CHEM 1A Study Guide - Midterm Guide: Standard Hydrogen Electrode, Galvanic Cell, Periodic Trends
Get access
Related textbook solutions
Chemistry: Structure and Properties
Basic Chemistry
Principles of Chemistry Molecular Approach
Chemistry: Structure and Properties
Principles of Chemistry Molecular Approach
Chemistry: A Molecular Approach
Chemistry: A Molecular Approach
Principles of Chemistry: A Molecular Approach
Chemistry: The Central Science
Related Documents
Related Questions
The saturated calomel electrode, abbreviated SCE, is often used as a reference electrode in making electrochemical measurements. The SCE is composed of mercury in contact with a saturated solution of calomel Hg2Cl2. The electrolyte solution is KCl. ESCE is +0.242 V relative to standard hydrogen electrode.
Calculate the potential for each of the galvanic cells containing a saturated calomel electrode and the given half-cell components at standard conditions. In each case indicate whether the SCE is the cathode or the anode. Standard reduction potentials are found in table:
Electrode |
SCE |
a) Cu2+ + 2e- → Cu | b) Fe3+ + e- → Fe2+ | c) AgCl + e- → Ag + Cl- | d) Al3+ + 3e- → Al | e) Ni2+ + 2e- → Ni |
Eo |
+0.242 V |
+ 0.339 V | + 0.771 V | + 0.223 V | - 1.677 V | - 0.257 V |
1. Consider a voltaic (galvanic) cell with the following metal electrodes. Identify which metal is the cathode and which is the anode, and calculate the cell potential.
(a) Al and Co(II)
Cathode: ____
Anode: ______
Ecell =
(b) Cd(II) and Ag(I)
cathode: ___
anode: ___
Ecell= ____
(c) Cr(III) and Sc(III)
cathode: ___
Anode:_____
Ecell:____
2. A voltaic cell contains two half-cells. One half-cell contains a titanium electrode immersed in a 1.00 M Ti(NO3)3 solution. The second half-cell contains a zinc electrode immersed in a 1.00 M Zn(NO3)2 solution.
Ti3+(aq) + 3 eâ â Ti(s) | Eâ°redâ = â1.370 V |
Zn2+(aq) + 2 eâ â Zn(s) | Eâ°redâ = â0.762 V |
(a) Using the standard reduction potentials given above, predict the standard cell potential of the voltaic cell.
(b) Write the overall balanced equation for the voltaic cell. (Include states-of-matter under the given conditions in your answer.)
3. ÎG° and E° can be said to measure the same thing, and are convertible by the equation
ÎG° = ânFEâ°cellâ
where n is the total number of moles of electrons being transferred, and F is the Faraday constant 9.64853415âââ104 C/mol. The free energy (ÎG°) of a spontaneous reaction is always negative.
For each of the electrochemical cells below, calculate the free energy of the system and state whether the reaction is spontaneous or non-spontaneous as written based on the cathode and anode assignment given. (Use the table of Standard Electrode Potentials.)
(a) The cathode is Zn(II) and the anode is Co(II).
free energy: ____ kJ
spontaneity: _____