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Introduction

Which Equation is Correct? Planning The aim of this experiment is to discover which of the following equations is correct for the decomposition of CuCO3. The two equations that I am going to use are: 2CuCO3 (s) ? Cu2O (s) + 2CO2 (g) + 1/2O2 (g) CuCO3 (s) ? CuO (s) + CO2 (g) In order to do this I must research the process in which the reaction takes place and calculate the amount of gas that is produced for both equations. This will allow me to determine the correct equation by using the results of the experiment and the results of my calculations. I gave designed three experiments using similar apparatus in order to discover which of the two equations are correct. I will compare the three experiments stating the pro's and con's of each experiment. Research Thermal Decomposition "A chemical reaction in which a single compound is broken into two or more simpler compounds or elements. This is an endothermic reaction which requires an external heat source. This reaction is irreversible." (Resource: http://www.Dictionary.com/thermal_decomposition.html) Copper Carbonate This is typically solid at room temperature and pressure (r.t.p). ...read more.

Middle

Place the test tube rack on the gauze and light the Bunsen burner. (Don't forget to wear safety spectacles). Wait for the gas produced to displace the water. Calculate the amount of gas produced using the reference that was taken. Method 2 Almost exactly the same as method 1 but instead of using a measuring cylinder use an upturned burette making sure that the valve is closed yet still take a reference. For this you will have to use a burette clamp as it is very fragile and may break. Method 3 With this method there is no need for the water bath or the clamp stand. Instead you will use a syringe to measure the gas produced directly. To do this attach the rubber tubing to the bung and a syringe. Make sure that the plunger is fully compressed and that you allow the as to cool before taking a reading as the temperature will affect the results. Chosen Method I have chosen method 3 as my preferred method. This is because there are fewer inaccuracies using a syringe. This is because all the gas is collected in the syringe and any Carbon Dioxide may produced may not dissolve in the water bath. ...read more.

Conclusion

This tells me which equation is correct. Errors in Procedure There are several procedure errors that can occur. I will state and suggest ways to improve two of them. 1. There could be some compression of the gas in the syringe. This could be solved by allowing the gas to be cooled before taking the reading. This is because the gas expands when it is given energy. 2. The other error is that Carbon Dioxide can dissolve in water, and is also heavier than oxygen. The as produced could be lost in the water or the pressure created by the gases weight may affect the readings in the measuring cylinder and burette. Errors in Measurement There may also be errors in measurement because of the accuracy of the devices used. 1. A measuring cylinder does not have very many markings on it and they are spaced further apart than required. This makes it more difficult to estimate in between markings and may affect your results. 2. The scales used to weigh the mass of the Copper carbonate may not be accurate enough as a mass of 2d.p. is required and most available scales read no more than 2d.p. as 3d.p. is more preferable. Method Diagrams ?? ?? ?? ?? Jonathon Higham 12B ...read more.

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