1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  • Level: GCSE
  • Subject: Science
  • Document length: 971 words

An experiment for comparing the enthalpy change of combustion of different alcohols.

Extracts from this document...


An experiment for comparing the enthalpy change of combustion of different alcohols Aim To find out the enthalpy change of combustion for a number of alcohols. Apparatus Thermometer Measuring cylinder Electrical balance Stand Burners of different alcohols (methanol ethanol propan-1-ol butan-1-ol) Water Copper can Clamp Boss Heatproof mal Matches Method 1.Measure 200cm of water (at room temperature) into the measuring cylinder; record the temperature of the water. 2.Set up the apparatus as shown below in fig 1: Thermometer Stand Copper can Thermometer Boss & clamp Copper Can Stand Alcohol burner Heatproof Fig 1. The apparatus to measure enthalpy change 3.Pour the water from the measuring cylinder into the copper can, which is on the stand and clamped in position, and put a thermometer into the water to measure the temperature change. 4.Weigh the alcohols that are to be investigated, and record the weight. 5.Place the alcohol burner under the copper can, which is on the stand. 6.Ignite the burner with a match to heat the copper can, which contains water. more.


The steps described in the method are detailed and clear and progress from setting up the experiment to obtaining results. Result tables This is the result table of the weight of the alcohols used for rising up 20C of water (from 21C to 41C) Methanol Ethanol Propan-1-ol Butan-1-ol Beginning weight of the alcohols 232.39g 231.41g 248.30g 247.46g Finishing weight of the alcohols 231.16g 230.51g 247.49g 246.77g Alcohol used 1.23g 0.90g 0.81g 0.69g This is the result table of the changing in temperature Methanol Ethanol Propan-1-ol Butan-1-ol Beginning temperature 20ºC 21ºC 21ºC 22ºC Finishing temperature 40ºC 41ºC 41ºC 42ºC Temperature change 20ºC 20ºC 20ºC 20ºC Calculations The beginning temperature is 21C 4.17 X 200 X 20 = 16680J=16.68KJ Methanol: Hc = 16.68 X 32 / 1.23 = 433.95kJ/mol-1 The Hc of methanol is 433.95KJ/mol-1 Ethanol: Hc = 16.68 X 46 / 0.90 = 852.53KJ/mol-1 The Hc of ethanol is 852.53KJ/mol-1 Propan-1-ol: Hc =16.68 X 60 / 0.81 = 1235.56KJ/mol-1 The Hc of propan-1-ol is 1235.56KJ/mol-1 Butan-1-ol: Hc = 16.68 X 74/0.69 = 1788.87KJ/mol-1 The Hc of butan-1-ol is 1788.87/KJmol-1 Procedural errors The official values of the energy produce by methanol, more.


+/- 0.005 / 230.51 x100 % = 0.0021 % Mass of the propan-1-ol burner (reading): Before the combustion +/- 0.005 / 248.30 x100 % = 0.0020 % After the combustion +/- 0.005 / 247.49 x100 % = 0.0020 % Mass of the butan-1-ol burner (reading): Before the combustion +/- 0.005 / 247.46 x100 % = 0.0020 % After the combustion +/- 0.005 / 246.77 x100 % = 0.0020 % Measuring cylinder: +/- 0.5 / 200 X 100 % = 0.25 % Temperature: +/- 0.5 / 20.0 X 100 % = 2.5 % Conclusion The generalized equation for the combustion of alcohols is: Alcohol + Oxygen Carbon dioxide + Water The longer chain molecules such as butan-1-ol and propan-1-ol can produce more energy than shorter chain molecules like methanol and ethanol, because the energy is contained in the bonds, Therefore an alcohol with the greatest number of carbons will have greatest amount of energy, and will produce the increase in temperature for the least amount of fuel used. Reference Heinemann, Salters Advanced Chemistry, Chemical idea (Second Edition), Central Team George, Burton, John Holman, John Lazonby, Gwen Pilling and David Waddington 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. GCSE Chemistry Revision Notes - everything!

    The Transition metals They are all typical metallic elements. They are good conductors of heat and electricity, workable, strong and mostly high densities. Apart from mercury, they all have reasonably high to very high melting points. They are much less reactive than Groups 1 and 2, and donât react as rapidly with air or water.

  2. Measuring the Enthalpy Change of Combustion of Different Fuels

    Butan-1-ol (4.2 Jg-1K-1) x (100 grams) x (20.5° C) energy transferred= 8610 J 8610 J = 8.61 kJ mass of fuel used = 0.46 grams molar mass of propan-1-ol = 74.00 grams 0.46 grams/ 74.00 grams = 0.00621621 grams = 0.006 grams ?Hc = 8.61 kJ/0.006 grams = 1435.000

  1. Titration experiment - write up

    It must remain constant to make it a fair test.) 15) Place the conical flask on the stand so that the tip of the burette slightly enters the neck of the conical flask. Then place the white tile underneath the conical flask.(so that a colour change can be recognised more easily)

  2. Comparing the enthalpy changes of combustion of different alcohols.

    Irritates the skin and is harmful if swallowed * Care must be taken with the thermometer. * Take care not to touch the calorimeter immediately after the experiment, as it will be hot. * Keep the wick length small or the flame will be very high.

  1. Comparing the Enthalpy Changes of Combustion of Different Alcohols

    * Using the thermometer stir the water until the temperature of the water has risen by approximately 15?C more than the original temperature of the water in the metal calorimeter. * Make sure that as soon as the water is about to reach +15?C that you are ready to douse

  2. Molar Heat of Combustion of Alcohols

    We can work out the average enthalpies by dividing each result by three: 1736/3=579 2179/3=726 4726/3=1575 Bond Enthalpy Values for the Three Alcohols Ethanol Ethanol + Oxygen = Carbon Dioxide + Water C2H5OH + 3O2 = 2CO2 + 3H2O The Bonds Broken In the Reaction: 3*O=O 3*498=1494 5*C-H 5*413=2065 1*C-C

  1. Investigating the Combustion of Alcohols

    + 2 (C=O) + 1 (C?O) + 4 (O?H) 1 (O?H) + 11/2 (O=O) = [(3×413) + (1×358) + (1×464) + (11/2×498)] = [(2×-805) + (4×-464)] = 2808 kJ mol -1 =-3466 kJ mol -1 Enthalpy change of Combustion = Bond Making + Bond Breaking ?HC = (-3466) + (2808)

  2. An investigation into the heat of combustion of alcohol's

    bonds during combustion, it gives out more energy when the bonds are made as it has more bonds to make. My prediction was based on the theory of heat of combustion, I knew that in the reaction all the bonds of the reactants must be broken. This takes in energy.

  • Over 180,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work

Marked by a teacher

This essay has been marked by one of our great teachers. You can read the full teachers notes when you download the essay.

Peer reviewed

This essay has been reviewed by one of our specialist student essay reviewing squad. Read the full review on the essay page.

Peer reviewed

This essay has been reviewed by one of our specialist student essay reviewing squad. Read the full review under the essay preview on this page.