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                  Referring to the study of the structure of matter called a philosopher

"Compared to philosophy - is math, compared with mathematics is philosophy."

                Scientific theories are, indeed, on the border between concrete and abstract of mathematics cold - trying to fit in formulas and equations all that exists around us and even ourselves - and philosophy, sometimes devoid of realism, a Universe too complex to be explained and whose understanding, if it were possible, it would only disturb her existence, if not empty of meaning to it.
               It is true that in the universe there is lowest'' ', also just as there is no "greatest." Just do it persivitate the frontier as interesting operation "microcosm" as that of "macrocosm ".
              We will always be looking for the smallest particles in the structure of matter, as in the search for the most distant galaxies.

            It is obvious that scientific theories are not "closed". Their development is a historical character, being, in turn, enriched
 and - if emphasizing the shortcomings of too deep - even abandoned, thus illustrating processuality scientific knowledge.
           As is known, initially thought that matter is continued, then denied its continuity and introduced the famous "atomistic hypothesis". It was considered that the substance is made of "atoms" are regarded as indivisible, as attested by the name they have received.
          Later it turned out that atoms have internal structure, the
consisting of electronic shell and core. Moreover, he, in turn, is composed of nucleons - protons and neutrons.
         At present, researchers are convinced that no nucleons are the smallest particles that make up matter. Constituent nucleons have been called "quarks" (quarks), but is not sufficiently substantiated their theory on The experienced.
       It remains the task of future generations to unequivocally prove the existence of quarks (and possibly find their inner existence).
      In the last decades, science and technology - chemistry in particular have experienced unprecedented growth with the advent of computers and software solvers with great precision equations whose solutions would have been so impossible to find, and at the same time to provide a intiutiva, accessible our understanding of abstract notions, starting with those of "atomic orbitals", "equipotential surfaces", "nodal surfaces" through to computer modeling of the structure of atomic structure - giant type ( cluster) or different types of recipes that allow, among others, viewing normal modes of vibration characteristic of such polyatomic systems and even identify their symmetry.
       Despite the real explosion of information that we have today thanks to new technologies and access to computer equipment, and even if at the beginning of a new millennium, the old basic concepts of chemistry - the far outweighed came not to be scientifically satisfactory to decipher literature of our time, they remain a primer on the knowledge, whose assimilation is necessary, if only moral cosiderente NIM, because modern chemistry learning, not to live in a house without foundations.

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Simbol chimic : N
Masa atomica : 14
Numar de masa “Z”: 7
Azotul se gaseste in grupa a V-a principala ai in prima perioada in sistemul periodic.
Azotul este un caz incolor, inodor, insipid si non-toxic. El poate fi condensat intr-un lichid incolor si apoi compresat intr-un solid incolor si cristalin.
Nitrogenul are denistatea cu putin mai mica decat a aerului si este mai putin solubil in apa decat oxigenul. El nu intretine viata fiintelor care il respira.
Temperatura de topire a azotului este de – 210, 01 °C , in timp ce cea de fierbere este de – 195, 79 °C.
STARE NATURALA: Azotul este unul dintre gazele extrem de raspandite in natura. El se gaseste atat in stare libera cat si sub forma de compusi:
In stare libera, azotul reprezinta 78% din volumul aerului atmosferic.
Compusii azotului sunt:
-anorganici ( amoniac, azotati, etc. )
-organici (uree, proteine )
Azotul de gaseste intr-o proportie de la 1 la 10 % in fiecare din organismele vii.



Proprietăţi fizice

În funcţie de masa lor molară, alcanii sunt gazoşi, lichizi sau solizi.
Datorită diferenţei mici de electronegativitate dintre atomii de carbon şi hidrogen, alcanii conţin numai legături covalente nepolare. De aceea între moleculele alcanilor se exercită forţe de atracţie van der Waals.
Cu cât molecula este mai mare cu atât energia necesară pentru ruperea forţelor intermoleculare trebuie să fie mai mare, iar punctele de fierbere corespunzătoare vor creşte.

ALCANI C1-C4 C5- C17 C18, C19,…. Stare de agregare ( 25º C) GAZE LICHIDE SOLIDE Puncte de fierbere Cresc cu creşterea masei molare Densităţi ( ρalcani < 1 Cresc cu creşterea masei molare

Dintre izomerii de catenă ai unui alcan, cel cu catenă normală are punctul de fierbere cel mai ridicat, iar izoalcanul cel mai ramificat are punctul de fierbere cel mai scăzut.


Abuzul de droguri II

· Astazi în toata lumea sunt în jurul 190 milioane utilizatori de drogurilor.
· Utilizarea drogurilor sporeste în rândul tinerilor din lume. Majoritatea utilizatorilor au vârsta sub 30 de ani.
· În 1999, numarul tarilor care raporteaza utilizarea drogurilor prin injectare a fost de 136, numarul fiind de 80 în 1992. Dintre acestea, 93 de tari de asemenea identifica HIV printre injectatorii de droguri.
· Cannabis este cel mai utilizat drog în toate partile lumii.
· Costul economic total al abuzului de droguri în Statele Unite se estimeaza aproximativ la 70 miliarde dolari anual.
· Abuzul de cocaina printre somerii din Columbia este de 10 ori mai mare decât printre persoanele angajate.
· Industria drogurilor clandestina se estimeaza la 400 miliarde dolari pe an.

Abuzul de DROGURI
Abuzul de droguri inseamna orice utilizare excesiva, continua ori sporadica, incompatibila sau în relatie cu practica medicala, a unui drog. Consumul poate fi exceptional, în scopul de a înce…