By Cameron Oden, Shannon Cahill-Weisser,

and Melissa Simpson

CBE 101 8th Annual

Reaction Car Competition

Reaction ChemistryHydrogen Peroxide & Pyrolusite

Chemical Equation:H₂O₂ (aq) + MnO₂ (s) → H₂ (g) + O₂ (g) + MnO₂ (s)Pressure:(.020 L)(8 mol/L)(1 mol H₂O₂/1 mol H₂) = 0.08 moles H₂ & 0.08 moles O₂P = [(0.16 mol)(0.08205 L-atm/mol-k)(293 K)]/(.700 L) = 5.5 atm

We did not use this reaction because when we tested it, the gas was not produced quickly enough to be efficient for running the car.

Hydrochloric Acid & Baking SodaChemical Equation:HCl (aq) + NaHCO₃ (s) → NaCl (aq) + H₂O (l) + CO₂ (g)Pressure:(0.012 L)(12.1 mol/L)(1 mol HCl/1 mol CO₂) = .1452 moles CO₂P = [(.144 mol)(0.08205 L-atm/mol-K)(293 K)]/(.700 L) = 4.99 atm

We also added 12.5-13 mLs of water to help the reaction.

Car DesignWe ended up with a great

design, but to arrive there, we had to rebuild the entire car from scratch. (The old design would run only 15 feet at the

most)

Here’s a work in progress: very close to the final design.

Test Results

During our open lab time, while we tested different reaction ideas and

different car ideas, our data was very inconsistent. We found that a simple

change in the nozzle makes the difference between a car that curves vs.

a car that runs straight. We also discovered that miniscule changes in

amounts of water to our reaction impacted our results in a major way. With no water added, the car would travel ten feet at the most. When we

added 12mLs of water, on average, the car traveled about 21 feet, and with

13mLs of water, the car traveled close to 25 feet on average.

Open Lab Testing Semi-finals and Finals

Semi-finals (3rd Place) HCl

(mL)NaHCO3 (g)

H2O (mL)

Distance (ft) Comments

Semi-

Finals        

12 13 12.5 20'veered towards the right into

the grass      23' 7"        20'  

12 1312.7

5 19' 1"  12 13 13 ? kim wipe got stuck in nozzle      20' 2"  

     26' 10"  

FinalsHCl (mL)

NaHCO3 (g) H2O (mL)

Distance (ft)

Finals      12 13 12.5 22' 3''    13 26' 8''    12.75 24' 5''

NO SPEW!!!

Conclusions•During the semi-finals and finals section of this

project, our car performed very well. It was also fairly consistent. During the finals we

consistently ran between 22 and 27 feet.•We learned that changes in volumes of water as small as 0.5mLs can make a difference in

distance of around four feet.•At the end of this project, our car was at its best.•Without using different materials, we wouldn’t have been able to make the car more efficient or reliable.•For people who’s cars weren’t running efficiently, keep in mind: •Check the nozzle (cap)•Make sure the car is sturdy•Make sure the wheels are aligned