Thermodynamic Systems and Spontaneity? | Yahoo Answers
Received Date: Apr 30, / Accepted Date: Jun 17, / Published Date: Jun 19 Entropy and Enthalpy values were also changed in mixed solvent systems. Keywords: Thermodynamic parameters; Calcium hydroxide; Mixed solvents; . in these mixed solvent systems followed non-spontaneous dissolution process in. Thermodynamics is the study of the inter-relation between heat, work and This along with other results of spontaneous urbanization demanded of a closed system equals the heat added to the system minus the work done by the system). *Corresponding Author Email: [email protected] Tel. data were well represented by the Freundlich isotherm model for all tested adsorption systems. Besides, the thermodynamic study has showed that the dye adsorption phenomenon onto P. oceanica biomass was favourable, endothermic and spontaneous.
These parameters state the physiochemical properties of a chemical system. Previously, many techniques have been applied to find the solubility products of various systems.
thermodynamic system and spontaneity? | Yahoo Answers
These techniques include spectral studies, viscosity, refractive index and some electro-analytical method like conductometry, potentiometry, polarography and voltametry etc. Most of the researchers aimed to infer data of very precise solubility product of these systems that are extremely less soluble or nearly insoluble in aqueous systems [ 8 - 10 ]. Method of very precise evaluation of Ksp values of various types of reagents having structural dissimilarities are reported [ 11 ].
- Thermodynamic system and spontaneity?
- What is a simple defintion of the laws of thermodynamics?
Clark also suggested a method to evaluate solubility product constant for various compounds along with a practical aspect pertaining to the problems associated with the determination of such compounds [ 12 ]. Different properties such as solubility, Ksp, Gibbs free energy, entropy and enthalpy associated with sparingly soluble salts are influenced with different parameters, such as change in percentage of solvent, amount of salts and temperature etc.
Thermodynamic Systems and Spontaneity?
In the present research work, pH metric method was used for the study of the influence of mixed solvent system on the solubility Ksp, Gibbs free energy, entropy and enthalpy of Ca OH 2. When a sparingly soluble compound like Ca OH 2 is added into water, equilibrium is established between the solid and aqueous material that can be approximately represented by the equation [ 13 ].
In previous work conductometric method was used for determination of thermodynamic parameters in mixed solvent systems [ 17 ]. But in present work pH metric method has been used. Experimental In the present research work, pH —metric method was used for the study of the influence of mixed solvent system on the solubility of Ca OH 2.
All reagents were used such as Ca OH 2 E. Merck1-Propanol E. Merck2-propanol E. Merckmethanol E. Merckethanol E.
MerckHydrochloric acid E. MerckOxalic acid E. MerckSodium hydroxide E. MerckPhenolphalein E. Merck and Buffer solutions E. Merck each of these analytical grade reagents. These stock solutions were prepared in double distilled water. Consequently, adsorption techniques seem to have the most potential for future use in industrial wastewater treatment Babel and Opiso, because of their proven efficiency in the removal of organic and mineral pollutants and for economic considerations Robinson, et al.
The most widely used adsorbent for this purpose is activated carbon, but its overlying coast McKay, et al. The main objective of the present study was to develop a low cost and efficient wastewater treatment technology by studying the capacities of a marine lignocellulosic material, Posidonia oceanica leaf sheaths for adsorptive removal of a reactive textile dye: The kinetic and equilibrium data of sorption studies were processed to understand the sorption mechanism of the dye molecule onto P.
Two kind of chemical treatments were then performed: A Ciba Geigi textile Azo dye has been experimented in this study: Reactive Red R. Batch adsorption experiments Adsorption experimentswere carried outby agitating 5 g of PLS with mL of dye solution for the desired concentration and pHinahorizontal shaker at rpm for the time required to reach the equilibrium state 48 h. Dye concentration was estimated spectrophotometrically atthe wavelengthcorresponding to maximum absorbance, nm, using a CamSpecM spectrophotometer.
The samples were taken from the shaker at predetermined time intervals and the dye solution was filtered through a 0. Each experiment was performed twice at least under identical conditions.
This effect is shown in Fig. The increase in the equilibrium sorption capacity of the R. Red dye, for the two concentrations investigated, indicates that a high temperature favours dye removal. Consequently, it is clear that adsorption equilibrium is a thermo-dependent process. This effect may be due to the fact that at higher temperatures, an increase in the movement of the solute occurs. Similar results are mentioned by other researchers Chakraborty, et al.
Effect of pH solution The initial pH value of the solution is an important factor which must be considered during sorption studies Aksu, The effect of pH on the amount of dye removal was analyzed over the pH range from 2 to 10 and the results are presented in Fig.
As shown, the maximum biosorption capacity was reached at pH 5 with 1. This trend might be explained by the fact that we deal with an Azo-based reactive dye combining different types of reactive groups. The pH 5 might correspond to the rate of dissociation of this dye with maximum ionisation of the molecule. Furthermore, in such pH, the PLS combines both negatively and positively charged cells surface, which enhance the electrostatic attraction between anionic and cationic species of both sorbate and adsorbate.
Moreover, inhibition of the dye sorption onto raw PLS at low acidic and high basic pH ranges may be attributed to the increase of hydroxyl and hydrogen ions leading to formation of aqua complexes thereby retarding the dye sorption Mohan, et al. Effect of chemical pre-treatment Fig. In the case of PLS treated with acidic solutions, it seems that the negative charges on the hydrolysed R. Therefore, such results suggest that the present biosorption phenomenon might be via a chemiosorption mechanism.
In other hand, the increase of the dye uptake using bleached PLS is probably due to the hydrolysis of the natural pigments mainly phycoxanthines which are chemically similar to synthetic dyes, generating therefore new active sorptive sites.
The enhancement of the dye adsorption capacity through chemical treatment of the biomass was also reported by Inthorn, et al. Sorption kinetic modelling For evaluating the adsorption kinetics of R. The first order equation is: Kad h-1 is the rate constant of first order model.
From the slopes and intercepts of plots of log qe-q versus t obtained for the biosorption of R. The correlation coefficients for the first-order kinetic model obtained at all studied PLS were low, except for the raw biomass with However, in the same, the theoretical qecal did not give acceptable values even for the raw PLS.
If necessity were the mother of all innovation, then the Industrial Revolution would be the mother of all necessities. Horrible living conditions in the overcrowded industrial cities bred a plethora of diseases and viruses. This along with other results of spontaneous urbanization demanded science again to address the problems of an ever-changing human civilization.
Science of the Industrial Age responded to such needs by centering on medical advances in the early stages of the revolution.
What is a simple defintion of the laws of thermodynamics?
Such was the era of crucial medical breakthroughs, and age of greatest physiologists - such as Marie Curie radiumWilhelm Roentgen x-raysLouis Pasteur pasteurizationEdward Jenner smallpox vaccinationJoseph Lister bacteria antisepticand Charles Darwin evolution.
Once the medical crisis was rectified, science could concentrate on the heart of an industrial society - large-scaled machinery. True of nineteenth century mass industry, the company with the greatest machines produced more products, made more money, and was consequently more successful.
It is natural, therefore, that fierce competition arose to find the most industrious machinery possible, and how far the limits of these machines could be pushed as to achieve maximum productivity without consuming much energy.
Again, society would fuel scientific advancement. Nineteenth century scientists were encouraged to study the machine, and its efficiency. To do this, physicists analyzed the flow of heat in these machines, and the chemical changes that transpire when they perform work. Thus was the establishment of modern thermodynamics. First on the agenda of this new discipline was to find a means convert heat as produced by machines into work with full efficiency. However, as the research was completed, the results were all but pleasing to the sponsors.Lec 5 Thermodynamics - Types of Thermodynamic systems - Animation video
As it turned out, the very same research oriented to create a perpetual-motion machine proved that the very concept is not possible. The proof lies in two theories now three that are currently considered the most important laws in the whole body of science - the First and Second Laws of Thermodynamics.
The First Law of Thermodynamics is really a prelude to the second. It states that the total energy output as that produced by a machine is equal to the amount of heat supplied. Generally, energy can neither be created nor destroyed, so the sum of mass and energy is always conserved. By its nature, this finding did not restrict the use of perpetual-motion machines.
However, the next law would deal a blow to all believers of such a wonder machine. The first law, a bellwether in the frontier pastures of Thermodynamics, contained one major flaw that rendered it inaccurate as it stood. This law is based on a conceptual reality, one that does not take into consideration limits placed by transactions occurring in the real world.
In other words, the first law failed to recognize that not all circumstances that conserve energy actually ensue naturally.