Thermal Decomposition of Copper Carbonate

How much copper carbonate should be used to produce a sufficient amount of gas for collection? *(Calculation methods are shown bellow the table.)

EQUATION 1:

The number of moles of CuCO3 = 

                                      =

                                      = 0.0016194

The mole ratio between carbon dioxide and copper (I) oxide is 1:1 therefore there will be 0.0016194 moles of carbon dioxide present in the reaction.

The mole ratio between oxygen and copper carbonate is  : 2 and this is a quarter of the number of moles of copper carbonate. Therefore 0.0004048 moles of oxygen will be present in the reaction.

The volume of a given number of moles of gas (CO2 + O2) = Total no. moles x 24000cm3

                                                         = (0.0016194 + 0.0004048) x 24000

                                                         = 48.58 cm3

EQUATION 2:        

The number of moles of CuCO3 = 0.0016194

In this equation, the mole ration between copper (II) oxide and carbon dioxide is 1:1.

The volume of a given number of moles of gas (CO2) = no. moles x 24000cm3

                                                         = 0.0016194 x 24000

                                                         = 38.87 cm3

These calculations give a rough indication of the most suitable amount of copper carbonate to use for this experiment as well as the size of the measuring vessel that can be used to collect the gas that will be released during the decomposition of copper carbonate. And so, I will be using 0.2 grams of copper carbonate and a 50ml measuring cylinder.

If equation 1 is correct I expect the collected volume of gas to be about 48.58cm3. Assuming the presence of errors, the whole cylinder could result in being completely empty.

If equation 2 is correct I expect the collected volume of gas to be about 38.87 cm3. Assuming the presence of errors this value may vary ± 10cm3. This would still be less than that of the first equation. This would be enough information to identify which equation is correct.

Apparatus:

• Copper Carbonate - CuCO3 (s) –  0.20g
• 1 Test tube ( fitted with rubber stopper with glass tubing)
• Delivery tube
• Clamp and stand
• Big bucket
• Water
• Bunsen burner
• Matches
• Balance
• Spatula
• 50ml - Measuring cylinder
• Extra – Safety goggles

           - Gloves

• Access to a fume cupboard

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RISK ASSESSMENT:

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Method:

1. Set up the apparatus as above in a fume cupboard.
2. Fill up the measuring cylinder with water and submerge the open end under the water in the large bucket.
3. Weigh 0.20grams of copper carbonate in a test tube and close it with a stopper.
4. Attach the glass tubing on the stopper (of the test tube containing the copper carbonate) with its delivery tube under the measuring cylinder.
5. Heat the test tube with a Bunsen burner until the copper carbonate has fully decomposed.(The powder should change from blue-green to reddish brown).

6. We will see bubbles collecting in the measuring cylinder, the
   rate of CO2 release will begin to slow down when decomposition is near
   completion. When the bubbling stops, remove the heat and the delivery
   tube at the same time.

7. The measuring Cylinder will be held perpendicular in the water and the bottom of the meniscus will be read meniscus to determine the amount of water displaced
   by the gas.

8. This experiment will be repeated at least three more times to ensure accuracy of results.

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BIBLIOGRAPY:

Textbook:

1. 2004. GCE Moles, Formulae and Equations. “ The mole” pages 24 – 32, London: Edexcel

Websites:

1. Baltimore Polytechnic Institute, 2006. Decomposition of carbonates by heat [Online] Available at: <http://www.bpi.edu/ourpages/auto/2006/10/11/1160563714086/03-Decomposition%20of%20a%20carbonate.doc> [Accessed 08 December 2010]
   
2. Health and Safety Executive, General hazards of carbon dioxide [Online] Available at: <http://www.hse.gov.uk/carboncapture/carbondioxide.htm> [Accessed 07 December 2010]
   
3. Material safety Data sheet, 2005. Cupric Oxide [Online] Available at: <http://www.jtbaker.com/msds/englishhtml/C5885.htm> [Accessed 03 December 2010]
   
4. Material safety Data sheet, 2007. Cuprous Oxide [Online] Available at: <http://www.jtbaker.com/msds/englishhtml/c5971.htm> [Accessed 03 December 2010]
   
5. Practical Chemistry, 2008. Thermal Decomposition of Metal Carbonates [Online] Available at: <http://www.practicalchemistry.org/experiments/thermal-decomposition-of-metal-carbonates,281,EX.html> [Accessed 03 December 2010]
   
6. Riddle J.P, 1999. Copper Carbonate [ Online]  Available at: <http://www.ctmsupplies.hemscott.net/Copper%20Carbonate.htm> [Accessed 01December 2010]
   
7. Tutor Next, 2008. Decomposition Reactions [Online] Available at: <http://www.tutornext.com/decomposition-reactions/4043> [Accessed 07 December 2010]