THE DIFFUSION MECHANISM OF HYDROCARBONS IN... Jirong Xiao B.S., East China Institute of Chemical Technology
... interactions and the molecule-molecule interactions on these properties are probed. Thie molecule-zeolite interactions dominantly determine the orders of magnitude of the diffusivity, whereas te molecule-molecule interactions could alter the concentration dependence of the diffusivity. The mode of t ...
... interactions and the molecule-molecule interactions on these properties are probed. Thie molecule-zeolite interactions dominantly determine the orders of magnitude of the diffusivity, whereas te molecule-molecule interactions could alter the concentration dependence of the diffusivity. The mode of t ...
Electrochemical and Spectroelectrochemical Studies of Dyes used
... At present, human world energy use is made up mainly of fossil fuels (gas, coal and oil), hydroelectricity, nuclear power and tiny fractions from biomass and other solar energy sources. Fossil fuels are causing environment pollution and becoming gradually exhausted. Nuclear energy obtained from nucl ...
... At present, human world energy use is made up mainly of fossil fuels (gas, coal and oil), hydroelectricity, nuclear power and tiny fractions from biomass and other solar energy sources. Fossil fuels are causing environment pollution and becoming gradually exhausted. Nuclear energy obtained from nucl ...
Introduction and literature survey
... and vitamins. Many complex amines have pronounced physiological activity, for example, epinephrine (adrenaline), thiamine or vitamin B1 and Novocaine. The odour of decaying fish is due to simple amines produced by bacterial action. Amines are used to manufacture many medicinal chemicals such as sulf ...
... and vitamins. Many complex amines have pronounced physiological activity, for example, epinephrine (adrenaline), thiamine or vitamin B1 and Novocaine. The odour of decaying fish is due to simple amines produced by bacterial action. Amines are used to manufacture many medicinal chemicals such as sulf ...
Chemical Force Spectroscopy in Heterogeneous Systems
... molecularly smooth probe and sample areas has been studied with the surface force apparatus19,20 but provides data averaged over a macroscopic area (∼1 mm2). Measurements of the noncontact forces due to van der Waals,21,22 acid-base,23 and electrostatic interactions24-27 between a micrometer size pr ...
... molecularly smooth probe and sample areas has been studied with the surface force apparatus19,20 but provides data averaged over a macroscopic area (∼1 mm2). Measurements of the noncontact forces due to van der Waals,21,22 acid-base,23 and electrostatic interactions24-27 between a micrometer size pr ...
Sructural and chemisorption properties of metallic surfaces and metallic overlayers
... electronic structure at a coverage of 2.5 ML. No evidence of CO chemisorption on the Pd films of less than 2.5 ML coverage is observed, while thicker film readily chemisorb CO. In the study of Ni on W(110), it is observed that the initial growth of Ni occurs in a double-layer mode, which is very dif ...
... electronic structure at a coverage of 2.5 ML. No evidence of CO chemisorption on the Pd films of less than 2.5 ML coverage is observed, while thicker film readily chemisorb CO. In the study of Ni on W(110), it is observed that the initial growth of Ni occurs in a double-layer mode, which is very dif ...
Date: 16 / 01 / 2014 - Qatar University QSpace
... series of experiments were carried out to study the variation of preparation parameters such as support type, temperature, ‘ion-exchange’ time and the concentration of the (precursor) salt. ...
... series of experiments were carried out to study the variation of preparation parameters such as support type, temperature, ‘ion-exchange’ time and the concentration of the (precursor) salt. ...
A Straightforward Route to Enantiopure Pyrrolizidines and
... The reduction behavior of the catalysts The reduction behavior of the AC-supported Mo-based catalysts was studied by means of TPR technique, and has been reported elsewhere in detail [55]. Results are briefly presented and discussed below, with special emphasis being on the relationship between thes ...
... The reduction behavior of the catalysts The reduction behavior of the AC-supported Mo-based catalysts was studied by means of TPR technique, and has been reported elsewhere in detail [55]. Results are briefly presented and discussed below, with special emphasis being on the relationship between thes ...
hydrogen storage
... recombine to form molecules inside the tube and arrange themselves in a concentric pattern. The hydrogen pressure inside the SWNT increases with the number of injected atoms and reaches 35 GPa for 90 atoms (5 mass%). This simulation does not show condensation of hydrogen inside the nanotube. The cri ...
... recombine to form molecules inside the tube and arrange themselves in a concentric pattern. The hydrogen pressure inside the SWNT increases with the number of injected atoms and reaches 35 GPa for 90 atoms (5 mass%). This simulation does not show condensation of hydrogen inside the nanotube. The cri ...
Sulfur and iron surface states on fractured pyrite surfaces
... Pyrite has a poor {001} cleavage. Unlike most other minerals with a rocksalt-type structure, pyrite typically fractures conchoidally, demonstrating that parting surfaces are not constrained to the {001} crystallographic plane. Cleavage along {001} require rupture of only Fe-S bonds, but pyrite consi ...
... Pyrite has a poor {001} cleavage. Unlike most other minerals with a rocksalt-type structure, pyrite typically fractures conchoidally, demonstrating that parting surfaces are not constrained to the {001} crystallographic plane. Cleavage along {001} require rupture of only Fe-S bonds, but pyrite consi ...
Ch. 11-12 Supplements
... each. a. H2O2 b. N2O4 c. C12H22O11 d. P2O5 e. C2H5OH f. C8H18 2) C2H3O is the empirical formula for a compound. List three possible molecular formulas. 3) A 20-gram sample of unknown is found to contain 12.4 g carbon, 2.06 g hydrogen, and 5.52 g oxygen. a. What is the empirical formula for this comp ...
... each. a. H2O2 b. N2O4 c. C12H22O11 d. P2O5 e. C2H5OH f. C8H18 2) C2H3O is the empirical formula for a compound. List three possible molecular formulas. 3) A 20-gram sample of unknown is found to contain 12.4 g carbon, 2.06 g hydrogen, and 5.52 g oxygen. a. What is the empirical formula for this comp ...
Lecture Notes in Physical Chemistry Semester 2: Kinetics and
... (Notice that the exponent on the normalization factor is now 3/2.) If you think of the function d N v x v y v z /N as living in a three-dimensional “velocity space” whose axes are v x , v y , and v z , then the dv x dv y dv z part of Eq. (1.31) describes the volume of a small rectangular box, which ...
... (Notice that the exponent on the normalization factor is now 3/2.) If you think of the function d N v x v y v z /N as living in a three-dimensional “velocity space” whose axes are v x , v y , and v z , then the dv x dv y dv z part of Eq. (1.31) describes the volume of a small rectangular box, which ...
Intermolecular forces and molecules
... boiling point. Do electronegativity differences account for this difference? Due to the molecule geometry, the bond dipoles in each cancel. In this case, differences in molar mass (polarizability) account for the variation in boiling point. Having noted that molar mass affects van der Waals forces, ...
... boiling point. Do electronegativity differences account for this difference? Due to the molecule geometry, the bond dipoles in each cancel. In this case, differences in molar mass (polarizability) account for the variation in boiling point. Having noted that molar mass affects van der Waals forces, ...
Adsorption
Adsorption is the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved solid to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. This process differs from absorption, in which a fluid (the absorbate) permeates or is dissolved by a liquid or solid (the absorbent). Adsorption is a surface-based process while absorption involves the whole volume of the material. The term sorption encompasses both processes, while desorption is the reverse of it. Adsorption is a surface phenomenon.Similar to surface tension, adsorption is a consequence of surface energy. In a bulk material, all the bonding requirements (be they ionic, covalent, or metallic) of the constituent atoms of the material are filled by other atoms in the material. However, atoms on the surface of the adsorbent are not wholly surrounded by other adsorbent atoms and therefore can attract adsorbates. The exact nature of the bonding depends on the details of the species involved, but the adsorption process is generally classified as physisorption (characteristic of weak van der Waals forces) or chemisorption (characteristic of covalent bonding). It may also occur due to electrostatic attraction.Adsorption is present in many natural, physical, biological, and chemical systems, and is widely used in industrial applications such as activated charcoal, capturing and using waste heat to provide cold water for air conditioning and other process requirements (adsorption chillers), synthetic resins, increase storage capacity of carbide-derived carbons, and water purification. Adsorption, ion exchange, and chromatography are sorption processes in which certain adsorbates are selectively transferred from the fluid phase to the surface of insoluble, rigid particles suspended in a vessel or packed in a column. Pharmaceutical industry applications, which use adsorption as a means to prolong neurological exposure to specific drugs or parts thereof, are lesser known.However, it should be remarked that the distinction between adsorption and absorption vanishes as we go from perfectly crystalline macroscopic materials to porous/structured materials, aggregates and composites made out of increasingly smaller grains, viz., micron-sized particles to nanoparticles, sub-nano particles and finally molecules (or atoms). In such nano-composites, the internal surface area of particulate matter is very large. Then the adsorption on internal surfaces simply becomes absorption when viewed from the bulk. Then the distinction between adsorption and absorption vanishes. On the other hand, the distinction is clearest between bulk solids without internal structure, but having only surfaces where only adsorption can occur on the outer surfaces, and nanocomposites or aggregates with internal structure where absorption by the host material is simply adsorption on internal surfaces of the host material. As an example, we may consider a crystalline piece of silicon dioxide (quartz) which can adsorb water molecules on its surface. However, if the quartz is ground into very fine sand, the pile of sand (an aggregate) has a very large internal surface area. A very large amount of water can be adsorbed by the ""internal"" surfaces of the grains in the pile of sand, and this absorption is simply ""internal adsorption. If water is made to flow thorugh such a pile of sand, ions and toxins in the water may be preferentially adsorbed by the surfaces of the grains of sand, providing a simple, well-known water purification application.The word ""adsorption"" was coined in 1881 by German physicist Heinrich Kayser (1853-1940).