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

Relationship between the increasing length of the carbon chain and the enthalpy of combustion of the alcohol that contains the carbon chain.

Extracts from this document...

Introduction

Relationship between the increasing length of the carbon chain and the enthalpy of combustion of the alcohol that contains the carbon chain. This experiment is carried out to determine whether there is a relationship between the increasing length of the carbon chain and the enthalpy of combustion of the alcohol that contains the carbon chain. If such a relationship arises can this information be used to predict the enthalpy change of combustion of any alcohol? This will hopefully be answered by the following experiment. The experiment will use known alcohols as heat source. The alcohol will be completely combusted this means that it will react with only the oxygen in the air to give carbon dioxide and water. Alcohols can be used as heat sources because they react exothermically. This means that when they react they give out more energy than they take in. In a reaction involving the complete combustion of an alcohol the bonds in that alcohol and the oxygen it is reacting with are broken. Energy is required for this to happen. These bonds then reform in a new order to make new compounds and chemicals in this case oxygen and water. ...read more.

Middle

This is the standard volume that all gasses occupy at room temperature and pressure (R.T.P) It was decided that the first four alcohols in the organic family would be used as the volume of oxygen required by the fifth to completely combust is more than the air can supply. This means that another source of oxygen would be needed for example a liquid oxygen tank. This is too expensive to be carried out in a school laboratory. This hypothesis from coursework.inf A theoretical value for the enthalpy change of combustion of each of the four alcohols can be worked out. This involves using the number and type of bonds and their corresponding bond energies. First the broken bonds are taken and worked out then the bonds that are made. As the bonds that are made give out energy this value is taken away from the value of the breaking bonds. This results in a negative number if the reaction is exothermic or a possitive number if it is endothermic. The energy released, as the carbon chain gets longer should increse. This is because there are more bonds to break and therefore more are made, this releases more energy. ...read more.

Conclusion

Alcohol Theoretical Values Values from Data book Methanol -679.55 -726.00 Ethanol -1297.10 -1367.00 Propanol -1914.65 -2021.00 Butanol -2535.20 -2675.60 The difference in the values shown, shows that the bond energy values used were only averages. An initial experiment was set up to investigate ways in which the experiment could be carried out in a more accurate and fair way. From this preliminary experiment it was determined that water would be placed in a copper calorimeter and placed above the spirit burner, ceramic heat mats would be used as draught excluders. It was also decided that the thermometer would be clamped with the bottom in the middle of the water and a stiring rod would be used to stir the water. This was so that the thermometer was not in contact with the calorimeter because if it were it would give the temperature of the calorimeter not the water. A copper calorimeter was chosen over a glass one because it conducted the heat through and into the water quicker and better. This was found when the two systems were tested. The possitioning of the copper calorimeter was chosen to be above the spirit burner instead of aside it, because heat rises so there would be a greater degree of error if it were placed to the side. ...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)

    carbon atoms and the heat of combustion is linear, therefore producing a line of best fit, going through the origin for all the graphs. This means that the heat of combustion (kJ/mol) is proportional to the size of the alcohol molecule (number of carbon atoms increases as the alcohol molecule becomes longer).

  2. Investigating the Combustion of Alcohols

    From these results, I obtained an average which was used in the calculations. However other factors such as any condensation of the alcohol back into the spirit burner and incomplete combustion were not taken into account and therefore not measured.

  1. How Does The Increase In The Length Of The Carbon Chain Affect The Energy ...

    So there is a +- 0.5�C possibility of anomalous results. The experiments will be repeated three times each to lessen the chance of an anomalous result. The mean amount will then be calculated and used to plot a graph.

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

    * The room temperature should be kept fairly constant. * The length of the wicks must be kept at similar lengths to stop the alcohols burning at different rates to each other and therefore having different amounts of heat loss.

  1. Comparing the Enthalpy Changes of Combustion of Different Alcohols

    'C' is the specific heat capacity of water, which is the value (4.17g-1K-1). In my experiment the value 4.2 J is used and is the amount of heat required to raise the temperature of 1 cm3 of water by 1?C.

  2. Measuring the Enthalpy Change of Combustion of Different Fuels

    --> 3 CO2 + 4 H2O OR 2 C3H7OH + 9 O2 --> 6 CO2 + 8 H2O Butan-1-ol: C4H9OH + 6 O2 --> 4 CO2 + 5 H2O Calculating Enthalpy Changes Energy Transferred in Joules (J) = cm?T c = the specific heating capacity of water (4.2 Jg-1K-1)

  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!

    But as soon as the zinc chloride melts, the bulb lights. Zinc starts to form around the cathode (the negative electrode). Chlorine gas is produced at the anode (the positive electrode). The bulb goes out when the heat is removed and the metal solidifies.

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