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Full-Text Articles in Physical Sciences and Mathematics
Cdse Quantum Dot Surface Chemistry Thermodynamics Via Isothermal Titration Calorimetry: An Emphasis On The Fundamentals, Megan Y. Gee
Cdse Quantum Dot Surface Chemistry Thermodynamics Via Isothermal Titration Calorimetry: An Emphasis On The Fundamentals, Megan Y. Gee
Theses and Dissertations
For several decades, the study and development of colloidal semiconductor nanocrystals, or quantum dots (QD), has become a rich field heralding improved integration into applications ranging from photovoltaics and photocatalysis to biomedical imaging and drug delivery. CdxSey is the most extensively studied QD system, however numerous compositional details still confound the nanocrystal field. Although CdSe QDs with native ligand coatings can show high fluorescence quantum yield and may be suitable for some applications, often times these original ligand layers are comprised of long aliphatic chains that preclude incorporation into biological matrices or severely impede charge transfer – depending on the …
I. An Isothermal Titration Microcalorimeter. Ii. Importance Of Micronutrients In Nutrition. Iii. Zinc Bibliography, John Willard Gardner
I. An Isothermal Titration Microcalorimeter. Ii. Importance Of Micronutrients In Nutrition. Iii. Zinc Bibliography, John Willard Gardner
Theses and Dissertations
I. An isothermal titration microcalorimeter having a colume of 4 ml and capable of temerature control to ±2 x 10-5°C is described. Major components include a constant temperature water bath controlled to ±3 x 10-4°C, a platinum reation vessel, and an isothermal control circuit consisting of constant Peltier thermoelectric cooling and variable Joule heating controlled by a thermistor in an AC Wheatstone bridge circuit. The calorimeter was tested by measuring the heat of ionization of water and was found to produce data accurate to ± 0.1% where small samples are used such as in the investigation of many biological systems.
|Ni.|Pa Calorimetric Study Of The Heat Of Ionization Of Water At 10 And 40°C, And,|Nii.|Pa Calorimetric Determination Of The Heat Of Reaction Of Tris (Hydroxymethyl) Aminomethane (Tham) With Hydrochloric Acid In Aqueous Solution At 10, 25, And 40°C, Griffith Lyn Kimball
Theses and Dissertations
The heat of neutralization, ΔH_-N, of perchloric acid with sodium hydroxide has been determined at 10 and 40° in a low ionic strength, μ, region using a nonisothermal, constant-temperature-environment solution calorimeter. Correction of the data to infinite dilution by extrapolation of a plot of ΔH_-N vs μ^0.5 gives values at zero ionic strength for the heat of ionization of water of 14.216 and 12.695 kcal/mole, respectively, at 10 and 40° . The data are correlated with those of earlier workers to give an equation allowing the calculation of the heat of ionization of water at zero ionic strength over the …
A Calorimetric Study Of Metal Ion Cyclic Polyether Interaction :|Bi. Cation Binding Properties Of Macrocyclic Polyethers In Aqueous Solution As A Function Of Temperature ; Ii. Effect Of Solvent Dielectric Constant On The Binding Properties Of Cyclic Polyethers For Na[Superscript +] And K[Superscript +], Dennis Pershing Nelson
Theses and Dissertations
The complexation properties of the two isomers of the cyclic polyether dicyclohexyl-18-crown-6 are examined in aqueous solution for a series of metal ions at various reaction temperatures. The results are discussed in terms of size relationships and salvation characteristics of both polyether and metal ions. ΔCp° values are determined from the temperature dependence of the ΔH° values. A discussion of the errors involved in the determination of ΔH° from the temperature dependence of log K values is also included. Comparisons are made between the results of this study and those of a similar study by H. K. Frensdorff, E. I. …
Thermodynamics Of Proton Ionization In Aqueous Solution I. A Precision Thermometric Titration Calorimeter ; Ii. Entropy Titration : A Calorimetric Method For Equilibrium Constant Determinations ; Iii. H And S Values For Carboxylic Acid Proton Ionization At 25c ; Iv. Site Of Proton Ionization From Adenosine, Lee D. Hansen
Theses and Dissertations
The design, construction, and calibration of a precision thermometric titration calorimeter is described. This calorimeter was tested by determining the enthalpy change for ionization of water. The result, 13.34 ±0.03 kcal/mole (standard deviation), is in exact agreement with the best literature values. This standard deviation indicates that, using this calorimeter, ΔH values can be determined with an accuracy of ±0.0.5 kcal/mole. A calorimetric procedure has been developed for the, simultaneous determination of the equilibrium constant, the enthalpy change, and the entropy change for a chemical reaction from a single titration (Entropy Titration). This procedure has been tested by determining pK, …
A Calorimetric Study Of Metal Amino Acid Complexes In Aqueous Solution. I. The Copper (Ii) Glycine System. Ii. The Nickel (Ii) Glycine, Alanine And Phenylalanine Systems, Wilbur Orme Greenhalgh
A Calorimetric Study Of Metal Amino Acid Complexes In Aqueous Solution. I. The Copper (Ii) Glycine System. Ii. The Nickel (Ii) Glycine, Alanine And Phenylalanine Systems, Wilbur Orme Greenhalgh
Theses and Dissertations
Calorimeter values were obtained for the standard enthalpy change for the following reactions at 10,25, and 40 degrees C.: 1. The dissaciation of the amino acid, glycine, in the zwitterion form (HA) to give the basic form (A-) and a proton. 2. The reactions of copper (II) ion with glycine to form the Cu gly+ and Cu (gly)2 complexes. 3. The reactions of nickel (II) ion with glycine and alanine to form Ni gly+, Ni (gly)2, Ni al+, and Ni (al)2 complexes. For calorimetric enthalpy calculations, the initial and final concentrations of all species in the calorimeter must be known; …
Thermodynamics Of I) Metal Cyanide Coordination, Ii) Water Formation, And Iii) Metal Halide Coordination, John Dewey Hale
Thermodynamics Of I) Metal Cyanide Coordination, Ii) Water Formation, And Iii) Metal Halide Coordination, John Dewey Hale
Theses and Dissertations
ΔH values for the formation of Ni(CN)4(aq)= have been determined calorimetrically at 25° using a simple calorimeter and a thermometric titration procedure at high and low ionic strengths, respectively. Extrapolation of these ΔH values to infinite dilution resulted in a ΔH° value of -42.7 kcal./mole. Combination of ΔH° and ΔF° values gives a ΔS° value of -5.5 e.u. for Ni(CN)4(aq)= formation. A value of +70 e.u. is calculated for the ionic entropy of Ni(CN)4(aq)=. A preliminary investigation of the Zn(CN)4(aq)= system indicated the existence of zinc cyanide complexes other than Zn(CN)4= and allowed calculation of an approximate ΔH° value of …
Application Of The Quasi-Lattice Theory To The Heats Of Mixing Of Some Alcohol-Hydrocarbon Systems, Mar Lynn James
Application Of The Quasi-Lattice Theory To The Heats Of Mixing Of Some Alcohol-Hydrocarbon Systems, Mar Lynn James
Theses and Dissertations
Values for the heats of mixing were obtained calorimetrically for the systems C2H5OH-C6H12, CH3OH-C6H6 and C2H5OH-C6H6 at 25° over the complete range of composition. Analytical equations which summarize these values are: Benzene (1) - Methanol (2) System ΔHxM = x1x2[628.4 + 365.7(x1-x2) + 521.9(x1-x2)3 + 819.8(x1-x2)4 ] Benzene (1) - Ethanol (2) System ΔHxM = x1x2[748.8 + 534.1(x1-x2) + 265.7(x1-x2)2 + 408.7(x1-x2)3 + 434.1(x1-x2)4 ] Cyclohexane (1) - Ethanol (2) System ΔHxM = x1x2[615.0 + 132.4(x1-x2) + 195.9(x1-x2)2 + 251.5(x1-x2)3 + 521.7(x1-x2)4 ] where xi is the mole fraction of component i. The experimental data were satisfactorily interpreted by a …