This abnormal electron density affects the applied magnetic field and causes the observed chemical shift to change.

He showed that, although matter can change its state in a chemical reaction, the total mass of matter is the same at the end as at the beginning of every chemical change.

Bistable chemical systems have been studied extensively to analyse relaxation kinetics, non-equilibrium thermodynamics, stochastic resonance, as well as climate change.

In a chemical reaction, chemical equilibrium is the state in which both reactants and products are present at concentrations which have no further tendency to change with time.

Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst.

In the catalyzed elementary reaction, catalysts do not change the extent of a reaction: they have no effect on the chemical equilibrium of a reaction because the rate of both the forward and the reverse reaction are both affected ( see also thermodynamics ).

This change in energy is called the change in internal energy of a chemical reaction.

Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants.

These rates depend on the concentration and therefore change with time of the reaction: the reverse rate gradually increases and becomes equal to the rate of the forward reaction, establishing the so-called chemical equilibrium.

The world ’ s first ice-calorimeter, used in the winter of 1782-83, by Antoine Lavoisier and Pierre-Simon Laplace, to determine the heat evolved in various chemical change s ; calculations which were based on Joseph Black ’ s prior discovery of latent heat.

While Proust believed that chemical compounds are composed of a fixed ratio of their constituent elements irrespective of the methods of production, Berthollet believed that this ratio can change according to the ratio of the reactants initially taken.

But, in fact, when I look at a person I see this maelstrom of organic, chemical and electron chaos ; volatility and instability, shimmering ; and the ability to change and transform and transmute.

Infrared EMR interacts with dipoles present in single molecules, which change as atoms vibrate at the ends of a single chemical bond.

In 1889, he showed how the characteristics of the current produced could be used to calculate the free energy change in the chemical reaction producing the current.

Chemically modified electrodes are electrodes that have their surfaces chemically modified to change the electrode's physical, chemical, electrochemical, optical, electrical, and transport properties.

An explosion is a type of spontaneous chemical reaction that, once initiated, is driven by both a large exothermic change ( great release of heat ) and a large positive entropy change ( great quantities of gases are released ) in going from reactants to products, thereby constituting a thermodynamically favorable process in addition to one that propagates very rapidly.

This means that the change in enthalpy under such conditions is the heat absorbed ( or released ) by a chemical reaction.

An enthalpy change describes the change in enthalpy observed in the constituents of a thermodynamic system when undergoing a transformation or chemical reaction.

Hence it is the atomic number alone that determines the chemical properties of an element ; and it is for this reason that an element can be defined as consisting of any mixture of atoms with a given atomic number.

Although the neutral ground-state chemical compounds of argon are presently limited to HArF, argon can form clathrates with water when atoms of it are trapped in a lattice of the water molecules.

He proposed that each element consists of atoms of a single, unique type, and that these atoms can join together to form chemical compounds.

A matrix can have a considerable effect on the way a chemical analysis is conducted and the quality of its results.

Its chemical and physical properties are so similar to that of natural amethyst that it can not be differentiated with absolute certainty without advanced gemnological testing ( which is often cost-prohibitive ).

Allotropes are different structural forms of the same element and can exhibit quite different physical properties and chemical behaviours.

Depression can be treated by increasing the amount of available serotonin, a chemical used in the brain to transmit signals between neurons.

Only a proper, artist-grade acrylic gesso should be used to prime canvas in preparation for painting with acrylic ( however acrylic paint can be applied to raw canvas if so desired without any negative effect or chemical reaction as would be the case with oils ).

This data can therefore image near atomically sharp interfaces with the associated chemical information.

These oxidants can damage cells by starting chemical chain reactions such as lipid peroxidation, or by oxidizing DNA or proteins.

Further, chemical biology employs biological systems to create non-natural hybrids between biomolecules and synthetic devices ( for example emptied viral capsids that can deliver gene therapy or drug molecules ).

In addition, many saccharide units can undergo various chemical modification, such as amination, and can even form parts of other molecules, such as glycoproteins.

Bistability can only arise in biological and chemical systems if three necessary conditions are fulfilled: positive feedback, a mechanism to filter out small stimuli and a mechanism to prevent explosions.

It can be symbolically depicted through a chemical equation, which usually involves atoms as subjects.

They can be analyzed using the tools of chemical analysis, e. g. spectroscopy and chromatography.

The atom is also the smallest entity that can be envisaged to retain the chemical properties of the element, such as electronegativity, ionization potential, preferred oxidation state ( s ), coordination number, and preferred types of bonds to form ( e. g., metallic, ionic, covalent ).

) the structure of polyatomic molecules, that are constituted of more than six atoms ( of several elements ) can be crucial for its chemical nature.

Cooking can also occur through chemical reactions without the presence of heat, most notably as in Ceviche, a traditional South American dish where fish is cooked with the acids in lemon or lime juice.

In this way or by substitution for the cemetitious and aggregate phases, the finished product can be tailored to its application with varying strength, density, or chemical and thermal resistance properties.

Several kinds of descriptive categorizations can be applied broadly to the elements, including consideration of their general physical and chemical properties, their states of matter under familiar conditions, their melting and boiling points, their densities, their crystal structures as solids, and their origins.

In chemical terms, calcium is reactive and soft for a metal ( though harder than lead, it can be cut with a knife with difficulty ).

Compounds of californium are dominated by a chemical form of the element, designated californium ( III ), that can participate in three chemical bonds.

The process in which the outcome of any one stage is known only statistically is also of interest, although for chemical reactor design it is not as important as the deterministic process.

Significantly, Huxley also worked for a time in the 1920s at the technologically advanced Brunner and Mond chemical plant in Billingham, Teesside, and the most recent introduction to his famous science fiction novel Brave New World ( 1932 ) states that this experience of " an ordered universe in a world of planless incoherence " was one source for the novel.

Alkanes ( also known as paraffins or saturated hydrocarbons ) are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds ( i. e., they are saturated compounds ) without any cycles ( or loops ; i. e., cyclic structure ).

In chemical terms, proline is, therefore, an imino acid, since it lacks a primary amino group, although it is still classed as an amino acid in the current biochemical nomenclature, and may also be called an " N-alkylated alpha-amino acid ".

Lavoisier also contributed to early ideas on composition and chemical changes by stating the radical theory, believing that radicals, which function as a single group in a chemical process, combine with oxygen in reactions.

He also introduced the possibility of allotropy in chemical elements when he discovered that diamond is a crystalline form of carbon.

Analytical chemistry is also focused on improvements in experimental design, chemometrics, and the creation of new measurement tools to provide better chemical information.

The late 20th century also saw an expansion of the application of analytical chemistry from somewhat academic chemical questions to forensic, environmental, industrial and medical questions, such as in histology.

A number of harmful and undesired ( adverse ) effects have been observed, including lowered life expectancy, extrapyramidal effects on motor control – including akathisia ( an inability to sit still ), trembling, and muscle weakness – weight gain, decrease in brain volume ( although this is being debated, since schizophrenia, which is often treated with antipsychotics, also causes a shrinkage of brain volume ), enlarged breasts ( gynecomastia ) in men and milk discharge in men and women ( galactorrhea due to hyperprolactinaemia ), lowered white blood cell count ( agranulocytosis ), involuntary repetitive body movements ( tardive dyskinesia ), diabetes, sexual dysfunction, a return of psychosis requiring increasing the dosage due to cells producing more neurochemicals to compensate for the drugs ( tardive psychosis ), and a potential for permanent chemical dependence leading to psychosis worse than before treatment began, if the drug dosage is ever lowered or stopped ( tardive dysphrenia ).

Plant potash lent the name to the element potassium, which was first derived from caustic potash, and also gave potassium its chemical symbol K ( cf German Kalium ), which ultimately derives from alkali.

The anoxic setting had been thought to not only protect the newly dead organisms from decay, but it also created chemical conditions allowing the preservation of the soft parts of the organisms.

This gradual transformation is an important consideration when studying the properties of elemental berkelium and its chemical compounds, since the formation of californium brings not only chemical contamination, but also self-radiation damage, and self-heating from the emitted alpha particles.

The role of the bacteria is the further oxidation of the ore, but also the regeneration of the chemical oxidant Fe < sup > 3 +</ sup > from Fe < sup > 2 +</ sup >.

Like some of the chemical weapons, biological weapons may also be useful as area denial weapons.

Though herbicides are chemicals, they are often grouped with biological warfare and chemical warfare because they may work in a similar manner as biotoxins or bioregulators and also because the Army Biological Laboratory tested them and the Army's Technical Escort Unit which all chemical, biological, radiological ( nuclear ) materials.

Translucent Bakelite jewelry, poker chips and other gaming items such as chess sets were also introduced in the 1940s under the Prystal Corporation name, however, its basic chemical composition remained the same.

Biotechnology draws on the pure biological sciences ( genetics, microbiology, animal cell culture, molecular biology, biochemistry, embryology, cell biology ) and in many instances it is also dependent on knowledge and methods from outside the sphere of biology ( chemical engineering, bioprocess engineering, information technology, biorobotics ).

The Swiss chemical industry operates largely from Basel, and Basel also has a large pharmaceutical industry.

Nonhuman communication also include cell signaling, cellular communication, and chemical transmissions between primitive organisms like bacteria and within the plant and fungal kingdoms.

Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties.

The mole is a unit of measurement that denotes an amount of substance ( also called chemical amount ).