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

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

Extracts from this document...

Introduction

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. ...read more.

Middle

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 20�C 21�C 21�C 22�C Finishing temperature 40�C 41�C 41�C 42�C Temperature change 20�C 20�C 20�C 20�C 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, ...read more.

Conclusion

+/- 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 ...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. Marked by a teacher

    Experiment to investigate the heat of combustion of alcohols.

    4 star(s)

    as a pose to it being taken in (endothermic), is much larger as the Carbon atoms increase. Preliminary Work. Also to back up my prediction further, I have produced results from a similar experiment, I had previously carried out, only with 5 alcohols instead of 6.

  2. Titration experiment - write up

    20) Repeat steps 11 - 16. This time, once the burette reading is 3 cm3 above the rough titration reading. Add drop by drop, controlling the tap very carefully. Use one hand to swirl, and the other to operate the tap. Repeat the titration until three concordant titres are achieved all within 0.1 of each other.

  1. Investigating the Combustion of Alcohols

    Once weighed, place the spirit burner beneath the calorimeter ensuring there is a distance of 5 cm between the wick and the calorimeter container. 6. Surround the spirit burner with heat proof mats for the heat and energy to be shielded and to ensure draughts do not put out the flame.

  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. Enthalpy Change - Alcohols

    The method of the experiment: firstly, I will need to setup the calorimeter; by placing 600ml of water inside it; then let it equilibrate; while it is equilibrating I will attach the water pump, one end on the calorimeter and the other on a tap.

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

    I have also decided to use structural isomers of two of these, Propanol and Butanol. (Propan-1-ol and Propan-2-ol and Butan-1-ol and Butan-2-ol). This will allow me to compare the enthalpy of combustion of increasing chain length and the structural isomers of some of these alcohols.

  1. Investigate the enthalpy change of different alcohol

    Vaporization of some alcohol would give us a wrong weight result. 5. All equipments are washed with distill water and dried completely before the experiment. These prevent contamination with unwanted ions that have left over on the equipments before. 6.

  2. GCSE Chemistry Revision Notes - everything!

    They usually have a shiny appearance. They often form more than one positive ion. For example, iron forms iron (II) ions, Fe2+, and iron (III) ions, Fe3+. This property is called variable valency. Their compounds are often coloured. Transition meals and their compounds are often good catalysts.

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