Title: Enthaply of combustion Aim: Determine the enthalpy of combustion for a mixture of alcohol and gasoline, and its effectiveness as a fuel. Determine the most effective proportion of alcohol and gasoline considering ethanol avoids the effects of global warming but gasoline has a greater enthalpy of combustion so the addition of ethanol to the mixture would make it have a Iower enthalpy of combustion. Introduction: Complete combustion of ethanol forms carbon dioxide and water vapor: [pic] [PiC] Complete combustio vapor.
The experiment has t the engine is designe ors to View nut*ge n dioxide and water It is only possible if pose. The ratio of gasoline to ethanol has to be significantly different; normally the proportion is 10% alcohol 90% gasoline. The experiment would not be possible if only ethanol was used. When analyzing the best proportion of each component take this into account. The benefit of using alcohol is that it reduces the amount of carbon dioxide produced during the combustion; hence it Will reduce global warming effects.
The proportion would greatest amount of ethanol is the best to avoid pollution and the effects of global warming but this does not guarantee it is going to be the mixture would the highest enthalpy of combustion. To Swipe to View nexr page To increase the benefits of the use of ethanol, ethanol could be acquired through fermentation. In this experiment ethanol was not acquired from fermentation but from a drugstore. Variables: Independent: amount of [pic]and [pic][pic] Dependent: energy, enthalpy of combustion Controlled: amount of water, heat loss Method: Procedure: -Weight a 250[pic]measuring cylinder. Using a measuring cyllnder of 200[pic] ofwater and place it in a beaker. Weight the beaker and the water. -Substract the mass of the beaker and the water from the value of the mass of the beaker to get the mass of water. A thermometer is placed in the beaker, record its initial temperature. -Cover the beaker with styrofoam to avoid heat lost to the surroundings. It has to be covered also on the upper part not only to avoid heat lost to the surroundings but to avoid evaporation and hence losing mass of water. -Measure the mass of a spirit burner including the wick. 8. 0 ml of gasoline and 2. 0 ml or ethanol are placed in the spirit burner. Record the new mass of the spirit burner. The percentage of ethanol is 10%. -The Wick on the spirit bumer is lit, burning the fuel, and heating the water. -The apparatus is placed in a glass box to avoid heat lost to the urroundings appreciable amount, below 800C to avoid water evaporating, the spirit burner is extinguished and the final temperature recorded The final quantity of fuel is measured and recorded after it had cooled down using an electric balance.
Final mass – Initial mass = Fuel that combusted. -Assume that 10% from the mass combusted is ethanol and 90% is gasoline. Using that the density of ethanol is O. 789 [pic] and knowing the volume calculate the mass. Then calculate the amount in moles of ethanol. Repeat the same for gasoline using that its density is 0. 75[pic]. Add both values and the result is the otal amount in moles of ethanol plus gasoline that reacted. -Calculate ener4,’ required to change temperature of water using the formula [pic] -Calculate the heat of combustion of ethanol -[pic].
The quantity in moles is the sum of the quantity of the moles of gasoline and ethanol that have been combusted. -Repeat the experiment using diferent proportions. Use 15% ethanol, 20% ethanol, 5% ethanol, 7%ethanol and 12% ethanol. Each experiment has to be performed at least three tmes. -Show a graph between the percentage of ethanol used and the enthalpy of combustion for the fuel Explain which of the proportions is the most effective. 31_1f3