LAB REPORT FOR EXPERIMENT 3 COPPER CYCLE OLANREWAJU OYINDAMOLA
Abstract This experiment is based on copper, to synthesize some copper compound using Copper (II) nitrate solution to obtain copper metal at the end. Changes of copper complexes when various are added and filtering out the precipitate by using Buchner funnel for vacuum filtration. The experiment started with preparation of copper (II) hydroxide and addition of copper oxide then addition of droplets of chloride complex.
Then the addition of ammonium complex and the preparation of copper metal. And the vacuum filtration takes place.
Copper is a reddish-orange metal that is used widely in the electronics industry due to its properties of high ductility and conductivity. Results Reagents| Appearance| Volume (or Mass)| Concentration (or Molar Mass)| Cu(NO3)2 (aq)| Light blue solution| 10 ml| 0. 10 M| NaOH (aq)| Clear solution| 20 ml | 2 M| HCl (aq)| Clear solution| 20 drops| 6 M | NH3 (aq)| Clear solution| 7 drops| 6 M| H2SO4 (aq)| Clear solution| 15 ml | 1. M| Zn dust| Silvery substance| 0. 15 g| | ethanol| Clear solution| 5 ml | | Volume of Cu (NO3)2 (aq): 10 ml Concentration of Cu (NO3)2 (aq): 0. 10 M Convert ml to l: 10 / 1000 = 0. 010 liters Using the formulae: concentration = moles / volume 0. 10=moles/0. 010 Moles of Cu (NO3)2 (aq) = 0. 001 moles Mass of empty bottle = 6. 00grams Mass of empty bottle +copper metal =6. 05grams Mass of copper metal recovered after the experiment = 0. 050 grams Finding moles of copper: Moles = mass/ Mr = 0. 050 / 63. 55 =0. 00079 moles Volume of Cu (NO3)2 (aq): 10 ml
Concentration of Cu (NO3)2 (aq) : 0. 10 M Convert ml to l: 10 / 1000 = 0. 010 liters Using the formulae: concentration = moles / volume 0. 10=moles/0. 010 Moles of Cu (NO3)2 (aq) = 0. 001 moles Mass of empty bottle = 42. 53grams Mass of empty bottle +copper metal =42. 58grams Mass of copper metal recovered after the experiment = 0. 050 grams Finding moles of copper: Moles = mass/ Mr = 0. 05/ 63. 55 =0. 0008 moles Since we have got moles of copper metal and copper nitrate solution we can find the percentage yield of the copper metal obtained from the experiment. yield = actual value / theoretical value * 100% =moles of copper metal obtained/ moles of Cu (NO3)2 (aq) = 0. 0008/0. 001 * 100% =80% Thus the percentage yield of the copper obtained was 80 %. Addition of NaoH solution to Cu (NO3)2 gave a dark blue solution. After boiling the Solution gotten above, I sieved out the water and had CuO(s) left in the Beaker. The addition of HCl (drop wise) to CuO gave a yellowish green solution. When NH4OH solution was added it gave a yellowish green solution. I added 15ml of 1. m H2SO4 to yellowish green solution co I suspect the copper complex to be [Cu (H2O) 6]2+, since it gave a blue-green solution. When zinc dust was added to The solution a shiny reddish brown metal was formed. Discussion It is observed that copper was conserved throughout the experiment. And despite The conservation of copper in the reaction, the percentage recovery of copper is less than 100%. i had 80% of copper recovered from Cu (NO3)2. After pouring out the supernatant some CuO clung to the wall of the beaker.
Therefore, the HCl did not dissolve all of the CuO. This unreacted CuO causes a decrease in the mass of Cu recovered. Also, I forgot to scrunch the copper formed before drying. The clumps of copper might contain some water which increases its mass when weighed. It is necessary to synthesize the various compounds one after the other in order to recover copper metal because, it is not possible to get copper metal because it is not possible to get copper directly from Cu (NO3)2. all these phases are needed to be passed through.
When zinc is added a zinc hexaquo complex is formed from the bonding of Zn2+ with six molecules of water. The addition of H2SO4 causes the Cu2+ from Cu(OH)2 to combine with water molecules to form [Cu(H2O)6]2+. The Cu(OH)2 is gotten from reaction of CuCl2 with NH3. The percent yield depends on whether certain reactions were completed or not. my percent yield 80% is affected by incomplete reaction of CuO with HCl. During the decomposition of Cu (OH) 2, some Cu might have been lost in heat form.
Also when transferring the copper from the Buchner funnels into the weighing bottle, some copper metal were stuck to the funnel. This would also decrease the percent yield of copper gotten. Conclusion Given the concentration of Cu (NO3)2 and volume as 10. 0ml, the percent recovery of copper gotten from synthesis of copper compounds is 80%. References Cotton Albert; Wilkinson ,Geoffrey ;murillo,carlos;bochmann,Manfred. advanced inorganic chemistry,6th Ed; John Wiley and sons ltd:Canada,pp868-869