Riley, Tenzin, and Roc 11 CBEE 101

Reactions Vinegar and Baking Soda CH 3 COOH (aq) + NaHCO 3 (s/aq) ---> CH 3 COONa (aq) + H 2 O (l) + CO 2 (g) This is the main reaction used at first until we both got approval for an alternative reaction and had a bottle that would seal properly. Aluminum and Sodium Hydroxide 2 Al (s) + 6 NaOH (s/aq) --> 2 Na 3 AlO 3 (s/aq) + 3 H 2 (g) The NaOH comes in a pellet form and there for must have water to dissociate the pellets to have the reaction occur. This reaction was our original alternative but we found our before testing it that it is highly exothermic and would not be supported. Hydrochloric Acid and Baking Soda NaHCO 3 (s) + HCl(aq) --> NaCl(aq) + H2O(l) + CO 2 (g) Water was added before NaHCO 3 to catalyse the reaction and also to insure a full reaction occured by helping disolve the baking soda. The Baking soda was used as the limiting factor and the Hydrocholric was used in excess. A 1: 1 ratio between baking soda and CO 2 (g) allowed us to know that for every mole of baking soda we added a mole of gas was produced. Predictions for HCl reaction ATMBaking Soda Grams

Our Chemical Reaction Car BeforeAfter

Results AtmospheresCar OriginalCar Final This showed us that with our Original car we needed closer to 5 atmospheres of pressure and with the final car we needed 4.85 atmospheres to achieve close to the targeted distance of 25 feet.

Conclusion During this lab we incurred many problems with small increments of success. Our first problem was that of a leaking bottle and switching our caps, bottles and using different substitutes for Teflon tape until Teflon tape became available. Out next issue was that our car was poorly designed, it was bulky and had way to much stuff on it. We incurred a difficulty finding proper Kenex at first to make the car which in turn made a Frankenstein. After receiving proper wheels we had redesigned our car to be much more effective. We found out during the semi finals that our wheels were causing huge amounts of error by becoming stuck due to the expansion of the bottle under pressure. We fixed that before the Finals and used one wheel in the back that would not be affected by such expansion. Some smaller things we did were add and remove the rubber part of our wheels to reduce or increase friction but this also had affects on how straight it would run. For further improvement attention to the bottle and release methods would be the route of interest.