Heteroatom

3 Key excerpts on "Heteroatom"

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  eBook - ePub

  Water Quality Data

  Analysis and Interpretation

  • Arthur Hounslow(Author)
  • 2018(Publication Date)
  • CRC Press

    (Publisher)

  CHAPTER 7Organic Chemistry Nomenclature

  Introduction

  Organic compounds are composed primarily of variable numbers of carbon and hydrogen atoms, usually with smaller numbers of oxygen, nitrogen, sulfur, phosphorus, and halogen atoms—chlorine, fluorine, and bromine. Other elements may be incorporated in organic compounds to form organometallic compounds, but those will not be discussed here. Although specific references are generally not practical in this chapter, the text “Nomenclature of Organic Compounds” by Fletcher et al. (1974) was relied on extensively when nomenclature problems arose.

  The carbon atoms are joined to one another as chains, branched structures, or in rings. The carbon-carbon bonds may be single (sharing one electron pair), double (sharing two electron pairs), or triple (sharing three electron pairs). The most important ring structure, benzene, is one that consists of six carbon atoms and six hydrogen atoms in a planar ring. If a noncarbon atom replaces a carbon in a ring structure, the compound is called a heterocyclic compound. Most of the variation among organic compounds is caused by special groups of organic atoms attaching to the carbon atoms. They are called functional groups and contain at least one noncarbon atom. It is the presence of these groups that give organic compounds their unique properties. Organic compounds containing only carbon and hydrogen are called hydrocarbons. If they contain one or more halogen atoms they are called halogenated hydrocarbons. They may be divided into two groups, depending on whether the benzene ring is present or not. These are listed in Table 7.1 .

  Early Organic Chemistry

  The term organic chemistry was originally used to designate those substances of plant and animal origin thought to be more closely related to one another than to subsiances of mineral origin. It was known that organic substances form CO2 and H2

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  Science in Nursing and Health Care

  • Tony Farine, Mark A. Foss(Authors)
  • 2013(Publication Date)
  • Routledge

    (Publisher)

  In addition, developments in health care will provide opportunities that have not existed in the past. For example, drug prescribing is one area of practice that is no longer the preserve of the medical profession. Clearly, an understanding of basic chemistry is advantageous to anyone embarking on a study of drugs and pharmacology. Perhaps one day you will run your own clinic and prescribe drugs for patients under your care in much the same way that doctors do now. In the meantime, the following summary points and self-test questions may be of help.

  Summary points

    Matter exists in three states: gas, liquid and solid.

    An atom is the smallest particle of matter that can enter a chemical reaction.

    A substance that consists of atoms of only one kind is referred to as an element.

    A substance that consists of atoms of more than one kind chemically bonded together is referred to as a compound.

    Atoms are made of protons, neutrons and electrons.

    Ions result when atoms gain or lose electrons.

    Ionic bonds are formed when electrons are exchanged between atoms.

    Covalent bonds are formed when atoms share electrons.

    When atoms share electrons equally, a non-polar molecule is formed.

    When atoms share electrons unequally, a polar molecule is formed.

    Hydrogen bonds form between polar molecules.

    Chemical reactions may be described as combination, decomposition, displacement, partner exchange, reversible or redox.

    Catalysts are substances that increase the rate of chemical reactions.

    Enzymes are protein catalysts.

    Organic chemistry is the study of compounds that contain carbon.

    Organic molecules are either aliphatic or aromatic.

    Important hydrocarbons include alkanes, alkenes and alkynes.

    Other aliphatic compounds are alcohols, aldehydes, ketones, carboxylic acids and amines.

    Phenol is one example of an aromatic alcohol.

  Self-test questions

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  Food Science and the Culinary Arts

  • Mark Gibson(Author)
  • 2018(Publication Date)
  • Academic Press

    (Publisher)

  What this and later experiments highlighted was the fact that “organic” molecules could be handled, manipulated, and synthesized just as minerals and metals could. What also altered with these changes was the meaning of the concept of organic chemistry. That is to say, organic chemistry was no longer the study of “living” things but rather of those molecules or compounds that contain carbon atoms (Seager and Slabaugh, 2013 ; Boudreaux, 2013). In this new incarnation, it was understood that carbon atoms can be linked to each other and other elements that collectively account for the majority of chemistry's broad field. Many, if not most, organic compounds will also contain other elements like hydrogen and/or sometimes oxygen, nitrogen, sulfur, and phosphorus. There are exceptions too regarding those compounds created solely from carbon such as diamond and graphite and also carbon dioxide, salts such as carbonates and cyanides that incidentally are considered to be inorganic compounds—this is mainly for historical reasons (Owusu-Apenten, 2004). As this chapter unfolds, it will be shown that carbon atoms can, in their physical form, produce complex structures like long or branched chains and rings or chiral compounds and other complex 3-D shapes (Boudreaux, 2013). But first, look at some basic building blocks of all elements, molecules, compounds, etc. B.1 Atoms, Elements, Molecules, Compounds and Mixtures Forming the basic units of all matter are tiny particles called “atoms.” Each atom comprises a dense central nucleus composed of a mix of positively charged protons and neutral (no charge) neutrons. The nucleus is then surrounded by a cloud of electrons with a negative charge equal to the positive charge of the protons. As there are equal numbers of protons and electrons, all atoms start out with a neutral electric charge. All atomic nuclei contain one or more protons along with neutrons (Fig. B.1). Fig

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