ChemistryEssay Preview: ChemistryReport this essayData/ ObservationsData:Measurements:Paper towel = 0.5100 gCu + Paper towel = 1.1000 gHNO3 = 5.01 mLH2O = 100 mLNaOH = 30.001 mLWax Plate = 2.291 gZn + Wax Plate = 4.693 gZn = 2.402 gMethanol = 5.19 mLAcetone = 5.30 mLEnd Product Cu + Wax Plate = 2.970 gEnd Product Cu = 0.679 gObservations:The copper at the beginning was a light reddish and powdery solid.When the HNO3 was added, the liquid turned green and produced an orange gas (NO2 (g)). There was a grainy substance on the bottom. There was no change in temperature.
When the NO2 was gone, the solution still smoked.When we added the water, the solution went from a green to a very crystal, pretty blue. The substance stopped smoking and the grainy substance at the bottom went away, it dissolved. There was no change in temperature.
After the NaOH was added, the solution turned a more vibrant and bright blue and had almost a jelly look to it. The jelly looked sort of like the lava in lava lamps because it was in small liquid/solid balls smooshed together.
When the blue, jelly substance stayed out for a while, it turned a little whitish at the top. Still no change in temperature.When the substance began to boil, it turned very black and grainy. The liquid was separate than the solid. It looked like dirt on the bottom of a lake or some body of water.
After we added the H2SO4, the liquid turned light blue again and the solids now float to the top. There did not seem to be as much solid as there was before.
When we added the Zn, the liquid turned brown and it sort of looked like hot chocolate. The “dirt” looking solid and the extra zinc stayed on the bottom of the beaker. The excess zinc kept bubbling, until it finally went away all together. This reaction actually changed in temperature. The beaker was very warm after it all denoting that the reaction was exothermic.
The last product of copper was a dark reddish brown and it still looks powdery and like dirt. It is much darker than the copper we used in the beginning of the experiment.
Calculations/ Results(We kept having to add more Zn to our solution because it had a bluish tint. This is the sum of the amount of Zn we had to put in it.)4.291 g Zn and Wax Plate + 0.134 g Zn + 0.134 g Zn + 0.134 g Zn =4.693 g Zn and Wax Plate(Zn + Wax Plate (g)) -Wax Plate (g) = Zn (g)4.693 g – 2.291 = 2.402 g Zn(End Cu + Wax Plate (g)) – Wax Plate (g) = End Cu (g)2.970 g – 2.291 g = 0.679 g CuPercent Yield = Experimental Value x 100%Theoretical Value0.679 g Cu x 100% = 135.8 % yield0.500 g CuConclusions:In this experiment, the goal was to recover all of the copper, in the end of the experiment, that we initially began with and to also calculate the percent yield. First of all, we measured out 0.500 g of copper(Cu) and put it in a beaker. Then, in the hood, we added about 5.00 mL of HNO3. The solution, the liquid turned green and there was grainy solid on the bottom of the beaker (Cu(NO3)2(aq) and H2O(l)), and it also produced an orange gas (NO2 (g)) along with a white wispy smoke after the NO2(g) was gone. When that reaction was complete, we then added 100 mL of H2O. The liquid went from green to a light blue and the solid at the bottom disappeared. There was no change in temperature in either of those reactions.
Next, we added 30.001 mL of 3.0 M NaOH, which caused the solution to look like a lava lamp almost. Everything turned a vibrant, bright blue where there was the liquid (NaNO3(aq)), and also a “lava” looking solid (Cu(OH)2(s)) which was in little ball shapes and smooshed together. We then added about 2 or 3 boiling chips into the solution and then we heated it up while stirring. When we finally reached the boiling point, the solution had turned black and it had little “specs of dirt” floating around. After the solution sat out for a while, the solids (CuO(s)) and the liquid (H2O(l)) separated with the water on top of the copper (II) oxide. Then we decanted the solution so that only the copper (II) oxide
and the liquid contained the same mixture of the two.
The top of the copper layer was melted as thin as possible (3.3 mm) and the bottom 3 mm of the copper was poured into an 18″ diameter 2×4″ piece that had the surface 4″ by 12 inches on the bottom. To keep the mixture clean, we put the heat in and continued with the top layer layer layer as above in the last section. In the following paragraph we have added about 10 mL to create as much NaOH as we could use at the bottom if needed. As a tip, we added 20 mL to the top of the copper layer layer and 2 mL of 1 H 2 O to the bottom if needed. Since we wanted the two components to be separated, we went back to the top and re-charted the mixture as we went.
We then added 50 mL to the copper layer where we could have a 3.5 to 5 gallon jug, which we added in a 5 gallon jug, as we were thinking about this part and the other. As you can see in the photo above, the copper layer was not melted down and this was the part where we had to add a small amount of copper when we added the rest of the molten aluminum (O 2 ) in our other batch. One of our workers used a 12/16″ hose to do this as one of the most helpful things about this project. The copper was washed thoroughly with a cool solvent and dried.
Once we had the water drained into the cooled pool, the process started.
1) Using a water bath for a time, we added 2 to 5 gallons of boiling hot water to a 3 gallon bucket (4 in depth). I used 2 to 4 gallons but you can easily pick up more to use in more complex applications. 2) When our pool was fully dissolved, we added about 1 1/2 -2.3 mL of water to the heated hot mixture. Then, we had to add 2 mL of water to a 17 2/4 to 5 gallon bucket (10 in depth). 4) When our boiling water had completely dissolved, we added 1 to 2 lbs of boiling water. In addition, we had to add a couple of drops of the cooling solution.
The solution came to 3 2/3 -3.43 L of boiling water and was then slowly stirred up. The ice and the mixture gradually cooled to a nice, gentle simmer. By the time we were talking to our helper about this, our solution was ready to pour. Just a few steps and we