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42-513: A domino effect is the cumulative effect produced when one event sets off a series of similar or related events, a form of chain reaction . The term is an analogy to a falling row of dominoes . It typically refers to a linked sequence of events where the time between successive events is relatively short. The term can be used literally (about a series of actual collisions) or metaphorically (about causal linkages within systems such as global finance or politics). The literal, mechanical domino effect

84-495: A mathematical model based on Markov chains . In 1913, the German chemist Max Bodenstein first put forth the idea of chemical chain reactions. If two molecules react, not only molecules of the final reaction products are formed, but also some unstable molecules which can further react with the parent molecules with a far larger probability than the initial reactants. (In the new reaction, further unstable molecules are formed besides

126-416: A prompt critical event, which may finally be energetic enough for a nuclear reactor meltdown or (in a bomb) a nuclear explosion. Another metaphor for a chain reaction is the domino effect , named after the act of domino toppling , where the simple action of toppling one domino leads to all dominoes eventually toppling, even if they are significantly larger. Numerous chain reactions can be represented by

168-408: A chain reaction at the level of the nucleus. He did not envision fission as one of these neutron-producing reactions, since this reaction was not known at the time. Experiments he proposed using beryllium and indium failed. Later, after fission was discovered in 1938, Szilárd immediately realized the possibility of using neutron-induced fission as the particular nuclear reaction necessary to create

210-466: A chain-reaction, so long as fission also produced neutrons. In 1939, with Enrico Fermi, Szilárd proved this neutron-multiplying reaction in uranium. In this reaction, a neutron plus a fissionable atom causes a fission resulting in a larger number of neutrons than the single one that was consumed in the initial reaction. Thus was born the practical nuclear chain reaction by the mechanism of neutron-induced nuclear fission. Specifically, if one or more of

252-489: A long chain of reaction steps forming HCl. In 1923, Danish and Dutch scientists J. A. Christiansen and Hendrik Anthony Kramers , in an analysis of the formation of polymers, pointed out that such a chain reaction need not start with a molecule excited by light, but could also start with two molecules colliding violently due to thermal energy as previously proposed for initiation of chemical reactions by van' t Hoff . Christiansen and Kramers also noted that if, in one link of

294-502: A new method for determining the order of a reaction using graphics and applied the laws of thermodynamics to chemical equilibria. He also introduced the modern concept of chemical affinity . In 1886, he showed a similarity between the behaviour of dilute solutions and gases. In 1887, he and German chemist Wilhelm Ostwald founded an influential scientific magazine named Zeitschrift für physikalische Chemie (" Journal of Physical Chemistry "). He worked on Svante Arrhenius 's theory of

336-568: A professor of chemistry, mineralogy , and geology at the University of Amsterdam for almost 18 years before eventually becoming the chairman of the chemistry department. In 1896, van 't Hoff moved to Germany, where he finished his career at the University of Berlin in 1911. In 1901, he received the first Nobel Prize in Chemistry for his work with solutions. His work showed that very dilute solutions follow mathematical laws that closely resemble

378-425: A state of higher entropy. For example, a system may not be able to reach a lower energy state by releasing energy into the environment, because it is hindered or prevented in some way from taking the path that will result in the energy release. If a reaction results in a small energy release making way for more energy releases in an expanding chain, then the system will typically collapse explosively until much or all of

420-433: A strong electric field causes them to gain energy, and when they impact other atoms, the energy causes release of new free electrons and ions (ionization), which fuels the same process. If this process happens faster than it is naturally quenched by ions recombining, the new ions multiply in successive cycles until the gas breaks down into a plasma and current flows freely in a discharge. Electron avalanches are essential to

462-468: Is exploited in Rube Goldberg machines . In chemistry, the principle applies to a domino reaction , in which one chemical reaction sets up the conditions necessary for a subsequent one that soon follows. In the realm of process safety , a domino-effect accident is an initial undesirable event triggering additional ones in related equipment or facilities, leading to a total incident effect more severe than

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504-401: Is one of the two main products. The product •CH 3 CO (g) of the previous step gives rise to carbon monoxide (CO), which is the second main product. The sum of the two propagation steps corresponds to the overall reaction CH 3 CHO (g) → CH 4 (g) + CO (g), catalyzed by a methyl radical •CH 3 . This reaction is the only source of ethane (minor product) and it is concluded to be

546-489: Is physical damage to the crystal). Certain devices, such as avalanche diodes , deliberately make use of the effect. Examples of chain reactions in living organisms include excitation of neurons in epilepsy and lipid peroxidation . In peroxidation, a lipid radical reacts with oxygen to form a peroxyl radical (L• + O 2 → LOO•). The peroxyl radical then oxidises another lipid, thus forming another lipid radical (LOO• + L–H → LOOH + L•). A chain reaction in glutamatergic synapses

588-467: Is the cause of synchronous discharge in some epileptic seizures. Jacobus Henricus van %27t Hoff Jacobus Henricus van 't Hoff Jr. ( Dutch: [vɑn (ə)t ˈɦɔf] ; 30 August 1852 – 1 March 1911) was a Dutch physical chemist . A highly influential theoretical chemist of his time, van 't Hoff was the first winner of the Nobel Prize in Chemistry . His pioneering work helped found

630-428: Is the mechanism of a Geiger counter and also the visualization possible with a spark chamber and other wire chambers . An avalanche breakdown process can happen in semiconductors, which in some ways conduct electricity analogously to a mildly ionized gas. Semiconductors rely on free electrons knocked out of the crystal by thermal vibration for conduction. Thus, unlike metals, semiconductors become better conductors

672-829: The British Chemical Society in London, the Royal Netherlands Academy of Arts and Sciences (1892), American Chemical Society (1898), the Académie des Sciences in Paris (1905), and the Netherlands Chemical Society (1908). Of his numerous distinctions, van 't Hoff regarded winning the first Nobel Prize in Chemistry as the culmination of his career. The following are named after him: On 14 May 2021, asteroid 34978 van 't Hoff , discovered by astronomers with

714-426: The University of Utrecht in 1874. In 1878, van 't Hoff married Johanna Francina Mees. They had two daughters, Johanna Francina (1880–1964) and Aleida Jacoba (1882–1971), and two sons, Jacobus Henricus van 't Hoff III (1883–1943) and Govert Jacob (1889–1918). Van 't Hoff died at the age of 58, on 1 March 1911, at Steglitz , near Berlin, of tuberculosis . Van 't Hoff earned his earliest reputation in

756-446: The dielectric breakdown process within gases. The process can culminate in corona discharges , streamers , leaders , or in a spark or continuous electric arc that completely bridges the gap. The process may extend huge sparks — streamers in lightning discharges propagate by formation of electron avalanches created in the high potential gradient ahead of the streamers' advancing tips. Once begun, avalanches are often intensified by

798-580: The Nobel Prize in 1956 with Sir Cyril Norman Hinshelwood , who independently developed many of the same quantitative concepts. The main types of steps in chain reaction are of the following types. The chain length is defined as the average number of times the propagation cycle is repeated, and equals the overall reaction rate divided by the initiation rate. Some chain reactions have complex rate equations with fractional order or mixed order kinetics. The reaction H 2 + Br 2 → 2 HBr proceeds by

840-635: The Veterinary School) and to proclaim in his ‘La chimie dans l’espace’ how, in his bold flight to the top of the chemical Parnassus, the atoms appeared to him to be arranged in cosmic space." However, by about 1880, support for van 't Hoff's theory by such important chemists as Johannes Wislicenus and Viktor Meyer brought recognition. In 1884, Van 't Hoff published his research on chemical kinetics, titled Études de Dynamique chimique ( "Studies in Chemical Dynamics" ), in which he described

882-444: The creation of photoelectrons as a result of ultraviolet radiation emitted by the excited medium's atoms in the aft-tip region. The extremely high temperature of the resulting plasma cracks the surrounding gas molecules and the free ions recombine to create new chemical compounds. The process can also be used to detect radiation that initiates the process, as the passage of a single particles can be amplified to large discharges. This

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924-544: The discipline is known today. The third of seven children, van 't Hoff was born in Rotterdam , Netherlands, 30 August 1852. His father was Jacobus Henricus van 't Hoff Sr., a physician, and his mother was Alida Kolff van 't Hoff. From a young age, he was interested in science and nature, and frequently took part in botanical excursions. In his early school years, he showed a strong interest in poetry and philosophy . He considered Lord Byron to be his idol. Against

966-683: The dissociation of electrolytes and in 1889 provided physical justification for the Arrhenius equation . In 1896, he became a professor at the Prussian Academy of Sciences in Berlin. His studies of the salt deposits at Stassfurt were an important contribution to Prussia's chemical industry. Van 't Hoff became a lecturer in chemistry and physics at the Veterinary College in Utrecht . He then worked as

1008-469: The field of organic chemistry . In 1874, he accounted for the phenomenon of optical activity by assuming that the chemical bonds between carbon atoms and their neighbors were directed towards the corners of a regular tetrahedron . This three-dimensional structure accounted for the isomers found in nature. He shares credit for this with the French chemist Joseph Le Bel , who independently came up with

1050-540: The following mechanism: As can be explained using the steady-state approximation , the thermal reaction has an initial rate of fractional order (3/2), and a complete rate equation with a two-term denominator ( mixed-order kinetics ). The pyrolysis (thermal decomposition) of acetaldehyde , CH 3 CHO (g) → CH 4 (g) + CO (g), proceeds via the Rice-Herzfeld mechanism: The methyl and CHO groups are free radicals . This reaction step provides methane , which

1092-421: The higher the temperature. This sets up conditions for the same type of positive feedback—heat from current flow causes temperature to rise, which increases charge carriers, lowering resistance, and causing more current to flow. This can continue to the point of complete breakdown of normal resistance at a semiconductor junction, and failure of the device (this may be temporary or permanent depending on whether there

1134-486: The laws describing the behavior of gases . In 1885, Van 't Hoff was appointed as a Member of the Royal Netherlands Academy of Arts and Sciences . In 1904, he was elected as a member to the American Philosophical Society . Other distinctions include honorary doctorates from Harvard and Yale (1901), Victoria University , the University of Manchester (1903), and University of Heidelberg (1908). He

1176-489: The main chain ending step. Although this mechanism explains the principal products, there are others that are formed in a minor degree, such as acetone (CH 3 COCH 3 ) and propanal (CH 3 CH 2 CHO). Applying the Steady State Approximation for the intermediate species CH 3 (g) and CH 3 CO(g), the rate law for the formation of methane and the order of reaction are found: The rate of formation of

1218-438: The modern theory of chemical affinity , chemical equilibrium , chemical kinetics , and chemical thermodynamics . In his 1874 pamphlet, Van 't Hoff formulated the theory of the tetrahedral carbon atom and laid the foundations of stereochemistry . In 1875, he predicted the correct structures of allenes and cumulenes as well as their axial chirality . He is also widely considered one of the founders of physical chemistry as

1260-473: The primary accident alone. The metaphorical usage implies that an outcome is inevitable or highly likely (as it has already started to happen) – a form of slippery slope argument. When this outcome is actually unlikely (the argument is fallacious ), it has also been called the domino fallacy . Chain reaction Chain reactions are one way that systems which are not in thermodynamic equilibrium can release energy or increase entropy in order to reach

1302-438: The produced neutrons themselves interact with other fissionable nuclei, and these also undergo fission, then there is a possibility that the macroscopic overall fission reaction will not stop, but continue throughout the reaction material. This is then a self-propagating and thus self-sustaining chain reaction. This is the principle for nuclear reactors and atomic bombs . Demonstration of a self-sustaining nuclear chain reaction

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1344-2126: The product methane is ( 1 ) . . . d [ CH 4 ] d t = k 2 [ CH 3 ] [ CH 3 CHO ] {\displaystyle (1)...{\frac {d{\ce {[CH4]}}}{dt}}=k_{2}{\ce {[CH3]}}{\ce {[CH3CHO]}}} For the intermediates ( 2 ) . . . d [ CH 3 ] d t = k 1 [ CH 3 CHO ] − k 2 [ CH 3 ] [ CH 3 CHO ] + k 3 [ CH 3 CO ] − 2 k 4 [ CH 3 ] 2 = 0 {\displaystyle (2)...{\frac {d{\ce {[CH_3]}}}{dt}}=k_{1}{\ce {[CH3CHO]}}-k_{2}{\ce {[CH3]}}{\ce {[CH3CHO]}}+k_{3}{\ce {[CH3CO]}}-2k_{4}{\ce {[CH3]}}^{2}=0} and ( 3 ) . . . d [ CH 3 CO ] d t = k 2 [ CH 3 ] [ CH 3 CHO ] − k 3 [ CH 3 CO ] = 0 {\displaystyle (3)...{\frac {d{\ce {[CH3CO]}}}{dt}}=k_{2}{\ce {[CH3]}}{\ce {[CH3CHO]}}-k_{3}{\ce {[CH3CO]}}=0} Adding (2) and (3), we obtain k 1 [ CH 3 CHO ] − 2 k 4 [ CH 3 ] 2 = 0 {\displaystyle k_{1}{\ce {[CH3CHO]}}-2k_{4}{\ce {[CH3]}}^{2}=0} so that ( 4 ) . . . [ CH 3 ] = k 1 2 k 4 [ CH 3 CHO ] 1 / 2 {\displaystyle (4)...{\ce {[CH3]}}={\frac {k_{1}}{2k_{4}}}{\ce {[CH3CHO]}}^{1/2}} Using (4) in (1) gives

1386-399: The rate law ( 5 ) d [ CH 4 ] d t = k 1 2 k 4 k 2 [ CH 3 CHO ] 3 / 2 {\displaystyle (5){\frac {d{\ce {[CH4]}}}{dt}}={\frac {k_{1}}{2k_{4}}}k_{2}{\ce {[CH3CHO]}}^{3/2}} , which is order 3/2 in

1428-649: The reactant CH 3 CHO. A nuclear chain reaction was proposed by Leo Szilard in 1933, shortly after the neutron was discovered, yet more than five years before nuclear fission was first discovered. Szilárd knew of chemical chain reactions, and he had been reading about an energy-producing nuclear reaction involving high-energy protons bombarding lithium, demonstrated by John Cockcroft and Ernest Walton , in 1932. Now, Szilárd proposed to use neutrons theoretically produced from certain nuclear reactions in lighter isotopes, to induce further reactions in light isotopes that produced more neutrons. This would in theory produce

1470-462: The reaction chain, two or more unstable molecules are produced, the reaction chain would branch and grow. The result is in fact an exponential growth, thus giving rise to explosive increases in reaction rates, and indeed to chemical explosions themselves. This was the first proposal for the mechanism of chemical explosions. A quantitative chain chemical reaction theory was created later on by Soviet physicist Nikolay Semyonov in 1934. Semyonov shared

1512-404: The same idea. Three months before his doctoral degree was awarded, van 't Hoff published this theory, which today is regarded as the foundation of stereochemistry , first in a Dutch pamphlet in the fall of 1874, and then in the following May in a small French book entitled La chimie dans l'espace . A German translation appeared in 1877, at a time when the only job van 't Hoff could find

1554-450: The stable products, and so on.) In 1918, Walther Nernst proposed that the photochemical reaction between hydrogen and chlorine is a chain reaction in order to explain what is known as the quantum yield phenomena. This means that one photon of light is responsible for the formation of as many as 10 molecules of the product HCl . Nernst suggested that the photon dissociates a Cl 2 molecule into two Cl atoms which each initiate

1596-423: The stored energy has been released. A macroscopic metaphor for chain reactions is thus a snowball causing a larger snowball until finally an avalanche results (" snowball effect "). This is a result of stored gravitational potential energy seeking a path of release over friction. Chemically, the equivalent to a snow avalanche is a spark causing a forest fire. In nuclear physics, a single stray neutron can result in

1638-661: The wishes of his father, van 't Hoff chose to study chemistry . First, he enrolled at Delft University of Technology in September 1869, and studied until 1871, when he passed his final exam on 8 July and obtained a degree of chemical technologist . He passed all his courses in two years, although the time assigned to study was three years. Then he enrolled at University of Leiden to study chemistry. He then studied in Bonn , Germany, with August Kekulé and in Paris with Adolphe Wurtz . He received his doctorate under Eduard Mulder at

1680-465: Was accomplished by Enrico Fermi and others, in the successful operation of Chicago Pile-1 , the first artificial nuclear reactor, in late 1942. An electron avalanche happens between two unconnected electrodes in a gas when an electric field exceeds a certain threshold. Random thermal collisions of gas atoms may result in a few free electrons and positively charged gas ions, in a process called impact ionization . Acceleration of these free electrons in

1722-519: Was at the Veterinary School in Utrecht. In these early years his theory was largely ignored by the scientific community, and was sharply criticized by one prominent chemist, Hermann Kolbe . Kolbe wrote: "A Dr. J. H. van 't Hoff of the Veterinary School at Utrecht has no liking, apparently, for exact chemical investigation. He has considered it more convenient to mount Pegasus (apparently borrowed from

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1764-746: Was awarded the Davy Medal of the Royal Society in 1893 (along with Le Bel ), and elected a Foreign Member of the Royal Society (ForMemRS) in 1897 . He was awarded the Helmholtz Medal of the Prussian Academy of Sciences (1911), and appointed Knight of the French Legion of Honour (1894) and Senator in the Kaiser-Wilhelm-Gesellschaft (1911). Van 't Hoff became an Honorary Member of

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