To find the activation energy (E_a) of a particular reaction using the Arrhenius
ID: 971621 • Letter: T
Question
To find the activation energy (E_a) of a particular reaction using the Arrhenius equation, students measured the rate constant (k) of this reaction at varying temperature. They obtained a linear Arrhenius plot of (ln k) vs. (1/T) shown below, with the negative slope = - 3.8 Times 10^3. What is the activation energy. E_a, for this reaction in kJ? Useful information: R = 8.31 J/K mol. In a spectrophotometry experiment, a series of standard solutions of a colored substance X were prepared and their absorbance measured using a 1.0-cm cuvet. The following calibration Beer's Law plot Absorbance vs. Concentration was obtained. What is the value of molar absorptivity coefficient, E, for substance X? For a particular colored compound X, the molar absorptivity coefficient t: was found to be 1.45 Times 10^4 L/(mol cm). The unknown concentration solution of compound X placed in a 1.00-cm cuvet showed the absorbance A = 0.652. What is the molarity of X in the unknown solution?Explanation / Answer
8. according to beers lamberts law
From the given data A=0.652, l=1cm and 1.45x104
Now concentration c=A/
0.652/1.45x104 =0.449x10-4 M