Energy Produced by Burning Five Alcohols

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How much energy is produced when burning five alcohols

· Methanol
· Ethanol,
· Propanol,
· Butanol
· Pentanol.

The aim is to find out how much energy is produced when burning these alcohols. The reaction that is involved in burning alcohols is exothermic because heat is given out. Form this reason the reactant energy is higher than that of the product.

The energy is given out when forming the bonds between the new water and carbon dioxide molecules. The amount of energy produced by such exothermic reactions can be calculated by using the formula :

Mass of the substance x rise in temp x SHC( specific heat capacity).

The specific heat capacity is the number of joules required to heat one gram of water by 1ºC. I chose to use water because it is safe, easily found, and has a reliable specific heat capacity of 4.2.

The bond that are formed in an exothermic reaction can be of two types. The first could be ionic, where a metal is produced. Ionic bonding involves electrons transferring from one atom to the other consequently leaving an electrostatic force between them. The other form of bonding is covalent where atoms share electrons to complete their outer orbit. An example being Methane where four hydrogen atoms each share an electron with a carbon atom.

GRAPH

Alcohol

The method that I will use is as follows:

· Measure 100cm of water in to a glass beaker
· Place the beaker into the grasp of the clamp stand.
· Record the starting temperature of the water
· Weigh the spirit burner with the lid on.
· Put the chosen alcohol burner under the beaker allowing the flame to just touch the beaker.
· Leave to heat up until the temperature of the water is exactly 50ºC more than the original temperatur...

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...nother error is that of incomplete combustion. Complete combustion occurs if there are lots of oxygen atoms available when the fuel burns, then you get carbon dioxide (carbons atoms bond with two oxygen atoms). If there is a limited supply of oxygen then you get carbon monoxide
(each carbon atom can only bond with one oxygen atom). This is when incomplete combustion has occurred. This is so because the carbon monoxide could react some more to make carbon dioxide. If the oxygen supply is very limited then you get some atoms of carbon released before they can bond with any oxygen atoms. This is what we call soot.
Since heat is given out when bonds form, less energy is given out by incomplete combustion. So this is why it affects the outcome of the experiment. To overcome this problem, I would have to make sure a sufficient supply of oxygen was involved in the reaction.

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