. Nobel laureates Pulitzer Prize winners ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Physical Chemists
American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, people who self-identify their ancestry as "American" ** American English, the set of varieties of the English language native to the United States ** Native Americans in the United States, indigenous peoples of the United States * American, something of, from, or related to the Americas, also known as "America" ** Indigenous peoples of the Americas * American (word), for analysis and history of the meanings in various contexts Organizations * American Airlines, U.S.-based airline headquartered in Fort Worth, Texas * American Athletic Conference, an American college athletic conference * American Recordings (record label), a record label previously known as Def American * American University, in Washington, D.C. Sports teams Soccer * Ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1894 Births
Events January–March * January 4 – A military alliance is established between the French Third Republic and the Russian Empire. * January 7 – William Kennedy Dickson receives a patent for motion picture film in the United States. * January 9 – New England Telephone and Telegraph installs the first battery-operated telephone switchboard, in Lexington, Massachusetts Lexington is a suburban town in Middlesex County, Massachusetts, United States. It is 10 miles (16 km) from Downtown Boston. The population was 34,454 as of the 2020 census. The area was originally inhabited by Native Americans, and was firs .... * February 12 ** French anarchist Émile Henry (anarchist), Émile Henry sets off a bomb in a Paris café, killing one person and wounding twenty. ** The barque ''Elisabeth Rickmers'' of Bremerhaven is wrecked at Haurvig, Denmark, but all crew and passengers are saved. * February 15 ** In Korea, peasant unrest erupts in the Donghak Peasant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUPAC
The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is a member of the International Science Council (ISC). IUPAC is registered in Zürich, Switzerland, and the administrative office, known as the "IUPAC Secretariat", is in Research Triangle Park, North Carolina, United States. This administrative office is headed by IUPAC's executive director, currently Lynn Soby. IUPAC was established in 1919 as the successor of the International Congress of Applied Chemistry for the advancement of chemistry. Its members, the National Adhering Organizations, can be national chemistry societies, national academies of sciences, or other bodies representing chemists. There are fifty-four National Adhering Organizations and three Associate National Adhering Organizations. IUPAC's Inter-divisional Committee on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Organic Chemistry
Physical organic chemistry, a term coined by Louis Hammett in 1940, refers to a discipline of organic chemistry that focuses on the relationship between chemical structures and reactivity, in particular, applying experimental tools of physical chemistry to the study of organic molecules. Specific focal points of study include the rates of organic reactions, the relative chemical stabilities of the starting materials, reactive intermediates, transition states, and products of chemical reactions, and non-covalent aspects of solvation and molecular interactions that influence chemical reactivity. Such studies provide theoretical and practical frameworks to understand how changes in structure in solution or solid-state contexts impact reaction mechanism and rate for each organic reaction of interest. Application Physical organic chemists use theoretical and experimental approaches work to understand these foundational problems in organic chemistry, including classical and statist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portland, Maine
Portland is the largest city in the U.S. state of Maine and the seat of Cumberland County. Portland's population was 68,408 in April 2020. The Greater Portland metropolitan area is home to over half a million people, the 104th-largest metropolitan area in the United States. Portland's economy relies mostly on the service sector and tourism. The Old Port is known for its nightlife and 19th-century architecture. Marine industry plays an important role in the city's economy, with an active waterfront that supports fishing and commercial shipping. The Port of Portland is the second-largest tonnage seaport in New England. The city seal depicts a phoenix rising from ashes, a reference to recovery from four devastating fires. Portland was named after the English Isle of Portland, Dorset. In turn, the city of Portland, Oregon was named after Portland, Maine. The word ''Portland'' is derived from the Old English word ''Portlanda'', which means "land surrounding a harbor". The Greater ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
