Investigation to Find the Relative Energy Release of Five Alcohols: Ethanol, Methanol, Propanol, Butanol and Propanol

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Investigation to Find the Relative Energy Release of Five Alcohols: Ethanol, Methanol, Propanol, Butanol and Propanol

Aim:

In this experiment I will investigate to see which alcohol releases the most energy during combustion; Methanol, Ethanol, Propanol,
Butanol or Pentanol.

Hypothesis:

I think that the alcohols with the longest carbon chains will release the most energy. This is because when a bond is broken energy is released. This means that the alcohols with longer chains and therefore more bonds will release more energy. This will mean they will heat the water quickest. This should mean that Pentanol will heat the water by the largest mount in 5 minutes. However, because of the longer hydrocarbon chains and therefore more bonds,
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This proves my theory that the hydrocarbon with the longest carbon chain will release the most energy because it has a larger number of bonds than the other four alcohols in this investigation.

Preliminary Work:

Before I completed my experiment I completed some preliminary investigations. I completed an experiment to decide several potential variables within the final experiment. These include:

Ø The apparatus I will use in the final experiment (clamps, clam stands)

Ø The height the tin containing the water is away from the flame

Ø The amount of water

Ø The type of tin (percentage steel etc)

Ø Where the water comes from

I will burn three of the five alcohols: Ethanol, Propanol and Butanol.
Although I have tried the experiment with 50cm3 and 150cm3 of water I felt that 100cm3 was the better amount. I also tried different periods of time but I chose five minutes because it was the one which did not take too long, but allowed the water to be heated sufficiently for the experiment. I also tried different heights that the tin should be from the flame but I decided that 15cm would be the best choice as it allowed the heat to reach the tin, but wasn’t too low. I will use
100cm3 of water in a normal tin picked at random which will be used for all of the experiments.

For this preliminary work I only burnt Ethanol, Propanol and Butanol to get an

idea, rather
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