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

The Heat of Combustion of alcohol.

Extracts from this document...


The Heat of Combustion of alcohol Hypothesis When alcohol is burned, the energy that is released can be transferred to the water in a calorimeter. The temperature rise can be used to calculate the amount of energy transferred. The structures of different alcohols are different from each other. They are a family of organic compounds. Alcohols are very flammable substances and burn well in the presence of oxygen, forming carbon dioxide and water vapour, and giving out plenty of energy. Example Ethanol C2H5OH (l) + 3O2 (g) 2CO2 (g) + 3H2O (g) + heat The different compounds follow a general pattern for the structure of CnH2n+2. The larger structure means the longer the chain and thus a higher the boiling point. This means that more heat is needed in order to break their bonds for those further down the chain of reactions. Aim Investigate which alcohol gives off the most energy when burnt in a spirit lamp. Prediction I predict that the alcohol that will give the most energy when burnt will be pentanol. Out of the five alchols which we will be testing (i.e. ...read more.


Propanol C3H7OH + 5O2 3CO2 + 4H2O 2 C-C 346 x 2 = 692 7 C-H 412 x 7 = 2884 1 C-O 358 x 1 = 358 1 O-H 464 x 1 = 464 5 O=O 498 x 5 = 2490 = +6888 Energy Given Out 6 C=O 743 x 6 = 4458 8 O-H 464 x 8 = 3712 = -8170 6888 + -8170 = -1282 kj/mol Energy needed to break bonds Butanol C4H9OH + 6O2 4CO2 + 5H2O 3 C-C 346 x 3 = 1038 9 C-H 412 x 9 = 3708 1 C-O 358 x 1 = 358 1 O-H 464 x 1 = 464 6 O=O 498 x 6 = 2988 = +8556 Energy Given Out 8 C=O 743 x 8 = 5944 10 O-H 464 x 10 = 4640 = -10584 8556 + -10584 = -2028 kj/mol Energy needed to break bonds Pentanol C5H11OH + O2 3CO2 + 4H2O 4 C-C 346 x 4 = 1384 11 C-H 412 x 11 = 4532 1 C-O 358 x 1 = 358 1 O-H 464 x 1 = 464 5 O=O 498 x 5 = 2490 = +6888 Energy Given Out 6 C=O 743 x 6 = 4458 8 O-H 464 x ...read more.


They are similar to the theoretical results. Supporting Prediction The results were true my prediction. They followed the same pattern as I had mentioned and the reasons for this seems from the results were also true for the same reasons. Conclusion The structure of the alcohol seems to be important in the time it takes for water to heat up. Not only does it mean the alcohol itself have more structure to burn but as a result what is given off when burnt also has more molecules and structure. Evaluation The test was satisfactory. The results had come out as planned and the theory was correct. The factors which would effect the test were taken into account as much as possible. One variable which was not dealt with was the fact that the heat was lost into the atmosphere. This could have been dealt with using draught screens but this could not be done due to insufficient supplies. Also accuracy was lost in that we were not able to repeat the test again due to time and practicality. I felt that everything else was accurate especially measuring the weight as we had an electronic scale to measure it for us. Overall the test was carried out sufficiently and the results were clear and of a high standard. ...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)

    This graph was certainly accurate as most of the points were either on the line of bets fit or drifting ever so slightly from it. On the other hand, my line of best fit was overall, lower than the processed data graph.

  2. The Combustion of Alcohols and the factors affecting these reactions

    The main source of error is the heat loss from the calorimeters and all the equipment used. There was also incomplete combustion as the flame was orange and soot was formed. The alcohols did not burn efficiently as of incomplete combustion and my results may have been affected.

  1. Esters. Esters are formed from an alcohol and carboxylic acid; this is an ...

    (e.g. rats) Yes / No/ Not Sure If yes what animals: Any other Information/ Comments about animals testing cosmetics: Data/Results These are the results for my questionnaire. Question 1- Do you buy cosmetics? Yes / No 24 people said yes and 6 people said no I would have thought that everyone would

  2. Investigate the enthalpy change of different alcohol

    Evaluation I think although this technique is not perfect, it gives me a rough approximation of the enthalpy change of different alcohol fuel. The way heat lost is roughly systematic, in other word, it loses the way in every trials, similar amount is lost to warm the room, similar amount is lost to the apparatus, etc.

  1. The aim of this investigation is to compare the enthalpy of the following different ...

    The general formula of the alkenes is CnH2n. They are unsaturated compounds. Alkenes are made from alkanes in crude oil. They are used in the manufacture of plastics and other polymers. In alkanes, all the bonds between carbon atoms are single bonds (C---C). Alkenes are different from them because they contain a double bond between two of their carbon atoms (C == C).

  2. Molar Heat of Combustion of Alcohols

    We heated the water in a copper calorimeter, a test tube and a beaker. Once we found out which vessel was the best we then tested this with a lid and draft excluder. We wanted to keep the preliminary tests fair so we used 25 ml of water each time

  1. In this report the effects of fire and explosion are examined based on quantitative ...

    The gas test flame is lowered into the containment vessel by the operation of a slide valve. The apparatus may be cooled by connecting a low-pressure air supply to the cooling air nozzle, at the back of the apparatus. 2.4 Description of Experimental Apparatus - The Critical Oxygen Index Equipment Diagram 3.

  2. GCSE Chemistry Revision Notes - everything!

    Bromine vapour diffusing from one gas jar to another. 3. Ammonia and hydrogen chloride gas diffusing towards each other in horizontal tube to give a white smoke ring where they meet and react with each other. Separating mixtures 1.

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