• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Investigation into the energy released by burning alcohols

Extracts from this document...

Introduction

Investigation into the energy released by burning alcohols Aim The aim of my experiment is to investigate how much energy is released by 5 different alcohols when they are burnt. These are Methanol, Ethanol, Propanol, Butanol and Pentanol. Scientific Theory In the following experiment I will be investigating how much energy is given off when you burn an alcohol. The 5 alcohols I will be investigating are methanol, ethanol, propanol, butanol and pentanol. All of these are part of the homologous series and so they all contain the functional group O-H. Their structures can be shown as follows: Therefore the general formula for alcohols is: When each of these fuels is burnt they are all exothermic, combustion reactions. A balanced combustion equation for methanol would be CH3OH + 11/2 O2 ? CO2 + 2H2O. A combustion reaction is when the fuel burns in the oxygen in the air producing carbon dioxide and water. The combustion equation can be used to work out the energy given off by using bond calculations. The reactions are exothermic because they give off energy to the surroundings and so the energy released that I work out will be a negative number. ...read more.

Middle

book and have found the same thing: Methanol: -726.0kJ/mol Ethanol: -1367.3kJ/mol Propanol: -2021.0kJ/mol Butanol: -2675.6kJ/mol Pentanol: -3328.7kJ/mol Finally, I can do bond calculations to see a specific pattern. The energies for each bond used are shown below in kJ/mol: C-H: 413 C-C: 347 C=O: 805 C-O:358 O=O:498 O-H: 464 I then did the calculations for each alcohol using these bond energies. An example is for Methanol: CH3OH +11/2O2 ? CO2 + 2H2O 2061 + 747 1610 + 1856 2028 - 3466 = Preliminary Work In my preliminary work I burnt butanol to see what sort of number I would get and to ensure the equation would work. The final answer was -695.8KJ/mol. I now know that I will find my results are around this number and that most of them will be smaller than this. Initially I was planning to burn each fuel for a length of 2 minutes and look at the temperature change but I will not do this because the concept of time in the equation is irrelevant. Instead, I will now keep the temperature change constant and ignore the time. In my preliminary experiment I found out a lot of things, which I need to do make my experiment better. ...read more.

Conclusion

Variables There are many things that I will have to do to ensure that my experiment is a fair test. I will only change one factor and that will be the fuel that is been burnt. * For each test the temperature change will be 30 C. This means the water will rise from a temperature of 20 C to 50 C in each test. * I will repeat each test three times so I can obtain three sets of results for each alcohol and then take an average. This also makes it possible to see any anomalies * The calorimeter will always be 2cm above the top of the wick of the burner for each test so that the same amount of heat is transferred in each test. * In each test I will fill the calorimeter with 50cm3 of water. * The thermometer in each test will be suspended in the calorimeter using a clamp on the clamp stand. * After each test I will clean down the bottom of the calorimeter of any soot that has built up as this could affect the conductivity of the calorimeter in the next test. * * * * ?? ?? ?? ?? Claudia Spink 10MJ ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Organic Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Organic Chemistry essays

  1. An Investigation to see how the energy released by burning Alcohols depends on the ...

    Each successive alcohol contains one more carbon atom than the one before. It also has 2 more carbon-hydrogen bonds and 1 more carbon-carbon bond. So obviously as the amount of carbon atoms in an alcohol increases, so will the amount of energy released.

  2. The Energy Content Of Different Fuels

    Mass of fuel used = (236-233.5) = 2.5g 3. Molar mass of C2H5OH = 46 No. of moles = mass Molar mass No. of moles = 2.5 / 46 = 0.054347826 moles of fuel used 4. Energy used & produced to = mass of water X S.H.C X Temp rise heat the water Energy = 25 X 4.2 X 69 = 7245 joules 5.

  1. Methanol - Bond Energy Calculations

    Lastly, the watch glass gives the flame a large surface area, so as to heat the water in a more concentrated fashion, it is also easier to observe the flame and light it safely. The experiment for each fuel shall be carried out three times so as to give me an average result.

  2. The energy produced of different alcohols.

    I noticed that the more carbon atoms in the alcohol the more heat it produces within the five minutes of readings. Looking at the sequence of the number of carbons in the alcohol, from the least, methanol, to ethanol, to propanol, to butanol, and to hexanol, is in order of

  1. Investigating the energy released from burning different alcohols.

    As the molecules of the alcohols increase in size, the activation energy will increase also as there're more bonds to break. But in addition there will be more bonds formed from the reaction. Though increase in the number of bonds broken will be the same as the increase in the

  2. Molar Heat of Combustion of Alcohols

    relatively similar but for Propanol our result was just over a third of the theoretical value. Inconsistencies like this are expected in this type of test because of the amount of energy being lost all of the time. Analysis of My Results: For this type of test huge inconsistencies are expected throughout the data, our results reflect this.

  1. "Could Sainsbury's add value to their business by using an alternative fuel for their ...

    * Promote switch to Natural Gas * Van fleet livery * Carrier bags * Television ads 7.6 Evaluation: Due to the subjectivity involved in customer perception, it is difficult to predict exactly how any customer base will react to new marketing strategies.

  2. GCSE Chemistry Revision Notes - everything!

    Detergents 3. Dyes 4. Ceramics 1. Hydrogen 1. As fuel in hydrogen fuel cells 2. To harden vegetable oils to make margarine. 3. To make hydrogen peroxide Hydrocarbons Hydrocarbons are compounds of carbon and hydrogen only. There are two common families of hydrocarbons, the alkanes and the alkenes.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work