Alcohol Heat Combustion Investigation

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Combustion of Alcohols                                                                                 Sam Norton

Introduction

The investigation that is being performed is designed to find out which from a range of alcohols is giving out the most energy when it is burnt. I am using Methanol, Ethanol, Propenol and Butan. I will investigate this by burning the alcohols (separately) under a beaker full of water. In order to collect data I will weigh the alcohol being burned before and after the experiment. The experiment is over when the water in the beaker has been heated for a set time.

Using the data collected and the bond energy values for the equation of the burning of each alcohol, I can calculate which contains most energy and precisely how much Ki/mol each gives out.

Method

The experiment was set up as below,

The experiment was done in 9 stages,

1. Set the equipment up as above.

2. Weigh and record the alcohol.

3. Place the alcohol 10cm underneath the beaker, which will be filled with 200ml of water.

4. Record temperature of water watching carefully until it reaches 40 C.

5. Extinguish the flame.

6. Weigh the alcohol again and recorded.

7. Replace water with cool water after the beaker has returned to room temperature

8. Repeat the stage for the same alcohol.

9. Repeat method for the other alcohols.

How was it made a fair test?

To make this a fair test I had to keep all the variables the same when using all alcohols

The variables I needed to keep the same were:

        Volume of water because if I didn’t then it will take more energy to heat the

larger volumes than it would the smaller volumes.  I decided to use 200ml of

water because I thought if I used any more it would take up a lot more

energy from the alcohol and would have taken a long time for the experiment to be repeated.

        Same equipment setup because if I didn’t the alcohol could be closer to the flame

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or further away which would either give the water more or less energy.

        Stir the water so that it is heated evenly otherwise energy would only reach

parts of the water and depending on where you placed your thermometer you could

get different results.

Prediction

I predict that the more bonds there are holding the carbon, oxygen and hydrogen atoms together, more energy will be required to break them apart. For example Ethanol has the formula C H OH. In this formula you have five C-H bonds, one C-C bond, one C-O bond and one O-H bond. To separate ...

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