The purpose of this experiment was to compare biodiesel to other fuels. The ecotoxicity of biodiesel was estimated, along with that of other biofuels through the germination of seeds in the presence of different concentrations of fuels. This resulted in biodiesel having an average of 79.4% germinated seeds in a 10% solution of fuel, compared to other fuels whose percentage of germinated seeds decreased with higher concentrations of fuel. In addition, biodiesel was also synthesized and its heat of combustion was found through the use of calorimetry. The heat capacity for the calorimeter was based on the heat of combustion for ethanol, which was then used to determine the heat of combustion for biodiesel. The average heat of combustion for biodiesel was ∆Hcomb= -13090.83 kJ/mole, as opposed to the theoretical value of -11496.6 kJ/mole, which resulted in a 13.9% difference. Furthermore, taking into consideration the ecotoxicity of biodiesel, its effect on the environment, and fuel efficiency, biodiesel proved to be the more favorable fuel relative to the other fuels tested. The goal of the experiment was to compare and determine the advantages of using biodiesel as a fuel as opposed to other fuels.
In addition to stating the goals and approach of the lab, make sure to mention which factors you are using to evaluate which fuel is "better". Summarize main results (give actual values of the things you calculated--where applicable, give averages of trials, not all trials).
In order to compare biodiesel to other fuels, its properties were compared to that of other fuels to obtain relevant information regarding the impact of a fuel on the environment, the efficiency of a certain fuel when burned, and the amount of energy produced by the combustion reactions of the fuels. While many different biofuels are capable of being used to power vehicles, factories, and other necessary processes, their sources are being depleted while the environment undergoes increasingly detrimental effects. The growing demand for fuel is on the rise; however, pollutants that arise from both burned and unburned hydrocarbons and nitrogen oxides are ozone or smog forming precursors1. This causes factors such as harmfulness of emissions, cost of production, and efficiency to become more of an importance when determining which fuel to be used. During the experiments that were conducted, biodiesel was compared to other fuels to determine the advantages of biodiesel as a source of fuel in respect to other fuels. One advantage is the ecotoxicity of biodiesel and other fuels shown through the seed germination experiment, which was a reliable indicator of a fuel’s effect on the environment. Biodiesel is a fuel that can be synthesized from vegetable oil, having byproducts that are not harmful to the environment, indicating that it is a fuel of low ecotoxicity. Synthesis of biodiesel is shown in the chemical reaction below:
C57H100O6 + 3CH4O → 3C19H34O2 + C3H8O3
Soybean oil (a substance with low ecotoxicity) is combined with a solution of methanol and NaOH, which produces biodiesel and glycerol (also of low ecotoxicity). Since biodiesel is able to be extracted simply through the heating and addition of a methanol and NaOH solution, the synthesis of biodiesel compared to other fuels is a more simple and preferable process. If biodiesel is a fuel of low ecotoxicity, then its lack of impact on the environment combined with its ability to burn efficiently show that it is a good quality source of fuel. However, a low ecotoxicity alone does not necessarily mean that biodiesel is an efficient fuel. The heat of combustion of biodiesel must be taken into consideration as well—this indicates the amount of heat energy that is released when a substance is burned. This can be done through a calorimetry, a technique that measures the amount of heat produced by the combustion reaction. Calorimetry is performed with a calorimeter, which is...
References: Laboratory Manual: Chemistry 1A Fall 2011. Department of Chemistry; University of California, Berkeley. Regents of the University of California, 2011.
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