An investigation to see how the energy is released by burning alcohols depends on the number of carbon atoms they contain.

Authors Avatar

Ross Bowden 11RCB Chemistry Coursework

An investigation to see how the energy is released by burning alcohols depends on the number of carbon atoms they contain.

Planning

My objective for this experiment is to find out how the amount of energy released depends on the number of carbon atom present in the various alcohols. I will use 5 different alcohols, all with different numbers of carbon atoms. The alcohols I will use are: Methanol, Ethanol, Propanol, Butanol and Pentanol.

To work out how energy is released in each case, I will heat up a can fill with 150ml of distilled water by 15 degrees centigrade.

Variables I will keep the same throughout the investigation

I will need to keep these variables the same to ensure that this is a fair test.

  • The volume of water in the can. This is to be kept the same because the more water present, the more water particles there are that need to be heated up, which in turn will need a greater amount of energy. By keeping the amount of water present constant, I will see how much alcohol is needed to heat up that certain amount of water, which will tell me how much energy is needed. I will also throw out the water after each experiment and use fresh distilled water so that no excess heat is passed on to the next experiment.

  • The same can for each experiment. I will need to use the same can for each experiment because different metals conduct heat in different ways. A better or worse conduction of heat in the can may lead to less or more alcohol being burnt to increase the temperature of the water by the same amount. I will rinse the can out after each experiment to cool it down and so that it does not affect the temperature of the new water replacing the heated water.

  • The distance between the can and the flame. If the distance between the can and the flame is reduced, the can will conduct the heat better and more efficiently, thereby increasing the temperature of the water in the can faster and using less alcohol. If the distance between the can and the flame is increase, heat will be lost to the environment. Every time I do the experiment, I will place the flask of alcohol on the same two wooden blocks, to keep the distance between the flame and can constant.
Join now!

  • The wick of the alcohol burner. This needs to be kept constant because the flame will be bigger and hotter is there is a longer wick, or smaller and less hot if the wick is short. Obviously this would affect the rate of temperature increase of the water because a bigger hotter flame is more likely to heat up the water faster than a smaller less hot flame. I will keep this constant by measuring the length of the wick each time I do an experiment.

The Variable I will change

  • The alcohols. I will ...

This is a preview of the whole essay