Question

Chemistry: Experimental Cell Potential Lab report

please help checking my work and answering question #2 #3 #4

Thanks!

*question #2 #3 #4*

Note that the ionic form of Ag is Ag' and of Fe is Fe Write a chemical reaction for each cell. For the reactants, choose the metal that was oxidized ion that was reduced spontaneously (i.e, a + potential) according to your data. (Thesethe elements!) Chemical reaction (oall) Cell notation (see text) (NA1 Zn(s)+Cu-Zn+Cu(s) r凸の, Zn(s) | Zn2 (aq) Il Cu(aq) Cu(s). ( 2n 12n ay fe .feusy Questions express potentials relative to another standard, for example, hydrogen. Given that Cu is 0.34v your The experimental potentials you have measured are all relative to copper. It is possible to 1. "above" hydrogen, you can put the potential for Cu relative to H2 on your number line. Use ative data to create a new number line showing each metal's potential relative to H2 instead of rol g page. to Cu (keeping the "distance" to Cu the same), and then fill in the table on the followin se Co Number line (relative to H2): Cu 0.34 H2 0.00 Spring19 Experimental potential Experimental potential Standard Reduction relative to H 17 R Metal Potential relative to Cu 0.90 Ag 6.A3 .66 0.13 Al 0.24 0.76 - 0.70 Zn 0.234 0.34 0.00 v Cu 2. will have a positive potential based on your experimental potential relative to Hz. Label each as a reduction of the metal by hydrogen or an oxidation of the metal by hydrogen ion. For example for the spontaneous reaction corresponding to the last row in the table above, Write a balanced reaction for each of the five metals with Hydrogen. Write the reaction so that it is a reduction of copper. H2 + Cu2+ → 2H+ + Cu solutions where materials are reduced by hydrogen. 3. Standard Potentials are defined for 1M Look up Standard Reduction Potentials in a textbook or in a handbook for each reaction with hydrogen and place them in the table above. (For Fe, be sure you use the value for Fe +2e → Fe, and not another half reaction) Compare the values and signs to yours. Which agrees best (other than Cu, which came from a reference)? Which has the poorest agreement? How does your number line on the previous page resemble the table of Standard Reduction Potentials... for order?... for values? 4. Each reaction in question 2 has a positive potential. If you looked up two Standard Reduction Potentials for two half cells of a different reaction, used them correctly to predict a cell potential, and that potential was a negative number, what does that mean about the spontaneity of the reaction? Of the reverse of the reaction that you wrote?

Answer 1

Answer 2

Row 1 Reaction with Ag

2Ag⁺ + H₂ ------> 2Ag + 2H⁺

Reduction of silver by hydrogen.

Row 2 Reaction with Al

2Al + 6H⁺ ------> 2Al³⁺ + 3H₂

Oxidation of Aluminum by hydrogen ion.

Row 3 Reaction with Fe

Fe + 2H⁺ ------> Fe²⁺ + H₂

Oxidation of iron by hydrogen ion.

Row 4 Reaction with Zn

Zn + 2H⁺ ------> Zn²⁺ + H₂

Oxidation of zinc by hydrogen ion.

Answer 3

Best Agreement : Silver (Ag⁺/Ag)

Poorest agreement : Aluminum (Al³⁺/Al)

Number line resembles for order as well as values except for Al and Fe.

Place for Fe is correct but its value is incorrect.

Actual place for Aluminum should be at the lowest point i.e. below Zinc.

Answer 4

If the cell potential is negative,

The spontaneity of the reaction : non-spontaneous

Reverse of the reaction : spontaneous (cell potential will be positive for reverse reaction).