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Chapitre 2
Tableau périodique et éléments organiques
Elements are the smallest units of matter that cannot be broken down further by chemical processes. There are 118 known elements, but not all of…
Structure atomique
All matter is composed of atoms, the smallest individual units of elements. Each atom is made up of three subatomic particles: protons, neutrons,…
Comportement des électrons
Electrons are negatively charged subatomic particles that are attracted to an orbit around the positively-charged nucleus of an atom. They reside…
Modèle orbital électronique
Orbitals are the areas outside of the atomic nucleus where electrons are most likely to reside. They are characterized by different energy levels,…
Molécules et composés
An atom is most stable when its valence shell—the outermost energy shell that contains electrons—is full. Most elements do not…
Formes moléculaires
The shape of a molecule contributes to its function and its interactions with other molecules. Over the years, many different models have been…
Squelettes de carbone
The backbone of all organic compounds is a carbon skeleton. Each carbon atom can make four bonds, and as the carbon skeleton increases in length,…
Réactions chimiques
A chemical reaction is a process by which the bonds in the atoms of substances are rearranged to generate new substances. Matter cannot be created…
Isotopes
Elements have a set number of protons that determines their atomic number. For example, all atoms with eight protons are oxygen. However, the number…
Liaisons covalentes
When two atoms share electrons to complete their valence shells they create a covalent bond. An atom’s electronegativity—the force with…
Liaisons ioniques
When atoms gain or lose electrons to achieve a more stable electron configuration they form ions. Ionic bonds are electrostatic attractions between…
Liaisons hydrogènes
Hydrogen bonds are weak attractions between atoms that have formed other chemical bonds. One of these atoms is electronegative, like oxygen, and has…
Interactions de Van der Waals
Van der Waal interactions are nonspecific attractions created when one atom comes close enough to another one to disturb its electrons—inducing…
États de l'eau
Water exists in three main states: solid (ice), liquid, and gas (steam). The state water is in depends on the intermolecular forces that draw water…
pH
The potential for a solution to donate or accept hydrogen ions determines whether it is an acid or a base. Acidic solutions donate protons, whereas…
Solvants
A solvent is a substance, most often a liquid, that can dissolve other substances. Here, the substance being dissolved is called a solute. When a…
Réactions redox
Oxidation-reduction, or redox, reactions change the oxidation states of atoms via the transfer of electrons from one atom, the reducing agent, to…
Adhésion
Adhesion occurs when one type of molecule is attracted to a different kind of molecule. Water exhibits adhesive properties in the presence of polar…
Cohésion
Cohesion is the attraction between molecules of the same type - such as water molecules. The partially charged negative oxygen of one water molecule…
Chaleur spécifique
A substance’s specific heat capacity refers to the amount of energy required to heat one gram of the substance by one degree. Water has a high…
Vaporisation
Vaporization changes a liquid substance into a gaseous or vaporous substance. To achieve this, kinetic energy must be greater than the intermolecular…
Differential Effects of Lipid-lowering Drugs in Modulating Morphology of Cholesterol Particles
Treatment of dyslipidemia patients with lipid-lowering drugs leads to a significant reduction in low-density lipoproteins (LDL) level and a low to…
Cholesterol Efflux Assay
Cholesterol content of cells must be maintained within the very tight limits, too much or too little cholesterol in a cell results in disruption of…
Biochemical and High Throughput Microscopic Assessment of Fat Mass in <em>Caenorhabditis Elegans</em>
The nematode C. elegans has emerged as an important model for the study of conserved genetic pathways regulating fat metabolism as it relates to…

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