Abstract
The aim of this article is to present the search of a mathematical relation between the amount of reagents and the internal pressure on PET bottle rockets suitable to the level IV of the Brazilian Rocket Exhibition. Initially, it was described the dioxide carbon produced by the chemical reaction between the vinegar and the sodium bicarbonate through Clausius-Clapeyron equation. The predicted results from this approach didn't match from those obtained experimentally. Subsequently, it was adopted the van der Waals gas equation to describe the gas behavior. According to this wide study, it was observed that the last approach is able to describe the pressure behavior in the regime between 0 – 60PSI. Above 60PSI none of the theoretical purposes were able to describe the internal pressure behavior. Consequently, it was understood that the increasing of internal pressure moves the chemical equilibrium to the side of reagents (Le Chatelier's Principle) and it was concluded that is possible to obtain an empirical relation between the pressure and amount of reagents, if it is assumed an attenuation pressure dependent factor in the mols number produced by the chemical reaction. This study can be implemented as an integration resource of the contents approached in high school mainly Physics and Chemistry.
Keywords:
PET Bottle Rockets; Clausius-Clapeyron equation; van der Waals gas equation
