0.08206 L atm/K mol - Arizona State University
... Potential energy increases and kinetic energy increases. Potential energy increases and kinetic energy decreases. Potential energy decreases and kinetic energy increases. Potential energy decreases and kinetic energy decreases. There is no change at all. ...
... Potential energy increases and kinetic energy increases. Potential energy increases and kinetic energy decreases. Potential energy decreases and kinetic energy increases. Potential energy decreases and kinetic energy decreases. There is no change at all. ...
Hydrophobic Hydration
... bonds at the surface). For example, adding CH2 groups to aliphatic alcohols increases the heat produced on solution (ΔH/CH2 = -5.4 kJ mol-1) but causes a greater decrease in the entropy (TΔS/CH2 = +7.1 kJ mol-1) [1217]. The increased van der Waals attractions over the liquid gas interface causes γls ...
... bonds at the surface). For example, adding CH2 groups to aliphatic alcohols increases the heat produced on solution (ΔH/CH2 = -5.4 kJ mol-1) but causes a greater decrease in the entropy (TΔS/CH2 = +7.1 kJ mol-1) [1217]. The increased van der Waals attractions over the liquid gas interface causes γls ...
Organic Chemistry
... Note that although conformers can be referred to as stereoisomers, they are not stable isomers, since bonds in conformers can easily rotate thus converting one conformer to another which can be either diastereomeric or enantiomeric to the original one. While structural isomers typically have differe ...
... Note that although conformers can be referred to as stereoisomers, they are not stable isomers, since bonds in conformers can easily rotate thus converting one conformer to another which can be either diastereomeric or enantiomeric to the original one. While structural isomers typically have differe ...
Review of Thermodynamics
... interactions at the molecular level. One approach has been the use of simplified chemical ‘model’ compounds and this is one strand of supramolecular chemistry. What is Supramolecular Chemistry? Often defined as the chemistry of non-covalent interactions or literally “chemistry beyond the molecule” W ...
... interactions at the molecular level. One approach has been the use of simplified chemical ‘model’ compounds and this is one strand of supramolecular chemistry. What is Supramolecular Chemistry? Often defined as the chemistry of non-covalent interactions or literally “chemistry beyond the molecule” W ...
The crystal structure of L
... these sheets (i.e., within the chains that run along the b-axis and the ribbons that run along the a-axis), and stacking of the sheets along the c-axis involves only van der Waals interactions. In conclusion, we emphasize that the crystal structure of L-arginine reported here was determined directly ...
... these sheets (i.e., within the chains that run along the b-axis and the ribbons that run along the a-axis), and stacking of the sheets along the c-axis involves only van der Waals interactions. In conclusion, we emphasize that the crystal structure of L-arginine reported here was determined directly ...
Downloaded on 2017-02
... for reasons of computational expediency, the typical model has consisted of a single precursor molecule adsorbing onto a surface saturated with complementary fragments of the other precursor. Clearly, such a model of a single adsorbate is not designed to investigate a full layer of adsorbates satura ...
... for reasons of computational expediency, the typical model has consisted of a single precursor molecule adsorbing onto a surface saturated with complementary fragments of the other precursor. Clearly, such a model of a single adsorbate is not designed to investigate a full layer of adsorbates satura ...
Review 1
... made of silver but does not want it damaged during the analysis. The chemist decides to determine the density, knowing that silver has a density of 10.5 g/ml. The figurine is put into a graduated cylinder that contains 32.6 ml of water. The reading while the figurine is in the water is 60.1 ml. The ...
... made of silver but does not want it damaged during the analysis. The chemist decides to determine the density, knowing that silver has a density of 10.5 g/ml. The figurine is put into a graduated cylinder that contains 32.6 ml of water. The reading while the figurine is in the water is 60.1 ml. The ...
Slide 1 - nanoHUB
... • Often, nanoparticles (nanocrystals) do not form welldefined crystal facets. • The Wulff crystal shapes are idealized cases where the crystal surface energies determine the shape (thermodynamic control). • Kinetic factors often play a major role in crystal growth. This explains why different proces ...
... • Often, nanoparticles (nanocrystals) do not form welldefined crystal facets. • The Wulff crystal shapes are idealized cases where the crystal surface energies determine the shape (thermodynamic control). • Kinetic factors often play a major role in crystal growth. This explains why different proces ...
Self-assembled monolayer
Self-assembled monolayers (SAM) of organic molecules are molecular assemblies formed spontaneously on surfaces by adsorption and are organized into more or less large ordered domains. In some cases molecules that form the monolayer do not interact strongly with the substrate. This is the case for instance of the two-dimensional supramolecular networks of e.g. Perylene-tetracarboxylicacid-dianhydride (PTCDA) on gold or of e.g. porphyrins on highly oriented pyrolitic graphite (HOPG). In other cases the molecules possess a head group that has a strong affinity to the substrate and anchors the molecule to it. Such a SAM consisting of a head group, tail and functional end group is depicted in Figure 1. Common head groups include thiols, silanes, phosphonates, etc.SAMs are created by the chemisorption of ""head groups"" onto a substrate from either the vapor or liquid phase followed by a slow organization of ""tail groups"". Initially, at small molecular density on the surface, adsorbate molecules form either a disordered mass of molecules or form an ordered two-dimensional ""lying down phase"", and at higher molecular coverage, over a period of minutes to hours, begin to form three-dimensional crystalline or semicrystalline structures on the substrate surface. The ""head groups"" assemble together on the substrate, while the tail groups assemble far from the substrate. Areas of close-packed molecules nucleate and grow until the surface of the substrate is covered in a single monolayer.Adsorbate molecules adsorb readily because they lower the surface free-energy of the substrate and are stable due to the strong chemisorption of the ""head groups."" These bonds create monolayers that are more stable than the physisorbed bonds of Langmuir–Blodgett films. A Trichlorosilane based ""head group"", for example in a FDTS molecule reacts with an hydroxyl group on a substrate, and forms very stable, covalent bond [R-Si-O-substrate] with an energy of 452 kJ/mol. Thiol-metal bonds, that are on the order of 100 kJ/mol, making the bond a fairly stable in a variety of temperature, solvents, and potentials. The monolayer packs tightly due to van der Waals interactions, thereby reducing its own free energy. The adsorption can be described by the Langmuir adsorption isotherm if lateral interactions are neglected. If they cannot be neglected, the adsorption is better described by the Frumkin isotherm.