Design a procedure for determining the rate of reaction with respect to hydrogen ion. Use a guideline
Part 1: Determination of Rate wrt thiosulfate ion:
1.Using the 250 mL beakers, collect about 150 mL of 0.100 mol/L thiosulfate solution. Using the 100 mL beaker, collect about 60 mL of hydrochloric acid.
2.Construct a data table showing the initial molar concentration of thiosulfate ion, the time required for the reaction, and 1/Δt. Making three replications of this experiment and taking the average time for reaction of these three trials.
3. Determine the volume of 0.200 mol/L HCl reactant required to have an initial concentration of 0.010 mol/L in a TOTAL volume of 40.0 mL. (Take dilution into account!!) Add this volume of HCl to each of the 50 mL beakers. Note these volumes, and calculate what volume of water must be added to each beaker to ensure the total volume will be 40.0 mL.
4. Determine the amount of 0.100 mol/L S2O3 2- solution needed to have initial concentrations of thiosulfate of 0.020, 0.040, 0.060, 0.080, and 0.095 mol/L in a TOTAL volume of 40 mL.
5.Add the volume of water needed for each beaker as calculated in step 4 (Take the volume of HCL already added into account!)
6. Ensure that the button of your 50 mL beakers is dry. Place the beaker onto the filter paper so that the “X” can be clearly seen when viewed from above.
7. Add the calculated volume of thiosulfate solution and start the stopwatch. Start with the most concentrated solution. One partner views the reaction from above while the other times the reaction. When the “X” is no longer CLEARLY visible, stop the watch and record the elapsed time (in seconds), and enter it into a data table. Then, calculate the value for 1/Δt.
Note: Exactly when the “X” is ‘no longer clearly visible’ is a judgment call. It is important that the SAME OBSERVER make this decision. In any event, you should not wait for any longer than 10 minutes (300 seconds) for a reaction to occur. In the event that no reaction has occurred within 10 minutes, record the time value as “>600s”.
8. Repeat steps 6 and 7 for each of the other four beakers. When finished, dump the contents of the beaker into the waste container in the fumehood.
9. Repeat the experiment to get a total of three sets of data. Take the average values for Δt and 1/Δt.
10. Plot a graph of 1/Δt vs initial [S2O3 2-] and determine the order of the reaction. (Write
the second plot of 1/Δt vs [S2O3 2-])