ALBUM OF ENGLISH
Members: Luisanna Molina Luisana Villasmil Vidalia Chavarria Anthony Rivero
ANALOQUES OF HIDROCARBONDS Hydrocarbons are organic compounds composed solely of carbon and hydrogen atoms. Molecular structure consisting of a skeleton of carbon atoms that bind to hydrogen atoms. Hydrocarbons are the basic compounds of organic chemistry. Chains of carbon atoms can be straight or branched and open or closed. Those having in the molecule other chemical elements (hetero) substituted hydrocarbons are known. Hydrocarbons may be classified into two types, which are aliphatic and aromatic. Aliphatics, in turn can be classified into alkanes, alkenes and alkynes by the types of link linking together the carbon atoms. The general formulas of alkanes, alkenes and alkynes are CnH2n +2, CnH2n and CnH2n-2, respectively.
According to the type of structures that can form, hydrocarbons can be classified as:Acyclic hydrocarbons, which have their open strings. In turn are classified as:Linear Hydrocarbons those without side chains (branches). Branched hydrocarbons, which have side chains. Cycloalkanes or cyclic hydrocarbons, which are defined as closed chain hydrocarbons. These again are categorized as: Monocyclic having one operation cyclization. Polycyclic, containing several cyclization operations.
CHEMICAL BONDING A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electrostatic force of attraction between opposite charges, either between electrons and nuclei, or as the result of a dipole attraction. The strength of chemical bonds varies considerably; there are "strong bonds" such as covalent or ionic bonds and "weak bonds" such as dipole窶電ipole interactions, the London dispersion force and hydrogen bonding. Since opposite charges attract via a simple electromagnetic force, the negatively charged electrons that are orbiting the nucleus and the positively charged protons in the nucleus attract each other.
An electron positioned between two nuclei will be attracted to both of them, and the nuclei will be attracted toward electrons in this position. This attraction constitutes the chemical bond. Due to the matter wave nature of electrons and their smaller mass, they must occupy a much larger amount of volume compared with the nuclei, and this volume occupied by the electrons keeps the atomic nuclei relatively far apart, as compared with the size of the nuclei themselves. This phenomenon limits the distance between nuclei and atoms in a bond. In general, strong chemical bonding is associated with the sharing or transfer of electrons between the participating atoms. The atoms in molecules, crystals, metals and diatomic gasesâ€” indeed most of the physical environment around usâ€” are held together by chemical bonds, which dictate the structure and the bulk properties of matter.
ORGANIC NOMENCLATURE Naming Organic Compounds: The increasingly large number of organic compounds identified with each passing day, together with the fact that many of these compounds are isomers of other compounds, requires that a systematic nomenclature system be developed. Just as each distinct compound has a unique molecular structure which can be designated by a structural formula, each compound must be given a characteristic and unique name. As organic chemistry grew and developed, many compounds were given trivial names, which are now commonly used and recognized. Some examples are: Name Methane Butane Acetone Toluene Acetylene Ethyl Alcohol Formula CH4 C4H10 CH3COCH3 CH3C6H5 C2H2 C2H5OH
Such common names often have their origin in the history of the science and the natural sources of specific compounds, but the relationship of these names to each other is arbitrary, and no rational or systematic principles underly their assignments. The IUPAC Systematic Approach to Nomenclature: A rational nomenclature system should do at least two things. First, it should indicate how the carbon atoms of a given compound are bonded together in a characteristic lattice of chains and rings. Second, it should identify and locate any functional groups present in the compound. Since hydrogen is such a common component of organic compounds, its amount and locations can be assumed from the tetravalency of carbon, and need not be specified in most cases.
The IUPAC nomenclature system is a set of logical rules devised and used by organic chemists to circumvent problems caused by arbitrary nomenclature. Knowing these rules and given a structural formula, one should be able to write a unique name for every distinct compound. Likewise, given a IUPAC name, one should be able to write a structural formula. In general, an IUPAC name will have three essential features: • A root or base indicating a major chain or ring of carbon atoms found in the molecular structure. • A suffix or other element(s) designating functional groups that may be present in the compound. • Names of substituent groups, other than hydrogen, that complete the molecular structure. As an introduction to the IUPAC nomenclature system, we shall first consider compounds that have no specific functional groups. Such compounds are composed only of carbon and hydrogen atoms bonded together by sigma bonds (all carbons are sp3 hybridized).
RADIOISOTOPE TRACERS A radioactive tracer, or radioactive label, is a chemical compound in which one or more atoms have been replaced by a radioisotope so by virtue of its radioactive decay it can be used to explore the mechanism of chemical reactions by tracing the path that the radioisotope follows from reactants to products. Radioisotopes of hydrogen, carbon, phosphorus, sulphur, and iodine have been used extensively to trace the path of biochemical reactions. A radioactive tracer can also be used to track the distribution of a substance within a natural system such as a cell or tissue. Radioactive tracers are also used to determine the location of fractures created by hydraulic fracturing in natural gas production.
Radioactive tracers form the basis of a variety of imaging systems, such as, PET scans, SPECT scans and technetium scans. Isotopes of a chemical element differ only in the mass number. For example, the isotopes of hydrogen can be written as 1H, 2H and 3H, with the mass number at top left. When the atomic nucleus of an isotope is unstable, compounds containing this isotope are radioactive. Tritium is an example of a radioactive isotope.
THE CHEMICAL INDUSTRY The chemical industry comprises the companies that produce industrial chemicals. Central to the modern world economy, it converts raw materials (oil, natural gas, air, water, metals, and minerals) into more than 70,000 different products.
NUCLEAR ENERGY usually means the part of the energy of an atomic nucleus, which can be released by fusion or fission or radioactive decay. is the use of exothermic nuclear processes, to generate useful heat and electricity. The term includes nuclear fission, nuclear decay and nuclear fusion. Presently the nuclear fission of elements in the actinide series of the periodic table produce the vast majority of nuclear energy in the direct service of humankind, with nuclear decay processes, primarily in the form of geothermal energy, and radioisotope thermoelectric generators, in niche uses making up the rest. Nuclear (fission) power stations, excluding the contribution from naval nuclear fission reactors, provided about 5.7% of the world's energy and 13% of the world's electricity in 2012. In 2013, the IAEA report that there are 437 operational nuclear power reactors, in 31 countries, although not every reactor is producing electricity.
In addition, there are approximately 140 naval vessels using nuclear propulsion in operation, powered by some 180 reactorsAs of 2013, attaining a net energy gain from sustained nuclear fusion reactions, excluding natural fusion power sources such as the Sun, remains an ongoing area of international physics and engineering research. More than 60 years after the first attempts, commercial fusion power production remains unlikely before 2050.
Published on Feb 5, 2014