Electrical conductivity of fused lead bromide + potassium bromide mixtures

1973 ◽  
Vol 26 (4) ◽  
pp. 739 ◽  
Author(s):  
EA Jeffery ◽  
T Mole
Keyword(s):  
Electrical Conductivity ◽  
Initial Rate ◽  
Potassium Bromide ◽  
Methyl Groups ◽  
Alternative Mechanism ◽  
Lead Bromide ◽  
Kinetics Of ◽  
Monomer Pair

Bridge-terminal exchange of methyl groups in trimethylaluminium dimer and the exchange of methyl groups between the dimer and trimethylgallium or dimethylzinc are all interpreted as proceeding by initial rate-determining dissociation of the trimethyl-aluminium dimer to liquid-caged monomer pair. Most exchange occurs before the monomers of the pair become separated. An alternative mechanism in which exchange follows separation is rejected. ��� The choice of mechanism is based on (a) p.m.r. kinetics of exchange between trimethylgallium and trimethylaluminium in cyclopentane; (b) p.m.r. kinetics of exchange between dimethylzinc and trimethylaluminium in cyclopentane; and (c) estimates of the rate of recombination of trimethylaluminium monomer.

scholarly journals Thermodynamic and detailed kinetic study of the formation of orthophthalaldehyde-agmatine complex by fluorescence intensities

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Khémesse Kital ◽  
Moumouny Traoré ◽  
Diégane Sarr ◽  
Moussa Mbaye ◽  
Mame Diabou Gaye Seye ◽  
...  
Keyword(s):  
Complex Formation ◽  
Thermodynamic Parameters ◽  
Initial Rate ◽  
Reaction Medium ◽  
Standard Entropy ◽  
Step Size ◽  
Formation Reaction ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Complex Formation Process

Abstract The aim of this work is to determine the thermodynamic parameters and the kinetics of complex formation between orthophthalaldehyde (OPA) and agmatine (AGM) in an alkaline medium (pH 13). Firstly, the association constant (Ka) between orthophthalaldehyde and agmatine was determined at different temperatures (between 298 K and 338 K) with a step size of 10 K. Secondly, the thermodynamic parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°),and Gibbs energy (∆G) were calculated, where a positive value of ΔH° (+45.50 kJ/mol) was found, which shows that the reaction is endothermic. In addition, the low value of ΔS°(+0.24 kJ/mol) indicates a slight increase in the disorder in the reaction medium. Furthermore, the negative values of ΔG between −35.62 kJ/mol and −26.02 kJ/mol show that the complex formation process is spontaneous. Finally, the parameters of the kinetics of the reaction between OPA and AGM were determined as follows: when the initial concentration of AGM (5 × 10−6 M) is equal to that of the OPA, the results show that the reaction follows an overall 1.5 order kinetics with an initial rate of 5.1 × 10−7Mmin−1 and a half-life of 8.12 min. The partial order found in relation to the AGM is 0.8. This work shows that the excess of OPA accelerates the formation reaction of the complex.

Effect of ECAP Processing on Hardness, Electrical Conductivity, and Precipitation Kinetics of the Cu-0.81Cr-0.07Zr Alloy

2021 ◽  
Author(s):  
Filipe Caldatto Dalan ◽  
Gisele Ferreira de Lima Andreani ◽  
Dilermando Nagle Travessa ◽  
Svetlana Faizova ◽  
Ilshat Albertovich Faizov ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Precipitation Kinetics ◽  
Ecap Processing ◽  
Kinetics Of

The mechanism of the oxidation of thiocyanate ion by peroxomonosulphate in aqueous solution. II. Kinetics of the reaction

1966 ◽  
Vol 19 (8) ◽  
pp. 1365 ◽  
Author(s):  
RH Smith ◽  
IR Wilson
Keyword(s):  
Aqueous Solution ◽  
Initial Rate ◽  
Stopped Flow ◽  
Thiocyanate Ion ◽  
First Order ◽  
Conductance Method ◽  
Rate Of Reaction ◽  
Kinetics Of

Initial rates of reaction for the above oxidation have been measured by a stopped-flow conductance method. Between pH 2 and 3.6, the initial rate of reaction, R, is given by the expression R{[HSO5-]+[SCN-]} = {kb+kc[H+]}[HSO5-]0[SCN-]20+ka[H+]-1[HSO5]20[SCN-]0 As pH increases, there is a transition to a pH-independent rate, first order in each thiocyanate and peroxomonosulphate concentrations.

scholarly journals Kinetics of rat liver glucokinase. Co-operative interactions with glucose at physiologically significant concentrations

1976 ◽  
Vol 159 (1) ◽  
pp. 7-14 ◽  
Author(s):  
A C Storer ◽  
A Cornish-Bowden
Keyword(s):  
Rat Liver ◽  
Glucose Concentration ◽  
Initial Rate ◽  
Constant Concentration ◽  
Hill Coefficients ◽  
Kinetics Of

The kinetics of glucokinase from rat liver were studied over wide ranges of glucose and MgATP2- concentrations. The initial rate shows a co-operative dependence on the glucose concentration, with Hill coefficients in the range 1.2-1.5. The degree of glucose co-operativity increases with the MgATP2- concentration, but no co-operativity was detected for the dependence of the rate on the MgATP2- concentration. The effects observed occur at physiologically reasonable concentrations of glucose and MgATP2- and are consistent with the presumed function of glucokinase in maintaining a constant concentration of glucose in the blood.

The Kinetics of Calcium Formate Pyrolysis in Potassium Bromide Matrix1

1965 ◽  
Vol 69 (2) ◽  
pp. 583-589 ◽  
Author(s):  
K. O. Hartman ◽  
I. C. Hisatsune
Keyword(s):  
Potassium Bromide ◽  
Calcium Formate ◽  
Kinetics Of

Kinetics of NO2 air space absorption in isolated rat lungs

1992 ◽  
Vol 73 (5) ◽  
pp. 1939-1945 ◽  
Author(s):  
E. M. Postlethwait ◽  
S. D. Langford ◽  
A. Bidani
Keyword(s):  
Steady State ◽  
Tidal Volume ◽  
Gas Phase ◽  
Initial Rate ◽  
Quasi Steady State ◽  
Closed Chamber ◽  
First Order ◽  
First Order Kinetics ◽  
Rat Lungs ◽  
Kinetics Of

We previously showed, during quasi-steady-state exposures, that the rate of inhaled NO2 uptake displays reaction-mediated characteristics (J. Appl. Physiol. 68: 594–603, 1990). In vitro kinetic studies of pulmonary epithelial lining fluid (ELF) demonstrated that NO2 interfacial transfer into ELF exhibits first-order kinetics with respect to NO2, attains [NO2]-dependent rate saturation, and is aqueous substrate dependent (J. Appl. Physiol. 71: 1502–1510, 1991). We have extended these observations by evaluating the kinetics of NO2 gas phase disappearance in isolated ventilating rat lungs. Transient exposures (2–3/lung at 25 degrees C) employed rebreathing (NO2-air) from a non-compliant continuously stirred closed chamber. We observed that 1) NO2 uptake rate is independent of exposure period, 2) NO2 gas phase disappearance exhibited first-order kinetics [initial rate (r*) saturation occurred when [NO2] > 11 ppm], 3) the mean effective rate constant (k*) for NO2 gas phase disappearance ([NO2] < or = 11 ppm, tidal volume = 2.3 ml, functional residual capacity = 4 ml, ventilation frequency = 50/min) was 83 +/- 5 ml/min, 4) with [NO2] < or = 11 ppm, k* and r* were proportional to tidal volume, and 5) NO2 fractional uptakes were constant across [NO2] (< or = 11 ppm) and tidal volumes but exceeded quasi-steady-state observations. Preliminary data indicate that this divergence may be related to the inspired PCO2. These results suggest that NO2 reactive uptake within rebreathing isolated lungs follows first-order kinetics and displays initial rate saturation, similar to isolated ELF.(ABSTRACT TRUNCATED AT 250 WORDS)

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