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

Fuels Coursework Plan

Extracts from this document...

Introduction

Comparing the Enthalpy change of combustion of different alcohols Saidul Amin 12LT Combustion reactions are exothermic. The chemical reactants loose energy and the products end up with less energy than the reactants had. Enthalpy change is the measurement of energy transferred to and from the surroundings. Enthalpy change is worked out as: ?H= H products - H reactants The diagram below shows an enthalpy level diagram for an exothermic reaction. I will expect all my enthalpy change values to be negative as combustion is an exothermic reaction, and therefore energy is being lost to the surroundings. It is however obvious that these values will change for different alcohols, as their molecular structures are different. There are three independent variables which can be investigated in this experiment and these are chain length of the alcohol, amount of branches there are in the alcohols and also the position of the functional group on the alcohol. In this experiment I will be seeing how the chain length of different alcohols affects change in enthalpy. In turn this means that I am testing how an increased number of carbon atoms on the alcohol effects change in enthalpy. Therefore I will be using alcohols with different number of carbon atoms, and these will be Methanol, then Ethanol, Propan-1-ol and Butan-1-ol. I will then combust these alcohols and see what values they give for enthalpy changes, and then I will go on to comparing them. ...read more.

Middle

Methanol CH3OH Ethanol C2H5OH Propan-1-ol C3H7OH Butan-1-ol C4H9OH For the extension experiment I will be using Propan-1-ol, Propan-2-ol, Butan-1-ol and Butan-2-ol. Propan-2-ol C2H8O- Safety glasses must be worn. Same measures of first aid as ethanol. Butan-2-ol C4H10O- To use this fuel safety glasses must also be worn and it must be used in a well ventilated area. Same measures of first aid as methanol. Equipment Copper Calorimeter Heatproof mat Accurate balance (2.d.p) Funnel - to avoid spillages which may be dangerous when close to lit fuel burners Thermometer (0.1 �C divisions) Heat shield Clamp stand Measuring Cylinder Glass rod Alcohol (fuels in burners, at least 200g of each) -Methanol -Ethanol -Propan-1-ol -Butan-1-ol Bunsen burner Splint Lab coat Distilled Water Goggles Diagram Precision and Accuracy I will work carefully as I do these investigations, not only for health and safety issues, but also for accuracy and precision. I will use all apparatus correctly as far as my understanding of them allows me to, which will make my measurements as precise as possible. This means that my repeats should almost be the same as my results, and if not they should be very close. They should also be to such an extent of accuracy that anyone else using the same procedure was to do it then results should virtually be identical. Therefore this will indicate the reliability of my measurements. ...read more.

Conclusion

0.52 1075.85 Rpt 2 100.00 21.00 39.00 18.00 184.38 183.88 0.50 1118.88 Average KJ mol-1 1104.54 Butan-2-ol 100.00 21.00 39.00 18.00 153.57 153.03 0.54 1036.00 Rpt 1 100.00 21.00 39.00 18.00 153.03 152.53 0.50 1118.88 Rpt 2 100.00 21.00 39.00 18.00 152.53 152.00 0.53 1055.55 Average KJ mol-1 1070.14 Theoretical calculations of Enthalpy Change By using the bond enthalpy values (from the data tables), the enthalpy change of combustion can be calculated theoretically. For example Methanol + Oxygen Carbon dioxide + Water CH2OH (g) + 1.5 O2 CO2 + 2H2O C-H 413 kJmol-1 C-O 336 kJmol-1 2 x C=O 2 x O-H O-H 464 kJmol-1 O=O 498.3 kJmol -1 C=O 805 kJmol-1 3x C-H 1x C-O + 1.5 x O=O 1x O-H 2039 kJ + 747.45 kJ 1610 kJ + 1856 kJ 2786.45 - 3466.00 Enthalpy change of combustion of methanol = -679.55 kJmol-1 It is apparent that my result differs to that of the data sheets, which shows that the Enthalpy change of combustion of methanol is -726 kJmol-1. This is because the value given in the data sheets is the enthalpy change of combustion of methanol in standard conditions, but also the fact that the exact bond enthalpies depend on the different compounds used to obtain the bond enthalpy. After having worked out all the calculations, I can then produce my final results for my experiment like this: Fuel Enthalpy change of combustion (kJ mol-1) Methanol Ethanol Rest of fuels... ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level 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 AS and A Level Organic Chemistry essays

  1. Marked by a teacher

    Preparation of propanone from propan-2-ol

    5 star(s)

    There might be some product that stayed with the calcium chloride granules after pouring the product out which led to a loss of product. 2. There were side reactions and incomplete reactions. First, the reaction might also be incomplete as in this reaction, it was quite hard to distinguish whether

  2. Peer reviewed

    An investigation into the efficiency of alcohols as fuels.

    5 star(s)

    -1346 -2021 -2006 3138 These calculated results will be used for comparison with the results obtained through experimentation. As the change in alcoholic structure is set, so is the change in enthalpy between them. Below explains how this change was calculated using bond theory with the structure of the alcohols

  1. The aim of this experiment is to investigate the enthalpy change of combustion for ...

    m is the change in mass, c is the heat capacity of water which is known as 4.18 and t is the change in temperature.) * Repeat experiment twice more for each alcohol and calculate the enthalpy of combustion for each and then take an average.

  2. F336- aspirin individual Investigation

    First I add a known mass of our manufactured aspirin to a 250 cm3 volumetric flask and then add 25 cm3 of sodium hydroxide and heat to hydrolyse the aspirin and I then add water to the 250 cm3 mark I then pipette 25 cm3 of the hydrolysed aspirins solution

  1. Find the enthalpy change of combustion of a number of alcohol's' so that you ...

    Notably draughts could have a catastrophic effect on the factor of efficient heat transfer and could be detrimental to the outcome of the results. This is why I have placed 4 heat mats around the experiment. Loss of the alcohol itself due to evaporation has also been carefully considered.

  2. The aim of this experiment is to produce Aspirin. This is an estrification in ...

    This suggests that the re-crystallised aspirin is pre with very little impurities. However if impurities are present, forward titration will neutralise acetylsalicylic acid and the impurities as well. Also using this titration it was difficult to identify the end point because aspirin is a weak acid and the reaction takes place very slowly.

  1. Compare the enthalpy changes of combustion of different alcohols

    When the apparatus is set up according to the diagram, the testing can begin. The calorimeter consists of a copper can, I will use this instead of a bomb calorimeter which would ensure the alcohol is burned under standardised conditions.

  2. Evaluate the most suitable vegetable oil for conversion into a biodiesel fuel.

    Additionally it requires significantly less energy to break the double bonds, which will result in a higher chance of error in the conversion process. Other options such as Linseed and Sunflower oil would also be unsuitable as they too contain a large percentage of polyunsaturated acids.

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