I need help with question 3,5,6 please. Thank you Introduction An electrochemica

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I need help with question 3,5,6 please.
Thank you Introduction An electrochemical cell (a.k.a. galvanic cell, voltaic cell) is an apparatus that produces current via an oxidation-reduction (redox) reaction. Any household battery is an electrochemical cell that's been designed for use with common appliances and devices. Conversely, electrolysis uses current to cause a chemical reaction. In this lab, you will use electrolysis to experimentally determine the molar mass of lead. The current for the electrolysis will be supplied by a Cu-Zn electrochemical cell that you will assemble yourself The electrolytic cell will consist of two lead strips in a solution of lead (II) nitrate (see Figure 1). When a current is applied to this cell, the strip serving as the anode will lose mass as some of the lead is converted to lead (II) nitrate. Likewise, the cathode will gain mass as some of the lead (II) in solution is converted to metallic lead. If you know the amperage of the current applied, you can determine the number of electrons (in moles) transferred between the two electrodes while the cell was operational. The molar mass of the metal can be calculated by dividing the mass that was lost or gained at each electrode by the number of moles transferred during the reaction (ideally, the mass of lead lost at the anode should equal that gained at the cathode, but they probably won't due to experimental error). After the reaction has occurred, handling the two lead strips with care will help reduce the percent error of your experimental molar masses. Concepts to Review .Electrochemical cells · Oxidation-reduction reactions .Calculations with amperes Procedure . Obtain a strip of copper, a strip of zinc, and two lead stripes. Use sandpaper to clean each strip, removing any dirt and metal oxides that may have formed on the surface. The lead strips should be cleaned in a fume hood. 2. Using a scoopula or spatula, scratch a small mark on one of the lead strips and two small marks on th other 3. Weigh the two strips to the nearest milligram. 4. Assemble the apparatus shown in Figure las described below: a) Use copper wire to connect a zine strip to the lead strip with two marks. You can cut a small notch in each strip to avoid the wire from slipping off during the reaction b) Place the two lead strips in a 250 mL beaker and cover them with 0.5 M lead (II) nitrate, up to the point where you tied the wire (keep the wire out of the solution) c) Place the copper strip in another 250 mL beaker. Place the zinc in a porous cup, then place the cup in the same beaker as the copper strip. Fill the porous cup with 1.0 M copper (lI) sulfate, then add about 100 ml to the beaker iself. wire with an alligator clip on one end and a plug on the other (color doesn't matter). Clip one end of a wire to the lead strip with a single mark and plug the other end to the negative slot of the ammeter, which is usually a black on most of our ammeters)

Explanation / Answer

3 )

anode :    Pb(s) ------------------> Pb+2 (aq) + 2e-

cathode : Pb+2 (aq) + 2e- --------------> Pb (s)

6)

i = 14 A

t = 25 min = 25 x 60 = 1500 sec

E = equivalent weight = 50.9 / 3 = 16.97

F = faraday = 96485 C

from faraday laws

W = E x i x t / F

W = 16.97 x 14 x 1500 / 96485

W = 3.69 g

metal formed = 3.69 g

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