action between the Elements Copper and Sulfur PERFORM TH IS EXPERIMENT IN THE HO
ID: 550560 • Letter: A
Question
action between the Elements Copper and Sulfur PERFORM TH IS EXPERIMENT IN THE HOOD WITH A PARTNER. Obtain about a 5 cm (2 in.) length of copper wire and note its properties. surface is shiny, that it can be easily bent, and that it has a characteristic co a small coil of the Observe that its lor. Make . we wire by wrapping it around your pencil and place the wire coil in a cient powdered sulfur to completely cover the copper in the er and place the crucible on a clay triangle on an iron ring for heating. suffi crucible. Cov See Figure 3.3) THIS APPARATUS MUST BE SET UP AND ALL PROCEDURE PERFORMED IN THE HOOD because some sulfur will burn form noxious sulfur dioxide. Heat the crucible with a Bunsen burner initially with low heat on all sides; then use the hottest flame to heat the bottom of the crucible to red heat. Continue heating until no more smoking occurs, indicating that all the sulfur is bumed off. Using the crucible tongs, remove the crucible from the clay triangle without removing the cover and place it on a heat-resistant pad or wire gauze, not on the desktop, to cool. After the crucible has cooled, remove the cover and inspect the substance. Note its properties. Record your answers on the Report Sheet. GIVE IT SOME THOUGHT a. In this reaction, what is the limiting reactant? b. Which reactant is in excess? 1. Does the substance resemble copper? 2. Is it possible to bend the substance without breaking it? Handle it with tongs or forceps-not your fingers. 3. What color is it? 4. Has a reaction occurred? Copper(II) sulfide, CuS, is insoluble in aqueous ammonia, NH3 (aq) (that is does not react with NH3). whereas coppert) sulfide, Cu,S, dissolves (that is, does react) to give a blue solution with NH3. Place a small portion of your product in a test tube an 5. Does your product react with NH,? d add 2 mL of 6 MNH, in the hood. Heat gently with a Bunsen burner. n, Inc.Explanation / Answer
PartA
1) Substance does not resemble with copper. The copper metal is shiny and copper in color while product is black.
2) It is not possible to bend the product. It is brittle.
3) The product is a thick, gray-black coil.
4) The copper combined with sulfur and copper II sulphide is formed.
2 2Cu(s) + S(s) ----> Cu2S(s)
5) Yes, our product is reacted with liquid NH3 and forming the dark blue [Cu(NH3)4]2+ complex ion,
6) Possible formula for product is Cu2S
7)
16 Cu(s) + S8(s) = 8 Cu2S(s)
Part B
8) Zinc metal displaces the hydrogen from HCl to form hydrogen gas and zinc chloride. It is a single replacement reaction
9)
Zn(s) + 2HCl (aq) ------> ZnCl2(aq) + H2(g)
10) Cu(s) + HCl (aq) ------> no reaction.
Copper metal does displace hydrogen from HCl, because it is at a lower position than hydrogen in the electrochemical series.
11) Copper is an inactive metal
12) Test tube is filled with gas.
13) Brown color.
14) Formula for gas is NO2
Copper is oxidized by concentrated nitric acid, HNO3, to produce Cu2+ ions and the nitric acid is reduced to nitrogen dioxide.
Cu + 4HNO3 –> Cu(NO3)2 + 2NO2 + 2H2O
15) Water turns a green solution to a beautiful blue color and makes the brown gas disappear. Cu(NO3)2 is present.
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