Solid-phase reactant

You can also use simple collision theory to explain why increasing the surface area of a solid-phase reactant speeds up a reaction. With greater surface area, more collisions can occur. This explains why campfires are started with paper and small twigs, rather than logs. Figure 6.8 shows an example of the effect of surface area on collision rate. 

Figure 9.1 Illustration of some processes in which sorbed species behave differently from dissolved molecules of the same substance. (a) Dissolved species may participate directly in air-water exchange while sorbed species may settle with solids. (b) Dissolved species may react at different rates as compared with their sorbed counterparts due to differential access of other dissolved and solid-phase reactants. ...

The oxidation of the evaporated iron thin films after the action of NO at 527 K was established with the help of electron diffraction. In Figure 9.13a and b, the electron diffraction patterns of the solid phase reactant, Fe, and the product of the action of NO over Fe are reported [119]. 

FIGURE 9.13 Electron diffraction patterns of the solid-phase reactant and product of the reaction between NO and Fe (a) initial Fe thin film, and (b) thin film reacted with NO at 527 K. 

Solid phase reactant Liquid phase reactant Gas phase reactant Miscellaneous synthesis methods... 

Ceramic Powder Synthesis with Solid Phase Reactant... 

Although the above discussion does not constitute a rigorous verification of the model (21), the similarity of the simulations presented here to observed profiles of H2S, FeS and FeS2 in marine sediments indicates that the model may be of value in the study and interpretation of vertical patterns in sulfur diagenesis. Comprehensive multiparameter analyses of sediment profiles from a variety of sites will be required to validate the model. In this endeavor techniques will have to be devised to ascertain the molar surface areas of the various solid phase reactants. Eventually it may be possible to expand the model presented here to include processes in the aerobic zone so that the depth to the oxidized-reduced boundary can be predicted as well as the pH profile through this boundary. This achievement would constitute a truly compr ensive model. 

Table 4.6. Comparison of Gibbs free energy (AG for carbonic, formic and acetic acids (Al ° represents reduction in the volume of solid phase products when compared to solid phase reactants)...

A pyrite decomposition process is an instationary process since the solid phase reactant is being consumed under pyrite-oxidizing conditions causing changes in both reactive surface and mineral mass. Only in a fictitious system, in which the velocity of the depyritization front penetration by chance equals the surface erosion stationary conditions may be found. Diffusion under instationary conditions may be described by numerical solutions of the transport reaction equation considering Picks second law. Reactions can be integrated quite simply, if transport and reaction are decoupled in a... 

Increasing the surface area of a solid-phase reactant in a reaction between a solid and a liquid will enhance the rate of reaction. This is because the reaction takes place at the boundary between the two phases, that is, on the sohd surface. Commonly, the effect of increasing surface area in the reaction between calcium carbonate (marble chips) and hydrochloric acid (see equation, page 149) is used as an investigation. Other reactions also illustrate the same point. 

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