college of engineering and computer science to: drs....

THE J COMPANY

615 McCallie Avenue

College of Engineering and Computer Science

Chattanooga, TN 37403

Jordan Hughes - zcb449@mocs.utc.edu

John Thetford - tkj184@mocs.utc.edu

Jonathan Cain - gpq633@mocs.utc.edu

To: Drs. Henry and Ennis

From: J Project Engineers

Re: Reaction Studies Report

Date: December 3, 2013

The J Company has recently been assigned an experiment to investigate the impact of

temperature and concentration on the rate of reaction. The rate of reaction was also investigated

after the platinum catalyst had been used 31 times.

The decomposition of hydrogen peroxide is a thermodynamically favorable process. This

reaction will occur naturally at a prescribed rate that is dependent on temperature. A platinum

catalyst is used in this experiment.

The J Team’s findings are compiled in the report below. The J Team had assistance from Team

Gray in the junior. Some of the data collected and analyzed from the junior team was used to

help compile the report below. Please give any and all necessary feedback and comments to

better this report.

Thank you,

J Project Engineers

Rate of Reaction Studies

UTC College of Engineering and Computer Science

ENCH 4350

J Team

Jordan Hughes

Jonathon Cain

John Thetford

Report Submitted To: Drs. Henry and Ennis

December 3, 2013

ABSTRACT

The purpose of this experiment is to study the reaction kinetics of a 3% hydrogen peroxide

solution. The experiment will allow for the effects of temperature and concentration on the

reaction completion time to be investigated. The over the counter contact solution used stated to

not use the container after 31 uses. Therefore, the effectiveness of the platinum catalyst container

after 31 uses was also investigated.

After completing each trial, it was concluded temperature and concentration affect the reaction

completion time of the reaction of hydrogen peroxide with the platinum catalyst. An increase in

temperature will decrease the average reaction completion time. The more dilute the hydrogen

peroxide with water, the faster the average reaction completion time. After the platinum catalyst

container has been used 31 times, its effectiveness is decreased. This was expected because the

over the counter contact solution used stated on the box that it should not be used after 31 uses.

Table of Contents

ABSTRACT .................................................................................................................................................. 3

INTRODUCTION ........................................................................................................................................ 5

THEORY ...................................................................................................................................................... 6

EQUIPMENT ............................................................................................................................................... 7

PROCEDURE ............................................................................................................................................... 9

RESULTS ................................................................................................................................................... 10

DISCUSSION OF RESULTS ..................................................................................................................... 15

CONCLUSIONS......................................................................................................................................... 16

APPENDIX ................................................................................................................................................. 17

Tables and Figures Table 1: Average reaction completion time for pure hydrogen peroxide. ................................................. 10

Table 2: Average reaction completion time for the 1:1 dilution. ............................................................... 10

Table 3: Average reaction completion time for the 1:2 dilution. ............................................................... 11

Table 4: Average reaction completion time for 1 Celsius. .......................................................................... 11

Table 5: Average reaction completion time for 50 Celsius. ........................................................................ 12

Table 6: Average reaction completion time for 75 Celsius. ........................................................................ 12

Table 7: Uncertainty Calculation Table. ...................................................................................................... 17

Figure 1: 3% Hydrogen Peroxide solution used during the experiment. ...................................................... 7

Figure 2: Glass beaker containing the platinum catalyst containers on the Fisher Scientific Isotemp

stirring hot plate. .......................................................................................................................................... 7

Figure 3: Close up of the reaction taking place in the platinum catalyst container. .................................... 8

Figure 4: Effects of Temperature on the Reaction Completion Time. ........................................................ 13

Figure 5: Effects of Concentration on the Reaction Completion Time. ...................................................... 13

Figure 6: Investigation of the platinum catalyst after 31 uses. .................................................................. 14

INTRODUCTION

The purpose of this experiment is to study the reaction kinetics of a 3% hydrogen peroxide

solution. The experiment will allow for the effects of temperature and concentration on the

reaction completion time to be investigated.

The rate of a chemical reaction depends on many variables such as temperature, concentration,

pressure and presence of catalysts. Two easily measureable changes to a reaction are the

adjustment of temperature and concentration. This experiment measures the differing reaction

completion times based off of differing temperature and concentrations of the reactants.

The reaction studied is the catalytic decomposition of hydrogen peroxide.

2��������→ 2����� �����

It is a spontaneous reaction at normal conditions, but is very slow. Using a catalyst the reaction

can proceed at a rate that is easily measurable and visually cueing as to when the reaction is

complete.

The 3% hydrogen peroxide solution is a common over the counter contact cleaning solution. A

platinum catalyst container is included in each box of cleaning solution. The hydrogen peroxide

solution reacts with the platinum catalyst. The reaction completion time will vary with

differences in temperature and concentration.

The over the counter contact cleaning solution gives the warning to not use the platinum catalyst

container after 31 uses. This was investigated by senior management and the junior team. The

same platinum catalyst container was used for all trials.

THEORY

The catalytic decomposition of hydrogen peroxide reaction is shown below.

2��������→ 2����� �����

The decomposition of hydrogen peroxide is a thermodynamically favorable process. This

reaction will occur naturally at a prescribed rate that is dependent on temperature or

concentration. When a catalyst is introduced to the reaction, the rate will speed up to the point

that bubbling will be visible. The catalyst used during this reaction is platinum.

The decomposition of hydrogen peroxide is a spontaneous reaction at standard temperature and

pressure. The change in entropy and enthalpy of the reaction dictates that the reaction will occur

spontaneously. ∆�� ��������� � � ���������

∆�� �2��285.83� 0� � �2��187.78�� �196.1 "#$�

∆�% ��������� � � ���������

∆�% �2�69.91� 205.138� � �2�109.6�� 125.758 #& ∗$�

The entropy is positive, indicating an increase in disorder of the system. The enthalpy is

negative indicating that heat is produced by the reaction. Gibbs energy of reaction:

∆�( ∆�� � )∆�%

Results in a ∆�( of -233,560 J/mol., confirming that the reaction is spontaneous at normal

pressure and temperature.

EQUIPMENT

The equipment used during the decomposition of hydrogen peroxide experiment was a glass

beaker, 10 mL graduated cylinder, precision balance, Fisher Scientific Isotemp stirring hot plate,

a platinum catalyst container, potassium iodide to control temperature, and a stop watch. The

precision balance used was a Mettler XP Analytical scale. Potassium iodide requires energy to

break the bonds between the potassium and iodine ions which are received from the water. This

will cause the temperature of the water to drop. The potassium iodide was only used for the

temperature trials at 1°C. The Fisher Scientific Isotemp stirring hot plate was used for the

temperature trials at 50 °C and 75°C.

Figure 1: 3% Hydrogen Peroxide solution used during the experiment.

Figure 2: Glass beaker containing the platinum catalyst containers on the Fisher Scientific

Isotemp stirring hot plate.

Figure 3: Close up of the reaction taking place in the platinum catalyst container.

PROCEDURE

The procedure allowed for repeatability of the experiment.

1. Measure 6 mL of the hydrogen peroxide solution into a graduated cylinder.

2. Pour the contents into the platinum catalyst and immediately weigh the solution to the

nearest 0.001 g on a precision balance. Start the timer immediately.

3. Record the initial weight.

4. Record the reaction completion time for three trials at 1°C, 50°C, and 75°C, and three

trials of pure hydrogen peroxide, 1:1 dilution, and 1:2 dilution.

5. After the above 18 trials, continue running trials at 75°C and at a 1:2 dilution until more

than 31 trials have been completed. Be sure to use the same platinum catalyst container

for all trials.

6. Compile all of the data into tables and graphs.

7. Investigate the effects of temperature, concentration, and 31 uses on the reaction

completion time.

RESULTS

The data for each trial of the decomposition of hydrogen peroxide is shown in Tables 1-6 below.

Sample calculations of the uncertainty can be found in the Appendix.

Table 1: Average reaction completion time for pure hydrogen peroxide.

Table 2: Average reaction completion time for the 1:1 dilution.

Table 3: Average reaction completion time for the 1:2 dilution.

Table 4: Average reaction completion time for 1 Celsius.

Table 5: Average reaction completion time for 50 Celsius.

Table 6: Average reaction completion time for 75 Celsius.

Figure 4: Effects of Temperature on the Reaction Completion Time.

Figure 5: Effects of Concentration on the Reaction Completion Time.

Figure 6: Investigation of the platinum catalyst after 31 uses.

DISCUSSION OF RESULTS

Figure 1 above indicates that temperature has an effect on the reaction completion time. An

increase in temperature will speed up the reaction completion time. Figure 2 above indicates that

concentration has an effect on the reaction completion time. The more dilute the hydrogen

peroxide solution, the faster the reaction completion time.

Figure 3 above shows the investigation of 31 uses on the platinum catalyst container. This was

investigated at different temperatures only. After 10 trials at 0°C, 50°C, and 75°C, the remainder

of the trials was performed at 75°C for time purposes. The same platinum catalyst was used for

all trials. From Figure 3, it can be seen that after the platinum catalyst has been used 31 times, its

effectiveness slowly starts to be altered. This can be seen by the squares. The reaction

completion time is longer that previously recorded at 75°C after 31 uses.

CONCLUSIONS

After completing each trial, it was concluded temperature and concentration affect the reaction

completion time of the reaction of hydrogen peroxide with the platinum catalyst. An increase in

temperature will decrease the average reaction completion time. The more dilute the hydrogen

peroxide with water, the faster the average reaction completion time. After the platinum catalyst

container has been used 31 times, its effectiveness is decreased. This was expected because the

over the counter contact solution used stated on the box that it should not be used after 31 uses.

APPENDIX

Sample Calculation of the Uncertainty of Reaction Time

Table 7: Uncertainty Calculation Table.

95 % Confidence

(Xmax – Xmin)*t/n

= (14.00 – 13.41)*2.9/3.0

= 0.57 min