Chemistry 104 Laboratory

 

 

This Week

Answer Keys

Gen Chem Lab

Periodic Table

 

 

 

á       Expt 9:  Electric Metal Art, Part I

 

Next Week

á       Expt 8:  Nanocrystalline Solar Cells

Notes for Today

Redox Rxn:  Zn(s) + 2 H+ (aq) --> Zn2+(aq)   + H2 (g)

  • reduction = gain of electrons: 2H+ + 2e- --> H2
  • oxidation = loss of electrons:  Zn --> Zn2+ + 2e-
  • reducing agent is oxidized and is the source of e-: Zn
  • oxidizing agent is reduced and is the acceptor of e-: H+

 

Electrochemical Cell Based on the Rxn: Zn(s) + 2H+ (aq) --> Zn2+(aq)   + H2 (g)

      

  • anode = electrode where e- are generated
  • cathode = electrode where e- are consumed

 

Cell Notation: Zn(s)| Zn2+(aq) || H+ (aq)| H2 (g)| Pt

  • left to right:  oxidation half cell || reduction half cell
  • | = surface or phase change; || = salt bridge

 

 

Current Flow Within the Cell

  • must be a complete circuit
  • e- movement in electrical conductors (wire/electrodes)
  • ion movement in solution (salt bridge/half cell solution)

       

 

 

Electrochemical Cell Type

 

Calculating the Standard Cell Potential

 

 

Time Management

  • Sketch and write equations as you work.

Safety

  • Recycle reagents in designated containers.
  • Goggles Required