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

To Investigate Whether There is a Link Between the Number of Carbon Atoms in Alcohol and its Standard Enthalpy of Combustion

Extracts from this document...


To Investigate Whether There is a Link Between the Number of Carbon Atoms in Alcohol and its Standard Enthalpy of Combustion Contents Introduction Alcohol is the common family name for the hydrocarbon group Alkanols. The generic formula of these organic compounds is: Cn.H(2n+1).OH The first example from the alkanol family is: Methanol - C.H3.OH From the generic formula we can see that different types of alcohols will have different number of carbon atoms. In this project I intend to investigate whether there is a link between the number of carbon atoms in alcohol and its standard enthalpy of combustion ?H. Planning Different members of the alcohol family have different numbers of carbon atoms and should therefore have different enthalpy ?H values. The complete combustion of an alcohol is when it reacts with oxygen in the air to form water and carbon dioxide. In this process energy is required to break the existing chemical bonds (endothermic reaction) and energy is given out by the creation of new chemical bonds (exothermic reaction). If the heat of combustion is a -?H the reaction is exothermic as the products of combustion are at a lower energy level than the reactants. ...read more.


* Then measure 200 cm3 of water using the measuring cylinder and pour it into the water beaker. * Then a thermometer is used to measure the initial temperature of the water, which should also be recorded. * A lit splint (using the Bunsen burner) is used to light the wick of the alcohol bottle. * The water beaker, containing the water, is to be instantly placed over the burning alcohol on the draught proof tin * Once the temperature of the water reaches approximately 40 degrees Celsius the wick is blown out. * Finally the alcohol bottle is to be removed and re-weighed, and the new mass recorded. Diagram: Safety * Wear safety glasses. * Tie back long hair, tuck in school ties, and button up cuffs. * Ensure there are no naked flames near alcohol being stored or measured. * Clean up any alcohol spills immediately. * Take care not to handle hot apparatus, allow cooling before dismantling and cleaning. * Wear an apron. * If spilt on skin or clothing remove affected clothing to prevent fire risk and wash affected area. ...read more.


This can be used to calculate the theoretical enthalpy of combustion for the alcohols of this investigation. Below is a list showing the theoretical enthalpy of combustion for these alcohols. Methanol = - 659 Ethanol = -1031 Butanol = - 2023 Pentanol = - 2301 Heptanol = - 3511 Octanol = - 4007 As you can see a longer molecule takes more energy to break its bonds, compared to a smaller molecule. However, as the carbon length increases the greater the number of carbon dioxide and water molecules produced as a result of the combustion of the alcohol. This is because the energy released due to the creation of the increasing number of C=O bonds are far greater than the bonds being broken. Hence the net result is exothermic process. Therefore I expect there to be a trend going upwards on my graph. Methanol will have the lowest reading, and as the number of carbons increase in the different alcohols their readings will increase. Therefore I expect the results to be close to my prediction, having considered the theory bond energy. Chemistry Coursework Anil Sood 11G ...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. Find the enthalpy change of combustion of a number of alcohol's' so that you ...

    I need to keep as many of the factors in my experiments as I can the same, only changing what I have to, the variables, so that I get as accurate results as possible showing the correct pattern. I don't know how or whether the positions of the OH group

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

    An endothermic reaction will be the opposite. With this piece of information, I can firstly work out the true values through the above 'formula' but to work out these for my own experiment is a much harder task. Below, the Enthalpy Change of Combustion is stated and shown for the first alcohol, methanol: Methanol + Oxygen Carbon

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

    =-5702KJ/mol (bonds formed) H =+4708-5702 =-994KJ/mol Propanol CH3CH2CH2OH H H H H-C-C-C-O-H H H H CH3CH2CH2OH(l)+4.5O2(g) 3CO2(g) +4H2O(g) =7(C-H) + 2(C-C) + C-O + O-H + 4.5(O=O) =6(C=O) + 8(H-O) =7(410) + 2(350) + 360 + 460 + 4.5(496) =6(740) + 8(460) =2870 + 700 + 360 + 460 +2232 =4440 + 3680 =+6622KJ/mol (bonds broken)

  2. F336- aspirin individual Investigation

    This is known as spotting. Spotting is achieved by repeated applications of the mixture from a capillary pipette (figure 1). When the filled pipette touches the plate, the liquid is delivered on to the plate by capillary action. The plate is immersed in a development chamber that contains a solvent or a mixture of solvents.

  1. Comparing The Enthalpy Change OfCombustion Of Different Alcohols

    Methanol -300/-618 49 Ethanol -620/-1276) 49 Propan-1-ol -940/-1894 50 Butan-1-ol -1260/-2512 50 Pentanol -1580/-3130 50 The table shows that all my experiments were about 50% accurate which means that the energy transfer from the flame to the water and copper container was very inefficient (about 50%).

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

    Using a small funnel, 5-10cm3 of the prepared solution of 0.1mol dm-3 sodium hydroxide was added to the burette. The funnel was then removed. The burette was then taken from the stand and tipped and rotated to wash the inside surface with the solution.

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

    It does depend on how much of the substance is present. Heat always flows high to low temperature, so heat will flow from a red hot nail into a bucket full of lukewarm water, even though the total heat content of the water is greater than that of the nail.

  2. Aspirin Research Project

    This enables for the carboxylic acid group of the aspirin molecule to convert to a water-soluble carboxylate which becomes ionic when the tablet is reacted with water (Aus-e-tute, 2013). In effect, aspirin becomes sodium acetylsalicylate which is water soluble as it forms ion ?dipole bonds with water molecules. (Aus-e-tute, 2013)

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