Decomposition of Hydrogen Peroxide Worksheet PDF

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Decomposition of Hydrogen Peroxide Worksheet for chemistry 222...

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Decomposition of Hydrogen Peroxide Worksheet: There is not a formal lab report for this lab. Complete the below pages and submit them to your TA in the dropbox Name_____________________________ Date______________ Provide a brief statement of the purpose of this activity. Be sure to include a description of the chemical reaction (include a balanced chemical reaction). Describe how the gas was produced and collected. Describe the purpose of the catalyst. Describe why one needed to utilize Dalton’s Law in the calculation. The purpose of this lab is to find the decomposition rate of hydrogen peroxide. This is done by using the differential/Dalton’s law to calculate the rate of decomposition with different concentrations of hydrogen peroxide. The concentration of a reactants is proportional to reaction rate. A higher reaction rate means the solution is of higher concentration, and vice versa, a lower reaction rate means the solution is of lower concentration. A catalyst is needed for hydrogen peroxide due to the rate of decomposition of hydrogen peroxide being slow on it’s own. In this case, we are using potassium iodide as a catalyst in order to measure the volume of oxygen gas produced through the decomposition reaction. In the three trials the mass percent of hydrogen peroxide was 5.9%, 6.3%, and 5.5%.

Rate = K ( H2O2)a (KI-)b KI2 H2O2 (aq)  2H2O (I) + O2 (g) P = Σ Pi + P1 + P2 PO2 = Ptotal – PH2O Data Table Include a nicely formatted data table that shows all the relevant data, including units. Table 1: Trials 1-3: Volume, Mass, and Temperature Vapor Pressure ( Pressure constant: H2O2 at 747.6 mmHg) Trial Volume Volume Tempurat Vapor Mass (mL) (mL) Pressure H2O2 ure (Co) Initial Final (torr) Solution (g) 1 3.1 94.2 22.00 18.8 4.03 2 3.5 96.1 21.01 18.6 4.21 3 3.3 94.7 22.90 19.3 4.37 .

Step-By-Step Analysis 1. Using data from one of your trials, show a sample calculation for the determination of Poxygen , include a detailed annotation describing any equation and any value that was used. 2. Using data from the above trial, show a sample calculation for the determination of the Voxygen, include a detailed annotation describing any equation and any value that was used. 3. Using data from the above trial, show a sample calculation for the determination of the number of moles of oxygen, include a detailed annotation describing any equation and any value that was used. 4. Using data from the above trial, show a sample calculation for the determination of the mass of hydrogen peroxide in the solution, include a detailed annotation describing any equation and any value that was used. 5. Using data from the above trial, show a sample calculation for the determination of the mass percent of hydrogen peroxide in the solution, include a detailed annotation describing any equation and any value that was used. 6. Using data from the above trial, show a sample calculation for the determination of the percent error, include a detailed annotation describing any equation and any value that was used.

During this lab, we were able to find the mass percent of hydrogen peroxide through a decomposition reaction using KI as a catalyst. In the three trials the mass percent of hydrogen peroxide was 5.9%, 6.3%, and 5.5%. Percent errors that were calculated were 3.3%, 10%, and 16.6%. There is some variation in the results and percent errors which would be due to technology issues or calculation issues. Even though the objective of the lab was still accomplished by finding the percent mass of H2O2. The percent of each trial was higher than 3% which is common mass percentage of hydrogen peroxide, which it should have been at least closer than the accepted value of 3%. Hence, why there may have been technology or calculation errors, assuming atmosphere pressure is equal to the pressure of the samples. Post Lab Questions

1. Would the results of the activity be impacted If the same procedure were done on a different day in which the temperature of the lab space was significantly cooler? Provide reasoning and assumptions for your response.

Since it was online it wouldn’t have been affected in the same way as an inperson lab. However, most enzyme reactions rates are higher when heat is increased, so I think it is safe to say that heat could increase decomposition rates. I don’t think that the heat of a room would be enough to cause a significant change unless the room was unreasonably warm.

2. One year the chemistry stockroom accidentally substituted 30% hydrogen peroxide in place of the expected 3% solution. Using the exact same procedure, equipment, and technique why were students unsuccessful in measuring the percent composition of the solution? What probably happened? Provide two potential modifications to the procedure that would allow an accurate determination of the composition of the solution. This is just assumption, but I would guess that the higher percentage could have reacted with the KI more intensely than a lower percentage. I know that typically 30% hydrogen peroxide isn’t commonly used and is usually diluted significantly for medical and cleaning uses. I would assume that 30% can be dangerous as well. So if you mixed it with a reactant at such a high concentration I would just assume it would fizz up really fast or something along those lines....