Elephants Toothpaste
Introduction:
Aim: To see if the experiment is endothermic or exothermic and to see which percentage of hydrogen peroxide (H2O2)
Hypothesis: The experiment is exothermic and the hydrogen peroxide with the highest percentage will have the highest temperature change.
Materials:
* 2% H202
* 4% H202
* 6% H202
* 8% H202
* 10% H202
* 0.1m KI (potassium iodide)
* 1m KI (potassium iodide)
* 5 test tubes
* Test tube rack
* 3 thermometers
* Plastic pipette, 3ml
* Measuring Cylinder, 20ml
Method:
1. Gather materials and safety equipment
2. Measure 10ml out of the 5 different Hydrogen Peroxide
3. Pour the amounts of H202 in separate test tubes.
4. Record the starting temperatures from each test tube of H202
5. Measure out 2ml of 0.1m & 1m KI (Potassium iodide) in the plastic pipette
6. Add 2ml of 0.1m & 1m KI into each test tubes of H202
7. Record the end temperature from the test tubes
H2O2 | KI | Start Temp | End Temp | Difference |
| | | | |
2% | 0.1m | 20 | 23 | 3 |
4% | 0.1m | 21 | 23 | 2 |
6% | 0.1m | 20 | 25 | 5 |
8% | 0.1m | 21 | 24 | 3 |
10% | 0.1m | 22 | 25 | 4 |
| | | | |
2% | 1m | 22 | 29 | 7 |
4% | 1m | 20 | 25 | 5 |
6% | 1m | 21 | 40 | 19 |
8% | 1m | 23 | 55 | 32 |
10% | 1m | 22 | 65 | 43 |
Discussion: The class results indicate that every test would have a higher temperature at the end. As can be seen from the graph, the higher concentrated Hydrogen Peroxide makes the temperature higher and the lower concentrated would have a little temperature change. As the temperature increases, the bubbles rise in the test tube making the elephant’s toothpaste.
From the graph, it can be seen that some recordings may be wrong. To improve the accuracy of the results, the thermometer should be left in the test tube until the very end of the experiment. Also repeating the test again may improve the accuracy. The class also...