equation 2b is intial rate= -delta H2O2/delta T =-1/2[S2O3^2-]^0/delta T = K' [H2O2]^ao
Burette 10 mL of sodium thiosulfate solution (record exact volume) into a clean 250 mL Erlenmeyer flask. Using a 50 mL pipette, next add 50 mL of buffered iodide solution containing the starch indicator. In a clean 150 mL beaker burette 10 mL of stock H_2 O_2(aq) and 20 mL of distilled water (again recording the exact volumes). All at once: pour the diluted H_2 O_2 into the flask and start timing. Swirl the contents and measure the time interval (plusminus 1 s) between mixing and the appearance of colour. Finally, measure and record the temperature of the flask contents. Immediately after mixing (i.e., before any reaction has occurred), what are the initial concentrations of H_2 O_2; and S_2 O_3^2- after the four stock solutions have been combined in step 1 of the procedure? Assume that the stock H_2 O_2 and Na_2 S_2 O_2 solutions are 0.210 and 0.0200 mol L^-1, respectively, and that the volumes specified in the procedure were buretted exactly. A blue colour appears exactly 3 min 5 s after the reagents are combined. What concentrations of H_2 O_2 and S_2 O_3^2- have reacted at the instant this happens? Calculate the initial rate of reaction for this hypothetical case. (Refer to equation 2b.)
