First hook the rubber tube from the Bunsen burner to a gas source, then take a match and turn on the gas source. Once the gas is on light the match and then light the bunsen burner. (MAKE SURE TO NOT BURN YOURSELF)!!
Place the lit bunsen burner underneath the tripod so it can begin to heat the 1 liter beaker with the 700 mL of room temperature water from the sink.
Insert a thermometer into the 1 liter beaker that is being heated and adjust the flame of the bunsen burner so it will heat the water to a temperature of about 30°C.
Take the 10 mL pipette and the 10 mL-graduated cylinder use the pipette and transfer 4 mL of H2O2 and using a 10 mL pipette transfer 4 mL of H2O2 from a container into the 10 mL graduated cylinder.
Take a 10 mL test tube and add fill 4 mL of H2O2 from the 10 mL graduated cylinder into the 10 mL test tube. Once that is done, take a rubber stopper and seal the 10 mL test tube containing the H2O2. Use the test tube holder to hold the test tube into the 1 liter beaker the is being heated to a temperature of about 30°C. Make sure that the majority of the test tube is submerged in water.
Using the other 10 mL pipette, transfer 1 mL of 0.5 M Yeast into the other 10 mL graduated cylinder. From this graduated cylinder, transfer the 0.5 M Yeast to a new 10 mL test tube; seal the test tube with a new solid rubber stopper. With the other test tube holder, place this test tube containing 1 mL of 0.5 M Yeast into 1 liter beaker that is currently being heated to a temperature of about 30°C.
Turn on a computer and start the LoggerPro Program.
Connect the Gas Pressure Senor to Channel 1of the Vernier computer interface and with the correct cable attach the Vernier computer interface to the computer.
Take the plastic tubing with the Leur-lock connectors at either end of the tubing, connect the tubing to the base on the one-hole rubber stopper and the other end of the plastic tubing, it must be connected to the white stem on the end of the Gas Pressure Sensor called a Luer-lock. (MAKE SURE THE PLASTIC TUBING TIGHTLY SECURED OR THE GAS WILL ESCAPE AND IT WILL LEAD IT IN ACCURATE READINGS).
Once the LoggerPro Program has been opened make sure that the label on the x-axis is time in seconds and that the units on the y-axis is pressure in kPa before collecting the data.
Leave the test tubes in the water bath for at least two minutes so that the solutions in the test tube have a temperature of around 30°C. Once the water is about 30°C, record this temperature into a data table. When two minutes have passed by, commence the reaction and collect the pressure data. Remove both test tubes from the water by holding onto the test tube holder, place them in a test tube rack and remove each seal from the test tubes. Transfer the yeast solution from its test tube into the test tube containing H2O2 solution and shake lightly to mix the two solutions together.
As quick as possible seal the test tube with the one-hole stopper connected to the Gas Pressure Sensor and place the test tube back into the water by holding the test tube with the test tube holder. Next click collect data on the LoggerPro Program to begin collecting data. (THE LAST TWO STEPS ARE CRUCIAL AND MUSTBE DONE AS QUICK AS POSSIBLE TO AVOID ANY EXTERNAL INFLUENCES).
It is needed to collect the data for three minutes once three minutes is up, carefully remove the test tube from the water by holding onto the test tube holder and set it in the test tube rack. Next slowly and carefully begin to tale out the stopper from the test tube allowing the gas pressure to escape.
Store the results from the first trial by selecting Store Latest Run from the Experiment menu. After doing this a table of data and the graph will be saved. Then make sure to clean and trash the solution that is in the test tube. Repeat the first part another two more time so you can have three trials in total. Then print the graph and the full data table from each trial.
Part 2 of the experiment: Decomposing 1.5 % of H2O2 solution with 0.5 Yeast at about 30°C
Take a 10 mL graduated cylinder and using a 10 mL pipette (make sure you are using the same pipette for the H2O2 as in previous trials and don’t interchange this pipette for the one being used with Yeast) fill 2 mL of H2O2 from the same container like it was done in part 1 into the 10 mL graduated cylinder. Once that is done insert 2 mL of distilled water as well into the graduated cylinder containing H2O2.
Now grab the 10 mL test tube (which has been thoroughly washed with water) and insert the 4 mL of H2O2 which has been mixed with the distilled water from the 10 mL graduated cylinder into the 10 mL test tube. Then take the 10 mL test tube and with the H2O2 seal it with a rubber stopper. Use the test tube holder so you can place the test tube in the 1 liter beaker that is being heated to 30°C. Be sure that the test tube is deep enough in the 1 liter beaker.
Using the other 10 mL pipette, take the 1 mL of 0.5 M yeast and our it into the other 10 mL graduated cylinder. Then grab the graduated cylinder and put the 0.5 M yeast to a new 10 mL test tube; close the test tube so no air comes in with a new rubber stopper. With the other test tube holder, place this test tube containing 1 mL of 0.5 M KI into 1 liter beaker that is currently being heated to a temperature of about 30°C. Repeat steps 13-18 from part I.
Part 3 of the experiment: Decomposing 0.75 % of H2O2 solution with 0.5 Yeast at about 30°C
Take a 10 mL graduated cylinder and using a 10 mL pipette (make sure you are using the same pipette for the H2O2 as in previous trials and don’t interchange this pipette for the one being used with KI) transfer 1 mL of H2O2 from the same container like in part I into the 10 mL graduated cylinder. Add 3 mL of distilled water into the graduated cylinder containing H2O2. Mix the solution gently.
Take a 10 mL test tube (which has been cleaned after previous trials) and transfer 4 mL of H2O2 mixed with distilled water from the 10 mL graduated cylinder into the 10 mL test tube. Then seal the 10 mL test tube containing the H2O2 with a solid rubber stopper. With one of the test tube holders, place the test tube into the 1 liter beaker that is currently being heated to a temperature of about 30°C. Make sure that the majority of the test tube is submerged in water.
Using the other 10 mL pipette, transfer 1 mL of 0.5 M yeast into the other 10 mL graduated cylinder. From this graduated cylinder, transfer the 0.5 M yeast to a new 10 mL test tube; seal the test tube with a new solid rubber stopper. With the other test tube holder, place this test tube containing 1 mL of 0.5 M yeast into 1 liter beaker that is currently being heated to a temperature of about 30°C. Repeat steps 13-15 from part 1.
Part 4 of the experiment: Decomposing 3.0 % of H2O2 solution with 0.5 Yeast at about 35°C
For this part repeat the steps 6-7 and 13-15 from part 1. The only thing that is needed to be changed is that the water needs to be about 35°C.
Part 5 of the experiment: Decomposing 3.0 % of H2O2 solution with 0.5 Yeast at about 40°C
For part 5 redo the steps 6-7 and 13-15 from part 1. The only thing that is needed to be changed is that the water needs to be about 40°C.
Steps once all the five parts of the experiment are complete
Now look at the data table that has been filled in for each trial from each and calculate the average reaction rate (kPa sec-1) of the decomposition of H2O2 that occurred over 3 minutes for each part and put it into the analysis table
Insert the concentration of H2O2 and yeast from each part into the analysis table as well.
Make sure to find the average temperature (°C) and include it in the analysis table.
Then compare and contrast the different effects the rate o reaction caused by the change in concentration of H2O2 and in the change of temperature.
(The data table is an example of the data table that will be printed from the computer after each trial and part is done from LoggerPro Progam. The only thing is that it will record the gas pressure until 3 minutes. Again only an example how it should look like).
by
guitaribanez (student)
