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Recently in the news, there have been discussions of the rise of ethanol gas prices and other forms of natural fuels.
Every year, engineers around the nation participate in a competition to
not only research and apply new forms of powering cars, but also to
apply their engineering skills. Each spring, the American Institute of Chemical Engineers (AIChE) holds
their regional conferences and car competitions. There are nine
regional conferences held in the United States. This year Manhattan
College traveled to Bucknell University for the Mid-Atlantic car
competition with a team of eight in hopes of qualifying for Nationals
in the fall.
The competition is based on the design, safety, and ability of the car. The cars are usually the size of a shoebox; toy cars can be used or new cars can be built. The car must be able to travel a certain distance, between 50 and 100 feet, while carrying a certain weight, between 0 and 500 milliliters of water. The distance and the weight are not known until the teams are about to compete. Therefore, the car must be able to perform under any of the given conditions. The car is tested and calibrated even before the teams leave for the competition. The car must be powered by a chemical reaction and also be stopped by a chemical reaction. The teams are not allowed to use a combustion reaction. Typically a fuel cell, chemical battery, or pressure propulsion system are used. This year's team decided on a Copper-Magnesium chemical battery for the car.
A battery converts chemical energy directly to electrical energy. This battery consists of a voltaic cell, which is composed of two half cells connected in series by the conductive electrolyte. The cell has a positive electrode, the cathode, and a negative electrode, the anode. Copper was used as the cathode, while magnesium was used as the anode. The cathode and the anode do not touch each other, but are immersed in a liquid electrolyte. The voltage produced by a cell is dependent on the chemicals that are used. Different chemicals have different electrochemical potentials. Copper-Magnesium batteries are able to produce 1.5 volts.
As shown in Figure 1, the entire battery is placed in a plastic container and a rolled copper plate sits in a solution of copper sulfate,which all sits in dialysis tubing. The dialysis tubing is used as a resistor, which allows the flow of electrons, but slowly. A magnesium ribbon sits around the dialysis tubing and the plastic container holds the dialysis tubing, the magnesium ribbon, and magnesium sulfate. On one side magnesium metal will be oxidized to magnesium sulfate, and on the other side copper sulfate will be reduced to copper metal. As the magnesium reacts, it forms an oxide coating which then hinders the magnesium from conducting.
The car must also be stopped by a chemical reaction. The team decided on a "stopping mechanism" that would consist of magnesium integrated into the circuit. Right before the car would be started, the magnesium would be placed in a beaker of hydrochloric acid. Once the magnesium is submersed in the acid, it will begin to react and dissolve which will then break the circuit. See Figure 2. Through experimental data and trial and error, it was determined that concentrations between 0.9 M and 1.1 M would be used. For example, if the car needed to travel 85 feet carrying 375 milliliters of water, the concentration would be about 0.9 M.
Mg + 2HCl → MgCl(2) + H2
In recent years, cars are being held to a higher standard of safety. After numerous mishaps, such as pressure cars exploding and acid being spilt, AIChE raised their standard of safety for the car competition. Job Safety Analysis's (JSA's) are used so that judges and committee members are able to decide if a car is safe enough to run in the competition. In addition to the JSA's, each school had to attend a six hour course on process safety. Manhattan's car was completely designed with safety in mind. The entire system sat atop an RC car in a rectangular tupperware, stabilized by pylons attached to the base of the car. Within the tupperware sat the battery cell and the "stopping mechanism", each within their own containers to prevent spilling. The tupperware was then packed with non-reactive foam to prevent any of the components from moving along with a 500 milliliter bottle to carry the water.
Once the car is approved for its design and safety factors, the car is able to compete. The car starts with its front end touching the designated starting line. The distance is measured from the front most point of the car. The goal of the competition is to have the car stop closest to the specified finish line (in bounds) carrying the specified load. The course is wedge-shaped with a starting line and the prescribed distance clearly marked in an arc of constant distance from the starting point. A vehicle that goes outside the course will have its distance measured where it went out of bounds. When measuring the distance from the finish line it does not matter if the car goes longer or shorter than the prescribed distance.
At the regional competition, the teams compete for qualification to the national competition. The first five teams to get closest to the finish line qualify for Nationals along with a cash prize for first and second place. This competition provides chemical engineering students with the opportunity to participate in a team-oriented, hands-on design, and construction of a small chemical powered model car. It encourages students to become actively involved in their professional society along with an opportunity to increase awareness of the chemical engineering discipline among the general public, industry leaders, educators and other students.
The competition is based on the design, safety, and ability of the car. The cars are usually the size of a shoebox; toy cars can be used or new cars can be built. The car must be able to travel a certain distance, between 50 and 100 feet, while carrying a certain weight, between 0 and 500 milliliters of water. The distance and the weight are not known until the teams are about to compete. Therefore, the car must be able to perform under any of the given conditions. The car is tested and calibrated even before the teams leave for the competition. The car must be powered by a chemical reaction and also be stopped by a chemical reaction. The teams are not allowed to use a combustion reaction. Typically a fuel cell, chemical battery, or pressure propulsion system are used. This year's team decided on a Copper-Magnesium chemical battery for the car.
A battery converts chemical energy directly to electrical energy. This battery consists of a voltaic cell, which is composed of two half cells connected in series by the conductive electrolyte. The cell has a positive electrode, the cathode, and a negative electrode, the anode. Copper was used as the cathode, while magnesium was used as the anode. The cathode and the anode do not touch each other, but are immersed in a liquid electrolyte. The voltage produced by a cell is dependent on the chemicals that are used. Different chemicals have different electrochemical potentials. Copper-Magnesium batteries are able to produce 1.5 volts.
Cu (II) + 2Mg → 2Mg (I) + Cu + 1.5 volts
As shown in Figure 1, the entire battery is placed in a plastic container and a rolled copper plate sits in a solution of copper sulfate,which all sits in dialysis tubing. The dialysis tubing is used as a resistor, which allows the flow of electrons, but slowly. A magnesium ribbon sits around the dialysis tubing and the plastic container holds the dialysis tubing, the magnesium ribbon, and magnesium sulfate. On one side magnesium metal will be oxidized to magnesium sulfate, and on the other side copper sulfate will be reduced to copper metal. As the magnesium reacts, it forms an oxide coating which then hinders the magnesium from conducting.
The car must also be stopped by a chemical reaction. The team decided on a "stopping mechanism" that would consist of magnesium integrated into the circuit. Right before the car would be started, the magnesium would be placed in a beaker of hydrochloric acid. Once the magnesium is submersed in the acid, it will begin to react and dissolve which will then break the circuit. See Figure 2. Through experimental data and trial and error, it was determined that concentrations between 0.9 M and 1.1 M would be used. For example, if the car needed to travel 85 feet carrying 375 milliliters of water, the concentration would be about 0.9 M.
Mg + 2HCl → MgCl(2) + H2
In recent years, cars are being held to a higher standard of safety. After numerous mishaps, such as pressure cars exploding and acid being spilt, AIChE raised their standard of safety for the car competition. Job Safety Analysis's (JSA's) are used so that judges and committee members are able to decide if a car is safe enough to run in the competition. In addition to the JSA's, each school had to attend a six hour course on process safety. Manhattan's car was completely designed with safety in mind. The entire system sat atop an RC car in a rectangular tupperware, stabilized by pylons attached to the base of the car. Within the tupperware sat the battery cell and the "stopping mechanism", each within their own containers to prevent spilling. The tupperware was then packed with non-reactive foam to prevent any of the components from moving along with a 500 milliliter bottle to carry the water.
Once the car is approved for its design and safety factors, the car is able to compete. The car starts with its front end touching the designated starting line. The distance is measured from the front most point of the car. The goal of the competition is to have the car stop closest to the specified finish line (in bounds) carrying the specified load. The course is wedge-shaped with a starting line and the prescribed distance clearly marked in an arc of constant distance from the starting point. A vehicle that goes outside the course will have its distance measured where it went out of bounds. When measuring the distance from the finish line it does not matter if the car goes longer or shorter than the prescribed distance.
At the regional competition, the teams compete for qualification to the national competition. The first five teams to get closest to the finish line qualify for Nationals along with a cash prize for first and second place. This competition provides chemical engineering students with the opportunity to participate in a team-oriented, hands-on design, and construction of a small chemical powered model car. It encourages students to become actively involved in their professional society along with an opportunity to increase awareness of the chemical engineering discipline among the general public, industry leaders, educators and other students.
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