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Correction /chemist

Cours gratuits > Forum > Forum anglais: Questions sur l'anglais || En bas

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Correction /chemist
Message de k3400 posté le 05-02-2013 à 14:32:43 (S | E | F)
Bonjour,

Je sais que ce n'est pas forcément ce qui vous plait le plus, mais j'ai un texte à rendre, et j'aurais voulu que vous jetiez un coup d'oeil pour corriger les erreurs grammaticales, de conjugaison, et d'orthographe s'il vous plaît.
Merci pour vos réponses
.

Linus Pauling

Introduction : We would like to present you with Linus Pauling, who was an American chemist. He was one of the most influential chemists in history, and he was one of the founders of quantum chemistry and molecular biology. He has received 2 Nobel Prizes.
In the first part we will see his chemical works and in the second part, we will see his Biology works.

I)
He worked on the electronic structure of atoms and molecules with Oppenheimer to understand the nature of chemical bond. He invented the concept of hybridization of atomic orbitals, and the concept of electronegativity.
The hybrid orbitals it's the combination of different atomic orbitals to make a same number of orbitals which are all equivalents. It's used to describe the properties of the molecules and the unsaturated compounds, but explains too the tetravalency of the carbon atom.
The eletronegativity is based on the energy required to breaks bonds, and on dipole moments of molecules. He established a scale of electronegavity. The electronegativity difference explains the ionic and covalent bonds because the electrons will be more or less shared between atoms. It's explains the unsaturated compounds or the aromatic structures too. In the aromatic structures, there aren't a rapid interconversion between two structures but the electrons can move into the molecule : it's named "resonance".
He worked on the crystals structure thanks to x-ray during few years.
He received the Nobel Prize in chemistry in 1954 for his researches.

II)
Linus Pauling liked the biology too. He discovered the helical structure of hemoglobin and he demonstrated that the hemoglobin molecule changes structure when it gains or loses an oxygen atom.
He proposed a triple helical structure of ADN that was wrong because there are only two helix.
He studied enzyme reactions in the organism. He thought the Vitamins might treat a lot of health problems. So he invented the orthomolecular medicine which is based on this concept. Currently, it's theory is always in the course of study.


Conclusion :
To conclude, Linus Pauling worked a lot of subject. He was passionate about the science. He received too a Nobel Peace Prize because he fought against the nuclear weapons tests and attacks. He didn't want the war to resolve conflicts.
He worked too on the electrical car, but stopped because the batteries wasn't good enough developed.

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Modifié par lucile83 le 05-02-2013 15:02



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