Activation energy

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  • Experimental Conditions Lab Report

    Excel’s calculations for Linear Regression. The function, ퟏ−(ퟏ−휶) ⅓, is dimensionless. Therefore, the rate constant is k_s [=] 1/min as it balances out the unit for time. Question 2: (ii) Plot Rate Constants’ natural log vs 1/T. Fit a straight line, estimate Activation Energy (kJ/mol), and pre-exponential factor A (units?). Note: each test must use the same leaching model to find activation energy! Table 22: Data for Q2(ii) Plot The Arrhenius Equation equates the rate constant (k) to activation energy (EA): This equation is mimicked by the trendline in our plot. We see that to find activation energy, we must take the slope of y = -9717.9x + 27.063 and multiply it by (-R): The pre-exponential factor (A), also know as the frequency factor, can be found similarly by the intercept: A’s units must match the rate constant units as the exponential term is dimensionless, thus A [=] 1/min. Question 2: (iii) Is the activation energy consistent with the chosen leaching model? It is stated in the lab manual that the activation energy of ion diffusion in an aqueous solution is typically less than 25 kJ/mol, whereas the activation energy for a surface chemical reaction control is around 42 to 105 kJ/mol. As our estimation of activation energy is around 81 kJ/mol, it appears we correctly chose our model. Question 3: (i) A PbS particle with initial size r_o1 and rate constant k_s1 has the size r_o2 and rate constant k_s2 at some specified temperature. Use k_s=(V_m k^ ' f(C_B^o ))/r_o to…

    Words: 2081 - Pages: 9
  • Experiment 4: Kinetics Of Nucleophilic Substitutions

    chloride, which further indicates that the reaction follows a SN1 mechanism. 4. Calculate the activation energy (Ea) for this reaction. To do this, you need to construct an Arrhenius plot. First, complete the following table. Experiment Temp. (K) Reaction time (s) Reaction rate (M/s) Rate constant k (s-1) 1 295.15 65 4.89 · 10-5 1.62 · 10-3 6, trial 1 283.15 200 1.58 · 10-5 5.27 · 10-4 6, trial 2 285.15 180 1.58 · 10-5 5.28 · 10-4 7, trial 1 313.15 30 1.05 · 10--4 3.50…

    Words: 1172 - Pages: 5
  • Semiconductive Properties Of Metal Oxides

    the increase of the charge carriers that can overcome the energy barrier and participate in the electrical conduction where in metal complexes, the metal atoms act as charge carriers reservoir supply the complex with the free electrons and the metal ion can act as a bridge to facilitate the flow of current. To illustrate the effect of the metal type on the electrical resistivity of the ligand, isothermal…

    Words: 861 - Pages: 4
  • Temperature Dependence Of D. C. Electrical Resistivity

    When chromium is doped in cobalt ferrites, a partial replacement of Fe3+ ions by Cr3+ ions take place in octahedral (B) site because, Cr ions have strong octahedral site preference. As a consequence, the substitution of Cr in Cobalt Ferrites would decrease the number of Fe3+/Fe2+ ion pairs present at the octahedral sites resulting in a decrease in hopping of ions and increase in resistivity. The increase in resistivity may also be due to the increase in activation energy (Table 2) with increase…

    Words: 1962 - Pages: 8
  • Potassium Permanganate Lab Report

    The plots for GAT, AGAT and DAGAT were straight lines, and the standard deviations were almost 1 for each, which indicate the independency of the thermal degradation of the energetic materials at various heating rates. However, the standard deviation for AZT was slightly less than that of the others. (27), (33), (40) The slopes of the lines equal for each material -Ea /R (2) through…

    Words: 1161 - Pages: 5
  • Eyring Factors: An Analysis Of Dielectric Loss Factor Values

    The Gibb’s free energy change is the driving force and the fundamental criterion of spontaneity. Physical absorption is to be a spontaneous thermodynamic process, mush have a negative value. The thermodynamics parameters of adsorption relaxation strength (Δε) and dielectric activation (ΔF) of stearic acid complex have been calculated and the results are tabulated (3a-3f) using this formula(47) Δε = ε0 - ε∞ and ΔF = ε0 – ε’. The thermodynamic parameters of adsorption of stearic acid complex are…

    Words: 793 - Pages: 4
  • Al2o3 Composites Lab Report

    composite has been investigated. For that purpose, the PMMA samples with Al2O3 additive prepared with different percentages(0,15,25,35 and 45) wt.% and different thickness. The experimental results showed that the D.C electrical conductivity increased with increasing the alumina concentrations and temperature. Also the activation energy change with increasing of additional alumina. The dielectric constant, dielectric loss, A.C electrical conductivity are changed with change the concentration of…

    Words: 1815 - Pages: 8
  • Enargitite And Arsenic Analysis

    Ciminelli and Osseo-Asare, 1995; Lowson, 1982). Anderson (1951) reported 26 kJ/mol in the study of oxidation kinetics of galena (PbS) while Stenhouse and Armstrong (1952) reported an activation energy of 20 kJ/mol for the alkaline oxidation of pyrite. Koslides and Ciminelli (1992) suggested that during alkaline oxidation of sulphides, there is a change from chemical (activation energy > 40 kJ/mol) to diffusion (activation energy < 40 kJ/mol) control as the rate determining step when…

    Words: 1682 - Pages: 7
  • Charge Transport: Worksheed By Vissenberg And Matter Model

    a long distance with low activation energy or hop over a short distance with high activation energy [22-25, 58]. A crucial feature of the VRH model is the determination of the density of states (DOS).…

    Words: 1004 - Pages: 5
  • Thermal Effect Lab

    K1 is the forward reaction coefficient of the first equation and K2 is for the second one. K1=F1*7.6*〖10〗^10*exp⁡(-(38000*A1)/Tb) K2=F2*4.1*〖10〗^10 Where F1 is the N2 Oxidation rate multiplier, F2 is the N Oxidation rate multiplier, F3 is the OH Oxidation rate multiplier, A1 is the N2 Oxidation Activation temperature multiplier, A2 is the N Oxidation Activation temperature multiplier and TB is the burned sub-zone temperature in Kelvin. The formation of NO during equation 1 is much slower than…

    Words: 984 - Pages: 4
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