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

Investigating the enthalpy change of different alcohols

Extracts from this document...

Introduction

Investigating the enthalpy change of different alcohols Method In this investigation I am going to try to find out if there is a relationship between different lengths of alcohol chains and their combustion enthalpy change. I am going to do this by using spirit burners and a calorimeter. I will burn the fuel until it has heated up the water in the calorimeter until it is a certain temperature, then I can use the heat capacity of the water and the molecular formula of the alcohol to work out the enthalpy change. Here is my draft method: Equipment: * Aluminium can to act as calorimeter, about 10cm in diameter and able to hold about 200ml of water. * 0-50?c thermometer (or 0-110?c if 0-50?c not available). * 200ml measuring cylinder. * Spirit burners containing: Methanol Ethanol Propan-1-ol Butan-1-ol * Balance (accurate to 2 decimal places). * Clamp stand, clamp, heat mats. Set-up: Method: 1. Record temperature of water in calorimeter. 1. Weigh spirit burner and record. 1. Light spirit burner. 1. Keep burner lit until the temperature of the water is 20?c higher and record. ...read more.

Middle

This makes it more accurate as we are taking into account all the energy that is produced by the flame. * When taking the temperature of the water I will use the thermometer to stir the water as well as taking the temperature, as this will make sure that the heat is evenly distributed and therefore it will insure that the test is as fair as possible. * When it comes round to putting out the flame I will use the lid and not blow it out so that none of the fuel is lost to evaporation or anything. The lid will also be kept on until the weighing process. * I will use a mercury thermometer as this is more accurate then an alcohol one and therefore will reduce the percentage errors. * I will use the same equipment every time e.g. calorimeter, clamp, clamp stand, heat mat, thermometer. This is so that all the experiments are fair as different equipment is sometimes slightly off calibration so that at least if it is not greatly accurate it is relative so I can find a trend if there is one. ...read more.

Conclusion

In the combustion of alcohols, energy is given out at a higher ratio than it is taken in again by making the bonds, therefore the more bonds the higher the overall amount of energy given out. Here is a balanced equation for the combustion of an alcohol in a surplus of oxygen: CnOH + (n/2) O2 (n/3) CO2 + (2n/3) H2O For Methanol this is: C3OH + 1.5 O2 CO2 + 2 H2O From this I can draw these diagrams to produce a simple way of working out the bonds that are broken and made: Using the figures from data books as a reference and the number of bonds broken and made from my drawings I can show my prediction in these tables: Bond Enthalpy change (kJ mol-1) C-C 347 C-H 413 H-O 464 O=O 498 C-O 358 C=O 805 Fuel Bonds Initial energy absorbed (kJ mol-1) C-C C-H H-O C-O O=O Methanol 0 3 1 1 1.5 2808 Ethanol 1 5 1 1 3.5 4977 Propan-1-ol 2 7 1 1 5.5 7146 Butan-1-ol 3 9 1 1 7.5 9315 Fuel Bonds Final energy released (kJ mol-1) Overall enthalpy change (kJ mol-1) H-O Bottom of Form ...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

    What an ester is, how it is made, examples of esters, animal testing issues ...

    4 star(s)

    Experiment 1: Reactions of dilute ethanoic acid 1. When ethanoic acid is put on yellow litmus paper, the litmus paper turns red. Meaning ethanoic acid is very acidic as the Ph is 1. 2. When a tube is filled with a 1/3 of dilute ethanoic acid and a piece of

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

    Check that the digital scales show a reading of 0.00g. * Record the final weight in the table. * Empty the contents of the calorimeter into the sink and rinse with water to cool the can and wash off any soot that has accumulated on the bottom and sides of the can.

  1. Investigate the enthalpy change of different alcohol

    Carbon is actually attached to oxygen in OH group, while hydrogen is attached to oxygen. OH has a valency of 1 and carbon has a valency of 4, therefore each contributes an electron and forms a covalent bond in between. Butan-1-ol and propan-1-ol both have their functional group (OH-hydroxyl group)

  2. Comparing the enthalpy changes of different alcohols

    Use the thermometer to measure when the temperature has risen by 17�C. 7) Snuff the flame on the spirit burner and continue stirring the water and note the highest temperature reached. 8) Reweigh the spirit burner, to see how much fuel was used (use the same balance and ensure the stopper was replaced before reweighing)

  1. Molar Heat of Combustion of Alcohols

    Therefore there is a net energy gain every time. Preliminary Experiment: We heated 25ml of water for two minutes in a copper calorimeter, a test-tube and a beaker, we took the temperature and the weight of the burner before and after testing because we can work out which container is the most effective from that.

  2. What is crude oil?

    If allowed to escape into the atmosphere, it can cause acid smut fallout and boiler cold-temperature corrosion. What is a catalytic converter and how does it work? A catalytic converter is a device that uses a catalyst to convert three harmful compounds in car exhaust into harmless compounds.

  1. To investigate the relationship between the structure and heat produced by combustion for a ...

    if a reaction causes one thing to occur, the reverse reaction will cause the reverse result. Basically, breaking bonds is endothermic and making bonds is exothermic. Its already been established that combustion is an exothermic reaction. This means that the energy absorbed to break the bonds of the alcohol is

  2. GCSE Chemistry Revision Notes - everything!

    the flame is yellow-orange, the metal is Sodium If the flame is orange-red, the metal is Calcium If the flame is pale green, the metal is Barium Hydroxides Because most hydroxides are insoluble (except sodium, potassium and ammonium hydroxides), when you add sodium hydroxide solution to a solution containing metal ions, you will get a precipitate of the metal hydroxide.

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