Event 3: Chemical Engineering

Chem-E-Car

River Dell High School Team A (RDHSA) Celyne Moh Daniel Ross Ronald Vertsman

Objective “Design and construct a car that is powered with a chemical energy source that will travel a given distance and stop. ” • Commercial batteries (for example, AA batteries) are allowed as the power source if a controlled chemical reaction is used elsewhere in the car’s system (as a stopping mechanism, for example).

Concept • Iodine clock reaction • Using a light and photo-sensor to control a motor

Kinetics Iodine clock:

Step 1: IO 3 − (aq) + 3 HSO 3 − (aq)



I − (aq) + 3SO 4 2− (aq) + 3H + (aq) Step 2: IO 3 − (aq) + 5 I − (aq) + 6 H + (aq)



3 I 2 (aq) + 3 H 2 O (l) Step 3: I 2 (aq) + starch



{a dark blue iodine/starch complex} Rate = k[NaHSO 3 ] 2 [KIO 3 ] 1 k = 188.04

Allocation of Budget

Item 100g Potassium Iodate 500g Sodium Bisulfite 500g Starch, Reagent Soluble AAA batteries (20 Batteries) Distilled Water (3 Bottles) Total Price $17.01

$9.70

$55.60

$7.07

$2.64

$92.02

Construction • Old RC car • Plexiglas© • Copper wiring • Fiberglass Cylinder • Batteries • Circuitry

Circuitry

Kinematics • • Photo-sensor Colors of solutions Distance Traveled = velocity x time The proper concentrations for the reactants is determined so the car travels a given distance.

Conclusion • Car veers too much o Axle • Time of trial varies = distance varies o Concentration of solutions o o Human Error Splashing

Reconstruction (2 nd model) • Car veering o o Replace axle Replace wheels • Varying distances o countdown

Observations (2 nd model) • Car veered less • Car ran varying distances

Results (2 nd model) 40 35 30 25 20 15 14 15 16 17 18

mL NaHSO 3

19 20 21

Conclusion (2 nd model) • Car Veering o The axle • Varying distances o o Momentum Countdown

Reconstruction (3 rd model) • Front wheel • Reduce concentration of solutions • Change variable reactant • Cork • Syringe

Observations (3 rd model) • Car runs straight • Trials are more precise • Trials are more accurate • Solutions are not spilling

Final Conclusion • Car stops within 5ft of destination • Car runs too fast for complete accuracy

Questions?