1) Predict the products of electrolysis by filling in the graph:
Cl-, Br-, I-, H+, OH-, Cu2+, Pb2+, Ag+, K+, Na+,
2) Calculate the quantity of electrical charge needed to plate 1.386 mol Cr from an acidic solution of K2Cr2O7according to half-equation
H2Cr2O7(aq) + 12H+(aq) + 12e– → 2Cr(s) + 7 H2O(l)
3) Hydrogen peroxide, H2O2, can be manufactured by electrolysis of cold concentrated sulfuric acid. The reaction at the anode is
2H2SO4 → H2S2O8 + 2H+ + 2e–
When the resultant peroxydisulfuric acid, H2S2O8, is boiled at reduced pressure, it decomposes:
2H2O + H2S2O8 → 2H2SO4 + H2O2
Calculate the mass of hydrogen peroxide produced if a current of 0.893 flows for 1 hour.
4) The electrolysis of dissolved Cholride sample can be used to determine the amount of Chloride content in sample. At the cathode, the reduction half reaction is Cl2+(aq) + 2 e- -> 2 Cl-. What mass of Chloride can be deposited in 6.25 hours by a current of 1.11 A?
5) In an electrolytic cell the electrode at which the electrons enter the solution is called the ______ ; the chemical change that occurs at this electrode is called _______.
- anode, oxidation
- anode, reduction
- cathode, oxidation
- cathode, reduction
- cannot tell unless we know the species being oxidized and reduced.
6)How long (in hours) must a current of 5.0 amperes be maintained to electroplate 60 g of calcium from molten CaCl2?
- 27 hours
- 8.3 hours
- 11 hours
- 16 hours
- 5.9 hours
- 7) How long, in hours, would be required for the electroplating of 78 g of platinum from a solution of [PtCl6]2-, using an average current of 10 amperes at an 80% electrode efficiency?
8) How many faradays are required to reduce 1.00 g of aluminum(III) to the aluminum metal?
9) Find the standard cell potential for an electrochemical cell with the following cell reaction.
Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s)