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

Experiment Hypothesis: The energy released by an alcohol increases as the number of carbon atoms increases.

Extracts from this document...

Introduction

´╗┐Applied Science coursework: Energy change in a reaction Aim: To carry out a series of combustion reaction in which energy is released and the various energies are compared for each reactant used. Introduction The presence of the ?OH means that hydrogen bonding occurs between the molecules of alcohol and also between the water. The hydrogen bonding has two consequences: The first it leads to boiling temperature (and melting temperature) being much higher than those of alkanes of comparable relative molecular mass. For example, butan-1-ol (Mr = 72) which boils at 309 K. The shorter chain alcohols are all liquids at room temperature. Decanol is the first solid. Secondly, alcohols with relatively short carbon chain tend to have a lower boiling and melting points than those that tend to have a larger carbon chain. The shorter carbon chain alcohols will tend to have weaker van der Waals forces, intermolecular force, between the alcohol molecules meaning that it will have a lower activation energy compared to an alcohol with a comparatively larger carbon chain. Intermolecular forces and bonds are of a number of types; dipole-dipole interactions and van der Waals forces and the hydrogen bond. ...read more.

Middle

-> CO2 (g) + H2O (g) This reaction is exothermic, as heat is given out. This is because the amount of reactant energy is more than the product energy the difference between this is energy is given off, therefore some energy has been given in the form of heat. The energy is given out in forming the bonds between the new water and carbon dioxide molecules. To measure the energy given off from the combustion, I must use this heat energy to heat something and this will water. This is assuming that all the heat produced by the combustion of the alcohol will be equal to the amount of heat absorbed by the water. So I will measure the amount of energy required to do so. There is no instrument which measures heat directly. So therefore I will have to arrange for the heat I wish to measure to be transferred into water and then I must measure the temperature rise. The heat is then given by the expression: Heat = Mass of water × Heat capacity of water × Temperature rise Heat = 1. ...read more.

Conclusion

Some errors were encountered in the experiment. This includes 1. The digital balance was not set accurately which resulted in errors in the data obtained from it. 2. The insulator used in covering the calorimeter was not changed which resulted in it absorbing heat during combustion but the was released back to the calorimeter, which resulted in temperature rise above expected value. 3. The spirit burner was not well insulated when burning so some of the heat escaped into the surrounding thus reducing the amount of heat absorbed by the water. 4. Parallax error involve in reading the thermometer. Despite the precautions that were taken during the experiment, some errors were also encountered in the experiment. Although the experiment in itself cannot be 100% accurate, but the result s that would be gotten can be improved by improving the methods used for carrying out the reaction. Such precautions includes: 1. Changing the insulator each time the experiment was carried out to reduce heat from warming up the calorimeter. 2. Cooling the calorimeter after every reaction. 3. Making sure the digital balance is set accurately to ensure accurate results. 4. Making sure the experiment was fully and well insulated with a good material that absorb heat readily. REFERENCE: A- LEVEL CHEMISTRY BY E.N RAMSDEN AND NEW SCHOOL CHEMISTRY BY ABABIO. ...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. Preparation of haloalkane. The purpose of this experiment is to prepare 2-chloro-2-methylpropane from ...

    materials to be distilled out or not enough heat for other reagents to react. Actually, the pear-shaped flask also helps with heating evenly, as the end of the flask is quite point-shaped which heats better than a flat-shaped base. Other errors in this experiment Besides loss of product and reagants, there were also some errors.

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

    When doing the experiment there are going to be very slight errors when measuring due to the instruments. In actual fact there is 3 instruments, which could have slight errors, this is the electronic balance, thermometer and measuring cylinder. I am going to show how to work out the percentage

  1. The Relationship Between The Number of Carbon Atoms In An Alcohol And Its Standard ...

    H 824 KJ 1 C --- C + 348 KJ Total energy Inputted: 1916 KJ I have worked out as shown above the extra figures that need to be added to the previous alcohol to find the new ?H of the alcohol that comes next in the series.

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

    + 302(g) 2CO2(g) + 3H2O(g) =5(C-H) + C-C + C-O + O-H + 3(O=O) =4(C=O) + 6(H-O) =5(410) + 350 + 360 + 460 + 3(496) =4(740) + 6(460) =2050 + 350 + 360 + 460 + 1488 =2960 + 2760 =+4708KJ/mol (bonds broken) =-5702KJ/mol (bonds formed)

  1. F336- aspirin individual Investigation

    Filter off the crystals using a Buchner funnel (vacuum Filtration), 5. Wash once with ice-cold water.-to remove any impurities however one must only was it once as you do not want to reduce yield of aspirin. 6. Dry your purified sample on filter paper and weigh it.

  2. Comparing The Enthalpy Change OfCombustion Of Different Alcohols

    These changes would reduce energy loss to the surroundings; to equipment and the air particles so increasing the amount of energy transferred and making the experiment more efficient. Incomplete combustion also forms part of the error as not all of the fuel was being burnt and so we would need

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

    * The capillary tube was placed in the melting point apparatus and the crystals were observed through a magnifying glass of the apparatus. * The range at which the aspirin melted was noted. The experiment was then repeated for pure aspirin. Results Compound Melting temperature (c) Re-crystalised aspirin 130-135 (c)

  2. Classifications of Alcohols Experiment

    This proves that 2-methyl-2-propanol is a tertiary alcohol. This is because tertiary alcohols don't have a hydrogen atom attached to that carbon. Since hydrogen atom is unable to be removed, hence no reaction will occur. Hence, tert-butanol is stable towards oxidation reaction. As for 2-butanol, a greenish solution is formed after heating.

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