# determine the correct equation

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Introduction

Aim- To determines the correct equation of the thermal decomposition of copper carbonate. The two possible equations are shown below: Equation 1: 2CuCO� (s) --> Cu�O (s) + 2CO� (g) + 1/2O� (g) Equation 2: CuCO� (s) --> CuO (s) + CO� (g) Apparatus * Heat mat * Clamp stand * 100ml gas syringe * Conical flask * Bunsen burner * Tripod * Tube/hose with bung attachment * Top-pan balance * Gauze Chemicals Powdered copper carbonate Calculations I expected the volume of gas would be 80cm�. This is because the bigger the volume of gas, the smaller the percentage error for the gas syringe as it is 100ml which has small graduations and big scale. V/24000 = n 80/24000=3.33 x10-� m/Mr = n Mr x n =m Mr=molar mass n=mole m= mass R.M.M of copper carbonate = 63.5 + 12 + (16 x 3) = 123.5 grams 123.5 x 3.33 x10-� =0.4g So in this experiment, I decide to use 0.4g of copper carbonate. ...read more.

Middle

Using 0.1 grams of copper carbonate: Moles of copper carbonate used = mass / relative molecular mass Mass = 0.4 grams R.M.M of copper carbonate = 63.5 + 12 + (16 x 3) = 123.5 grams Moles = 0.4 / 123.5 = 3.24 x 10-3 If we now compare the moles of copper carbonate to the moles of gas (carbon dioxide) given off with find that the molar ratio of the equation is 1:1. As the equation is a 1:1 equation then the moles of gas are the same as the moles of carbon carbonate. I shall now again use the equation above to calculate the gas produced to actual room temperature and pressure. n=v/24000 n= mole v=volume of gas Moles = 3.24 x 10-3moles 3.24 x 10-3=v/24000 Then rearrange the formula to n x 24000=v 3.24 x 10-3x 24000=77.76 cm� My two expected volumes of gas are 77.76 cm3 and 97.2 cm3, These are big enough for me to be able to use the more accurate, syringe, method of collecting gas, this should make my experiment more accurate. ...read more.

Conclusion

7. Wait 20 minutes until the gas has returned to room temperature as when it is hot it will expand and take up more volume. So to acquire a correct volume of gas we must wait for it too return to room temperature, approx 20oC, so that the volume is correct for a temperature of 20oC. 8. After 20 minutes record volume of gas. Safety Remember as we are using a Bunsen burner to wear goggle and a safety apron at all time and leave Bunsen burner on a safety flame when not in use Result Compare the recorded gas produced to out theoretical values. Expected gas produced for equation 1= 97.2cm� If the gas given off was between 95.00 - 100.00cm� then equation 1 was the correct equation for the decomposition of copper carbonate. Expected gas produced for equation 2 = 77.76 cm� If the gas given off was between 75.00 - 80.00 cm� then equation 2 was the correct equation for the decomposing of copper carbonate. ...read more.

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