question 1-3

(1) Plot In(absorbance) against time for each kinetic run and determine and the pseudo-first order rate constants, k', for each individual run from the slopes. Hint. What is the concentration of NaOH in each run? (2) Plot log1ok', against log 10[NaOH). and determine the reaction order with respect to NaOH i.e. ß from the slope.(This value should be 1 within experimental error). (3) Assuming B = 1 plot k' against [NaOH]and determine the second order rate constant, k, from the slope (include units and reaction temperature). Use excel to calculate the error on the rate constant k (+20). The experiment was carried out according to the following method Zero the spectrometer at 800 nm and carry out a baseline correction over the wavelength range 800 - 400 nm. Record the Visible spectrum of the malachite green stock solution between 800 and 400 nm and find the door Prepare four solutions of NaOH by diluting the stock solution given by a factor of two each time. Set the following scan conditions on the UV spectrometer for the kinetic run: MODE: KINETIC WAVELENGTH: doux LAG TIME: 0 REACTION TIME: (this value will depend on the reactant concentrations and must be found by trial and error) TIME INTERVAL: (This value depends on the REACTION TIME. You will need to record no more than 10 absorbance values as a function of time). Zero the spectrometer using water in both sample and reference. Remove the cuvette from the sample beam and add exactly equal volumes of malachite green stock solution and NaOH solution (start with highest concentration) simultaneously using Pasteur pipettes. Shake rapidly and quickly place in the spectrometer. Press RUN and record the decay of the malachite green. Repeat for each of the other NaOH solutions using the same stock malachite green solution. Ensure you record the temperature of the reaction mixture!! The experiment was carried out at room temperature (20 °C) with the collected results shown in the table below. Time (s) 0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 Room Temperature (RT) [NaOH) [NaOH) [NaOH) [NaOH) 0.05 M 0.025 M 0.0125 M 0.00625 M Absorbance Absorbance Absorbance Absorbance 0.4183 0.449 0.4841 0.5331 0.2264 0.321 0.3978 0.4797 0.1235 0.2328 0.329 0.433 0.0682 0.173 .2739 0.3887 0.0381 0.124 0.2288 0.3508 0.0215 0.0917 0.1899 0.318 0.0129 0.0667 0.1567 0.2878 0.0502 0.1309 0.2605 0.0385 0.1112 0.236 0.0292 0.0928 0.2137 0.0249 0.0768 0.1938 0.0192 0.0618 0.1747 0.0161 0.051 0.1576 0.0427 0.1431 0.0353 0.1292 0.0291 0.1171 0.1061 0.0956