Simplified Chemistry

Rutherford model of atom Rutherford observed that atom has all the positive charge concentrated in a very small central region called the nucleus and that nucleus is surrounded by negatively charged particles called electrons revolving in orbits. He proved that the force of attraction between electrons and nucleus was counter balanced by the centrifugal force acting on the revolving electron. …

ATOMS Law of constant composition: This states that “A chemical compound (if pure) always contains the same elements combined together in the same proportion by mass regardless of bow the compound is prepared or from where it is obtained”. Law of conservation of mass: This is defined as “In every chemical reaction, the total mass of the products is the …

جـدول الذائبـية Solubility Chart : من خلال جـدول الذائبـية يمكن التنبؤ ما إذا كان الملح أو المركب قابل للذوبان في الماء أم لا .   جـدول الذائبيـة Solubility Chart       بوسترات (لوحات) كيميائية بدقة عالية (أكثر من 25 لوحة) من تصميم الأستاذ أكرم أمير العلي   تطبيقات كيميائية من تصميم الأستاذ أكرم امير العلي متوفر للجوالات التي تعمل …

المونوميرات و البولوميرات (لوحـة قابلة للتنزيل)   بوسترات (لوحات) كيميائية بدقة عالية (أكثر من 25 لوحة) من تصميم الأستاذ أكرم أمير العلي   تطبيقات كيميائية من تصميم الأستاذ أكرم امير العلي متوفر للجوالات التي تعمل بنظام أندرويد android على سوق جوجل بلاي google play 1 – تطبيق ملصقات الجدول الدوري باللغة العربية : بطاقات تحتوي على معلومات شاملة و مختصرة …

 Symbol θ. The unique tempera­ture at which the attractions and repulsions of a polymer in a solution cancel each other. It is analogous to the Boyle temperature of a nonideal gas. A polymer solution at the Flory temperature is called a theta (θ) solu­tion. At the Flory temperature the virial coefficient B, associated with the excuded volume of the polymer, …

 A type of ionic crystal structure in which the cations have an expanded face-centered cubic arrangement with the anions occupy­ing both types of tetrahedral hole. The cations have a coordination number of 8 and the anions have a coordination number of 4. Examples of compounds with this structure are CaF2, BaCl2, and PbO2. The antifluorite structure is the op­posite arrangement, …

A benzodiazepine used medically in some countries as a powerful hypnotic, sedative, and muscle relaxant. It was marketed in the US under the trade name Rohyp­nol. Flunitrazepam has become notorious as a so-called ‘date rape’ drug. It is quickly eliminated from the body, difficult to detect, and causes amne­sia, so that victims cannot remember events that occur when under the …

A sequence of pulses used for spin-echo experi­ments in nuclear magnetic resonance (NMR) in which the initial pulse is 90° followed by a series of 180° pulses. A CPMG sequence is designed so that the spin echoes die away ex­ponentially with time. Spin-spin re­laxation occurs characterized by a time constant T2, which can be deter­mined from the decay signal.

A chemi­cal reaction in which two molecular beams are crossed; one beam is re­garded as the incident beam of gas and the other as the target gas. This technique enables a great deal of in­formation to be gained about the chemical reaction since the states of both the target and projectile mol­ecules can be controlled. The inci­dent beam is characterized …

Compounds with large three-dimensional molecular struc­tures containing ether chains linked by three-coordinate nitrogen atoms. Thus cryptands are macropolycyclic polyaza-polyethers. For example, the compound (2,2,2)-cryptand has three chains of the form -CH2CH2OCH2CH2OCH2CH2-. These chains are linked at each end by a nitrogen atom. Cryptands, like the *crown ethers, can form coordi­nation complexes with ions that can fit into the cavity formed …