• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11

Alcohols as fuels.

Extracts from this document...

Introduction

Alcohols as fuels Introduction: Alcohols, as most of us know burn quite well in air (they react with oxygen when heated in air). This means we could use alcohol as a fuel to produce energy, as the reaction with air is exothermic. What effect would using different alcohols as fuels have? We might expect to find that larger alcohol molecules could be burned to give out larger amounts of energy, as the structure contains more chains of molecules which can react with oxygen to release more energy. In this investigation, we shall test a range of alcohols to see how much energy each releases when combusted. Plan: We shall be investigating how different alcohols give out different amounts of energy when burnt in air. We shall be using methanol, ethanol, propanol, butanol and pentan-1-ol in this investigation. The best way to perform the experiment to find out how much energy is given out by each alcohol is to use alcohol burners. These are short glass cylinders which are sealed off at the top. They have a short piece of rope reaching from the bottom of inside the burner (where the alcohol would be) to a hole with a metal ring at the top of the burner. The metal ring can be taken off with the rope to refill the burner. We shall use these alcohol burners to heat up a metal beaker of 50ml of water by 40�C. We shall use a thermometer to measure this heat change. ...read more.

Middle

Butanol gives nearly one thousand kJ mol-1 more than propanol and has 4 carbon atoms. Butanol gives out the most energy during the combustion of one of its molecules. From these calculations using theoretical values for bond energies from my chemistry book, ("GCSE Chemistry" by B. Earl & L. D. R. Wilford), I am able to predict which alcohol will be the most productive in terms of energy. The following graphs show what I predict will be the outcome of these experiments: As we can see, I think the mass difference between before and after weights shall decrease as we use alcohols with more carbon atoms in one molecule. As I have said, this is because the bonds produce more energy when there are more of then, more energy than the bonds take to break. Results: Methanol Mass (g) before After (g) before Difference (g) 1. 109.56 108.16 1.4 2. 108.13 106.92 1.21 3. 106.83 105.5 1.33 Ethanol 1. 111.7 110.52 1.18 2. 113.29 112.29 1 3. 112.24 111.12 1.12 Propanol 1. 113.08 112.44 0.64 2. 112.42 111.69 0.73 3. 111.64 110.95 0.69 Butanol 1. 116.94 116.05 0.89 2. 116.03 115.24 0.79 3. 115.22 114.35 0.87 Pentan-1-ol 1. 116.05 115.3 0.75 2. 115.28 114.62 0.66 3. 114.6 113.92 0.68 Methanol Ethanol Propanol Butanol Pentan-1-ol Average difference (grams) 1.31 1.1 0.69 0.85 0.70 Using the formula below, I can roughly see how much energy was needed to raise the temperature of the water by burning different alcohols. ...read more.

Conclusion

Also, the average difference for propanol and pentan-1-ol was very similar - the difference between these two results was a mere hundredth of a gram, showing them to be almost exactly the same in terms of heating up 50g of water. I have worked out the efficiencies of our experiments, and on average they were about 30% efficient. This was unavoidable due to the limitations in our abilities and equipment. The experiment could have been made more efficient using a bomb calorimeter. Calorimetry is the science of measuring a quantity of thermal energy in the process of heat transfer. A calorimeter is an instrument used to measure the amount of thermal energy; one widely used type consists of an insulated container of water, a stirring device, and a thermometer. A heat source is placed in the calorimeter, the water is stirred until equilibrium is reached, and the rise of temperature is noted by reading the thermometer. Because the heat capacity of the calorimeter is known, (or can be measured by using a standard heat source) the amount of energy given out can be easily calculated. When the heat source is a chemical reaction, such as the burning of a fuel, the reacting substances are placed in a heavy steel vessel called a bomb. The bomb is placed within the calorimeter, and the reaction is started by ignition with an electric spark. This would greatly increase efficiency as all heat would be used to heat the water. To further extend this work on alcohols, we could try using more alcohols, to obtain more results. Nicholas Moore 11Mc Group Q Mr Tansley 1 ...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. How Does The Increase In The Length Of The Carbon Chain Affect The Energy ...

    834.51 3 188.94 187.83 1.11 16800 15.14 908.11 1 182.81 181.07 1,74 16800 9.66 714.48 Butanol 2 181.07 179.86 1.21 16800 13.88 13.13 1027.44 971.58 3 179.86 178.80 1.06 16800 15.85 1172.83 1 184.87 183.75 1.12 16800 15.00 1320.00 Pentanol 2 183.63 182.72 0.91 16800 18.46 16.39 1624.62 1442.10 3

  2. THE LINK BETWEEN CARBON ATOMS IN A FUEL AND THE ENERGY IT RELEASES.

    Heat evolved in ethanol 1st attempt = (4.8?76.33?4.2) + (4.8?77.21?0.385) 1538.8128+142.4808 1681.2936joules 2nd attempt = (5.2?75.15?4.2) + (5.2?77.21?0.385) 1641.276+154.57442 1795.85042joules 3rd attempt = (5.5?73.46?4.2) + (5.5?77.21?0.385) 1696.926+163.492175 1860.418175joules Heat evolved in propan-1-ol 1st attempt = (4.7?75.15?4.2) + (4.7?77.21?0.385) 1483.461+ 118.9034 1602.3644joules 2nd attempt = (4.7?75.85?4.2) + (4.7?77.21?0.385) 1497.279+139.711495 1636.987495joules 3rd attempt = (5.3?75.99?4.2)

  1. To determine which alcohol, out of ethanol and propanol, is the better fuel. By ...

    Measurements to be taken: Mass of Water Change in temperature = End temperature - initial temperature Initial mass of alcohol = mass of burner and alcohol - mass of empty burner Final mass of alcohol = mass of burner and alcohol at end of experiment - mass of empty burner.

  2. Burning Fuels - Fuels are substances that release energy when they react with oxygen. ...

    It is used in the blast furnace to extract iron from iron ore. Solid fuels like coal are easy to transport and store. However, they can be hard to ignite, and (in the case of coal), release pollutants on burning.

  1. Find out the heat of combustion in the five fuels; Methanol, Ethanol, Propanol, Butanol, ...

    x Temp change(c) x specific heat capacity(j) 30 20 1/4 4.2 = 2614.5 joules of heat transferred For I gram of Butanol 12.415 12.01- 00.405= weight of fuel burnt 6455.5= energy given for I gram 0.405 2614.5 Pentanol; Heat transfer=mass(g)

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

    group in the molecule which alters the position of the electromagnetic poles. If we study butan-1-ol and butan-2-ol we can see that this is not the case according to the results. But it has been scientifically proven that this is what should happen; these anomalous results can be put down to the technique used in the experiment, i.e.

  1. Investigate the enthalpy change of different alcohol

    of energy per mole, the trend would be the bigger the mass, the more energy it yields. The reason is the longer the chain, the more products will form. And because the C=O and O=H bonds in products CO2 and H2O are more stable than the C-H bonds in alcohol

  2. An experiment to investigate the factors that determine the amount of energy released when ...

    The amount of water in the beaker to 50ml b) The distance between the top of the crucible and the base of the beaker to 2.5cm. Background Knowledge Hydrocarbons In organic chemistry, hydrocarbons are a family of organic compounds composed entirely of carbon and hydrogen.

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