Investigation of the heat energy produced by combustion of various Alcohols Aim: ---- To investigate how different alcohols produce different amounts of heat energy through combustion. I will be heating water using different alcohols as fuels and measuring the amount of fuel consumed. From working out how much fuel has been used I can work out how much bond energy has released from the molecules of the alcohol. From those results I will be able to say which alcohol is the best for combustion and which one is the worst to combust. · A good fuel should produce a lot of heat energy and use a small amount of fuel. (economical) · A bad fuel uses a lot of fuel and produces less heat energy. (non-economical) E=mc E= Energy M= mass of water C= Specific heat = Difference in temperature Using this equation I will be able to find out which fuel gives out the most heat energy and use the least amount of fuel. Variables --------- During the experiments the water will be heated using different spirit burners containing different alcohols. I will be able to change different parts of the experiment. These are: · Volume of water heated: Depending on how much water we use depends on how long it takes to heat up. If we heat a large volume of water it will take it longer to heat up, as there will be more molecules for the heat from the spirit burner to give energy to, it will take longer for the water molecules to get enough energy to loosen and break, so the reaction will be slower. If we only use a small volume of water the heat energy from the spirit burner will give the water molecules energy faster as there are will less of them so more heat energy per molecule, this means the bonds will loosen and break quicker so the reaction will be faster. · Distance between spirit burner and Copper Calorimeter: The further the copper calorimeter is from the heat source the more heat will be lost into the surrounding atmosphere and not directed towards the water and the slower the reaction will be. If the pot is close to the heat source, more heat is directed to the water so will be heated faster. · The Alcohols: Different alcohols have different bond structures, some bonds needing more energy to break them than others, and some releasing more energy when they are broken. · Temperature increase: I could change the amount the temperature has to rise before I record my results. This will only effect the amount of fuel used, so hasn’t got much relevance to the experiment.
The Difference in Energy Release of Various Alcohols In this experiment, I plan to find out the difference in energy release between different sorts of alcohols. To do this I will test how much alcohol is required to increase the temperature of 100ml of water by 30 degrees Celsius. Obviously, many factors may affect my results, therefore making them less reliable. To improve my results, I will carry out some preliminary research to see if I can improve the reliability and accuracy. Please see attached preliminary work for details (sheet 2a).
The U.S. Department of Energy projects that if a mere 10% of automobiles nationwide were powered by fuel cells, regulated air pllutants would be cut by one million tons a year and 60 million tons of the greenhouse gas carbon dioxide would be eliminated. DOE projects that the same number of fuel cell cars would cut oil imports by 800,000 barrels a day which is about 13 percent of total imports.
The alcohols I will use are; methanol, ethanol, propanol, butanol and octanol. It is important that I use five alcohols so that there are enough results to spot any patterns. The experiments are to be done three times so that an average can be taken this will make the results more reliable because any anomalous results will have less affect on the overall findings. The first four of the alcohols listed above have carbon chains with 1,2,3 and 4 Carbons. I chose to use these alcohols with an increasing number of carbon atoms in their carbon chains.
Barry, Patrick. "Thinning Fuel Before Injection Boosts Efficiency." Science News 174.9 (2008): 9. Academic Search Premier. Web. 26 Nov. 2011.
one gram of water by 1ºC. I chose to use water because it is safe,
how much gas is sold is how efficient the particular automobile uses gas and what
Specific heat capacity of aqueous solution (taken as water = 4.18 J.g-1.K-1). T = Temperature change (oK). We can thus determine the enthalpy changes of reaction 1 and reaction 2 using the mean (14) of the data obtained. Reaction 1: H = 50 x 4.18 x -2.12.
cm∆T where c is the specific heating capacity of water (4.17 Jg-1K-1) -m is the mass of water, in g -∆T is the change of temperature of the water Apparatus Apparatus I will use Size of the apparatus Value /quantity distill water / >3 litres, as much as possible* thermometer 0-110C thermometer 1 measuring cylinder 100 cm3 1 electronic balance correct to 2 decimal places 1 Bunsen burner / 1 draught shielding each approx. 20cm x 20cm 5 metal calorimeter *** 4 clamp about 1 meter 6 spirit burner with wick / 4 match/wooden stick / as many as possible burner cap / 4 tile as big as possible 1 Propan-1-ol / half filled the spirit burner * Butan-1-ol / half filled the spirit burner * Butan-2-ol / half filled the spirit burne * Cyclohexanol / half filled the spirit burner * ***-I will find out in preliminary test *-Half filled the spirit burner because alcohol should be away from
Tf-Ti). Next, subtract the initial temperature, 25 degrees from the final temperature, 29 degrees putting the change in temperature at 4 °C. To calculate the heat absorbed by the water in calorimeter, use the formula (q = mCΔT). Plug in 50 mL for (m), 4.184 J for (C) and 4 °C for the initial temperature (ΔT), then multiply.
Then, repeat steps 7-11 another 4 times but with the room temperature water. For the room temperature water just leave it in the room but try not to change the room’s temperature. 15. Try to put all your recorded data into a table for organization 16. Repeat the entire experiment for more reliable data.
The increase in temperature will therefore increase the rate of reaction. As this is the variable I am measuring I will not keep the temperature constant and therefore I will be varying it. Volume of water- if the volume of the water is increased there is more likelihood that there will be more collisions.
This software enables you to simulate experiments. This means that I am able to quickly carry out experiments to help in planning for my investigation. ---------------------------------------------------------------------- Alcohol Temperature Increase (oC) Mass of burner before exp. (g) Mass of burner after exp.
- Temperature was measured after and exact time i.e. 1 minute, 2 minutes, 3 minutes.
This is expressed as Δ +ve (delta positive). If the total energy put in is less than the energy created, then the substance warms up (it is exothermic). This is expressed as Δ -ve (delta negative). I will investigate eight different alcohols using an alcohol or spirit burner, to measure the energy change during burning by measuring the change in temperature of some water held in a container.
Investigation to Find the Relative Energy Release of Five Alcohols: Ethanol, Methanol, Propanol, Butanol and Propanol