Oleh: adiriyadhi | 27 Maret 2008

GLOBAL WARMING
Global warming is perhaps the most important environmental problem in the world today. Levels of greenhouse gases are increasing in the atmosphere due to human activities, and are changing the composition of the atmosphere and global warming. Climate scientists agree that human activities such as the burning of fossil fuels contribute to the problem. Scientists have predicted the phenomemon of global warming for decades. Unfortunately, some of the adverse effects of global warming, they have also predicted begin to occur throughout the world, including: growing incidence of droughts in some areas, floods in others;
• The rising temperatures of oceans and the sea level;
• increase extreme weather events such as tornadoes and hurricanes;
• The melting of mountain glaciers and the reduction of snow cover;
• Dying coral reefs, and
• Coastal erosion, and loss of coastal ecosystems.
(Riska Haryati)

LIPID
Lipid is all compound produced by organism, do not in water of, but earning diekstraksi by pelarut able to dissolving like fat and example: chloroform, heksana, toluen, acetone. Lipid of most found in combination with compound other simple (like wax;candle ester, trigliserida, sterile of and ester fosfolipid), combination with carbohydrate (glikolipid), combination with protein (lipoprotein). Triterpenoid is the born of isoprenoid asiklik skualen (C30H50), intact component from cod, oil vegetable, mushroom .(Diyah Rauhillah Hasni)

CALORIMETRY
Calorimetry is a methode analysis chemistry of basic the similiary colour betwen lateness sampel of lateness standard. The eye detector usually use in calorimetry and to make sure for the consentration sampel in similiary standard lateness colour. The condition of the lateness must be colouring if not, the lateness must be given colour. (Eka Agustian)

PRECIPITATION
Precipitation is the formation of a solid in a solution during a chemical reaction.When the reaction occurs, the solid formed is called the precipitate, and the liquid remaining above the solid is called the supernate. Precipitation reactions can be used for making pigments, removing salts from water in water treatment, and for qualitative chemical analysis. (Rieda Rasyidah)

POLARIZABILITY
Polarizability is the ease of distortion of the electron cloud of a molecular entity by an electric field (such as that due to the proximity of a charged reagent). It is experimentally measured as the ratio of induced dipole moment to the field E which induces it : α = µ ind/E. The units of α are C2 m2 V-1. in ordinary usage the term refers to the “mean polarizability”, the average over three rectilinear axes of the molecule. Polarizabilities in different directions (e.g. along the bond in C12, called “longitudinal polarizability”, and in the direction perpendicular to the bond, called “transverse polarizability”) can be distinguished, at least in principle. Polarizability along the bond joining a substituent to the rest of the molecule is seen in certain modern theoretical approaches as a factor influencing chemical reactivity, etc. and parametrization there of has been proposed. (Nur Cholifah)

A Hydrogen Bond
A hydrogen bond is a special type of dipole-dipole force that exist between electronegative atom and a hydrogen atom bonded to another electronegative atom. This type of force always involves a hydrogen atom and the energy of this attraction is close to that of weak covalent bonds (155 kJ/mol), thus the name – Hydrogen Bonding. These attraction can occur between molecules (intermolecularly), or within different parts of a single molecule (intramolecularly). The hydrogen bond is a very strong fixed dipole-dipole van der Waals-Keesom force, but weaker than covalent, ionic, and metallic bonds. The hydrogen bond is somewhere between a covalent bond and an electrostatic intermolecular attraction. Intermolecular hydrogen bonding is responsible for the high boiling point of water (100 ºC). This is because of the strong hydrogen bond, as opposed to other group 16 hydrides. Intermolecular hydrogen bonding is partly responsible for the secondary, tertiary, and quaternary structures of proteins and nucleic acid. (Nur Cholifah).


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