Whether this abnormal TSH differs chemically from pituitary TSH, or is, alternatively, normal TSH with its period of effectiveness modified by some other blood constituent, cannot be decided without chemical study of the activity in the blood of these patients and a comparison of the substance responsible for the blood activity with pituitary Aj.

This text clarified the concept of an element as a substance that could not be broken down by any known method of chemical analysis, and presented Lavoisier's theory of the formation of chemical compounds from elements.

Oxidation is a chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent.

The type of chemical reactions a substance may undergo and the energy changes that may accompany it are constrained by certain basic rules, known as chemical laws.

The concept of chemical element is related to that of chemical substance.

A chemical element is specifically a substance which is composed of a single type of atom.

A compound is a substance with a particular ratio of atoms of particular chemical elements which determines its composition, and a particular organization which determines its chemical properties.

Strictly speaking, a mixture of compounds, elements or compounds and elements is not a chemical substance, but it may be called a chemical.

In this scheme each chemical substance is identifiable by a number known as its CAS registry number.

A molecule is the smallest indivisible portion of a pure chemical substance that has its unique set of chemical properties, that is, its potential to undergo a certain set of chemical reactions with other substances.

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

According to Brønsted – Lowry acid-base theory, acids are substances that donate a positive hydrogen ion to another substance in a chemical reaction ; by extension, a base is the substance which receives that hydrogen ion.

Chemists carefully measure substance proportions, reaction rates, and other chemical properties.

Muhammad ibn Zakariya ar-Razi ( Rhazes ), the Persian chemist and most famous alchemist, the inventor of alcohol, isolated many chemical substance s, produced many medication s, and described many laboratory apparatus.

A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus.

The drug's chemical name is listed, since most states require feed processors to use this name instead of the trade name on the feed tag.

In some instances, the trade name is shown in parentheses following the chemical name.

Even here there is room for some variation, for metal surfaces vary in smoothness, absorptive capacity, and chemical reactivity.

As is well known, detergent actives belong to the chemical class consisting of moderately high molecular weight and highly polar molecules which exhibit the property of forming micelles in solution.

On chemical grounds it seems most likely that iodide is first converted to Af and then to Af as the active iodinating species.

The chemical nature of the iodocompounds is discussed below ( pp. 76 et seq. ).

It is therefore necessary to consider the properties of pituitary TSH if the fragmentary chemical information about blood TSH is to be discussed rationally.

The importance of knowing in what chemical forms the hormone may exist is accentuated by the recent observation that there exists an abnormally long-acting TSH in blood drawn from many thyrotoxic patients ( Adams, 1958 ).

The aim is to collect a very broad range of physical, chemical, morphological, and structural data for crystals on an encyclopedic scale and to seek all possible useful and revealing correlations of properties with internal structure.

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.

It is a popular belief that alchemists made contributions to the " chemical " industries of the day — ore testing and refining, metalworking, production of gunpowder, ink, dyes, paints, cosmetics, leather tanning, ceramics, glass manufacture, preparation of extracts, liquors, and so on ( it seems that the preparation of aqua vitae, the " water of life ", was a fairly popular " experiment " among European alchemists ).

Experiments have been conducted to attempt the synthesis of ununennium ( Uue ), which is likely to be the next member of the group, but they have all met with failure .< ref name =" link "> However, ununennium may not be an alkali metal due to relativistic effects, which are predicted to have a large influence on the chemical properties of superheavy elements.

Each element has a specific set of chemical properties as a consequence of the number of electrons present in the neutral atom, which is Z ( the atomic number ).

The number of electrons in each element's electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior.

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.

Argon ( ) is a chemical element with symbol Ar and atomic number 18.

The name " argon " is derived from the Greek word αργον meaning " lazy " or " the inactive one ", a reference to the fact that the element undergoes almost no chemical reactions.

Arsenic ( ) is a chemical element with symbol As and atomic number 33.

Antimony ( or ; ) is a toxic chemical element with symbol Sb and atomic number 51.

Actinium ( ) is a radioactive chemical element with symbol Ac and atomic number 89, which was discovered in 1899.

For substances which have two ( or more ) stable crystalline forms, such as diamond and graphite for carbon, there is a kind of " chemical degeneracy ".

Benzodiazepines share a similar chemical structure, and their effects in humans are mainly produced by the allosteric modification of a specific kind of neurotransmitter receptor, the GABA < sub > A </ sub > receptor, which increases the conductance of this inhibitory channel ; this results in the various therapeutic effects as well as adverse effects of benzodiazepines.

The term concentration can be applied to any kind of chemical mixture, but most frequently it refers to solutes in solutions.

This kind of cell includes the Galvanic cell or Voltaic cell, named after Luigi Galvani and Alessandro Volta, both scientists who conducted several experiments on chemical reactions and electric current during the late 18th century.

Ultimately, a chemical park emerged at nearby Leuna which is one of the most modern sites of its kind in Europe with high ecological standards.

On the scale of the single Kurdish village of Halabja within its own territory, Iraqi forces did expose the populace to some kind of chemical weapons, possibly mustard gas and most likely nerve agents.

Another set of important questions in chemistry concerns what kind of reactions can happen spontaneously and which properties are possible for a given chemical mixture.

This kind of approach was used by Whorf when he attributed the occurrence of fires at a chemical plant to the workers ' use of the word ' empty ' to describe the barrels containing only explosive vapors.

In any chemical reaction, not only is the total mass conserved but also the numbers of atoms of each kind are conserved, and this imposes corresponding constraints on possible values for the stoichiometric coefficients.

He also studied qualitative analysis, and conducted chemical experiments on the train until an accident prohibited further work of the kind.

In this kind of thermal rocket, the nuclear reactor's energy replaces the chemical energy of the propellant's reactive chemicals in a chemical rocket.

In the leisure thus gained he wished to " recruit his spirits, range his papers ", and prepare some important chemical investigations which he proposed to leave " as a kind of Hermetic legacy to the studious disciples of that art ", but of which he did not make known the nature.

Chemisorption is a kind of adsorption which involves a chemical reaction between the surface and the absorbate.

The other meaning of chemical synthesis is narrow and restricted to a specific kind of chemical reaction, a direct combination reaction, in which two or more reactants combine to form a single product.

IBT was an industrial product safety testing laboratory that was used by pharmaceutical companies, chemical manufacturers and other industrial clients, operated one of the largest facility of its kind in the US, and performed more than one-third of all toxicology testing in the United States.

* Mixture, a kind of chemical substance

The chemical composition of nodules varies according to the kind of manganese minerals and the size and characteristics of the core.

Azeotropes can be considered as a kind of mixture which usually pose considerable difficulties regarding the separation processes required to obtain their constituents ( physical or chemical processes or, even a blend of them ).

During the investigation, it becomes apparent that certain innocent chemicals can be combined into a strong depressor, a kind of chemical weapon.

* Photostationary state, the equilibrium chemical composition under a specific kind of electromagnetic irradiation

In parallel, the city underwent numerous changes in landscape, including the completion of the A1 freeway, the first road of its kind, during the 1960s, and the acceleration of industrialization with a focus on the chemical and automotive industries.

* Without the need for receptors to recognize chemical messengers, signal transmission at electrical synapses is more rapid than that which occurs across chemical synapses, the predominant kind of junctions between neurons.