Yes it is easy to distinguish between both oxidation sates of copper metal. Also, my reactions seemed to take a very long time, particularly the reaction of the copper with zinc. Round-Trip Copper Reactions Lab The purpose of this lab was to evaluate our skills of decanting a supernatant liquid without losing the solid and successful completion of a series of reactions. After 5 more minutes it dries up but there was no specific color change and it remain yellow. Color changes, the generation of gases or precipitates and changes in temperature are all examples of the types of phenomena you should be looking for when studying chemical reactions. However, the extraction of metal can be done in one or two series of reactions but the metal could not be pure.
Turn off hot plate and carefully remove the beaker with the forceps. Collect the solids, and test the filtrate as described in the General Guidelines. When this happed during the decanting during the conversion to cupric acid, I had to wash the beakers I used for decanting with acid and poured that back into the original solution in an attempt to recover lost copper. By the end of the fifth reaction, the copper was back to its elemental state. Equipment: Balance 2 250 mL beakers Evaporating dish Stirring rod Hotplate 100 mL grad cylinder Weighing paper Materials: 0.
First reaction involves reaction between the copper and nitric acid, and copper changed from elemental state to an aqueous. Detailed instructions on how to write a lab report are provided on pages 10 — 15 of the. The most common natural ore is the sulphide, known as chalcocite, Cu2S. The experimental value for copper metal obtained was 0. Place in a 250 mL beaker and add about 4 mL of concentrated nitric acid slowly and carefully. After sulfuric acid was added to the beaker, copper was found as copper ions with a 2+ charge instead of the previous copper ii oxide form.
The copper metal is then separated using vacuum filtration method. In both cases I washed the stirring rod and magnet with distilled water over the beaker so the remains would drip into the solution, but some copper still may have remained on the. In the experiment we observed the every reaction which leads to compound and complex formation. Make sure you collect the supernatant or filtrate into a clean beaker or flask. The amount of elemental copper that you obtain from the last reaction will be a measure of the quality of your laboratory technique. In the ancient times, copper could be found lying in the ground in its unattached state without interaction to other substances. All in all, there was an abundance of sources of error in this lab.
In the next step, there was another chemical reaction when I added the sodium hydroxide. There are two ways to collect the supernatant or filtrate— decantation or filtration—depending on the physical appearance of the solid-liquid mixture. This was done through five chemical reactions involving copper. Once I put the sulfuric acid in it, the brown solids copper oxide slowly dissolved and turned the acid into blue. No one wants to read a lukewarm piece. Each student is to conduct his or her own cycle of this copper experiment as an individual.
It is important to realize that each product contains copper and that the total number of copper atoms involved in each step is the same. H2O crystals are heavy crystals. I heated the solution to evaporate the water and I got a brownish-blackish solid called copper oxide. When sulfuric acid was added to the copper oxide, the whole solution turned a blue color and no more black precipitate remained. You must legibly and correctly provide all identifying information requested above. For instant, for the first step, when I added the acid to the copper, the copper disappeared and the solution turned from the clear acid color to a blue-greenish hue.
After few minutes white precipitates settle down. In this experiment, several different types of reactions will be performed to transform copper into a variety of its compounds. Select the graduated cylinder with the volume closest to the volume you will be measuring. Error may have occurred at this step if the balance that was used to weight the copper was not calibrated correctly, or if the amount of copper weighed was not exactly the 2 g required. Filtrate, solution that goes through the filter, should be clear Empty the filtrate and rinse the filter flask with deionized water while the precipitate is still in the Buchner Funnel Replace the funnel over the cleaned filter flask. The final step I took was to add the element zinc, which turned the solution from blue to clear, with a brown solid in the bottom of the beaker, copper. Wet the filter paper using a minimal amount of water with the vacuum on, and slowly add the contents of your reaction beaker to the center of the funnel.
We also performed part of our experiment in a fume hood in order to protect ourselves from any potentially dangerous fumes. During the next step, error may have occurred if there was copper precipitate left on the side of the beaker instead of washed with water. Because of its distinct red color, Copper is very easily identified. Weigh a clean, dry evaporating dish and record the mass. Because some of the copper precipitate was so fine that it remained suspended in the solution some was inevitably lost during the decanting, if a filter had been used, this could have been avoided. When the time came to evaporate the solution, the liquids disappeared, leaving behind a wet, brownish solid in the middle of the beaker.
In this circumstance, it is good practice to continue adding reagent until no further precipitation is seen, collect the solid, and then test the solution that remains called the supernatant or filtrate for more precipitation by adding small amounts of more reagent to it. After 4 or 5 minutes its yellow color becomes brighter. The percent yield of copper calculated was 341. To complete this conversion, students first clean a piece of copper wire with steel wool and place the copper in a beaker. If it appears that all of the magnesium has reacted, but the solution is still colored from dissolved Cu 2+ , add more Mg.
Before the boiling process, the volume of mixture was 100 mL but after the boiling it decreases to 75 mL. As a result, the Law of Conservation of Mass was still held true, and the same amount of copper that was used initially was also found in the final product of the reaction. There may have been some copper left as an ion in the solution. This experiment is very dangerous because of the reactions between the strong acids and bases. The goal of this lab is to show students how the works. It is thought that man is responsible for the total destruction of the environment over this large area, but it is mostly contributed to the exclusive location.