Chemistry 103/113 Laboratory

 

 

This Week

Answer Keys

Gen Chem Lab

Periodic Table

 

 

 

·       Photochemical Blues (week 2)

·       Quiz 4:  Cu Cycle, Study Assignment E

 

Next Time

·       Expt: Quantitative Characterization of a Cyanotyping Cmpd, %Fe Analysis

 

Notes for Today

Qualitative Characterization

·       Precipitation tests for Cl-, Fe3+ and C2O42-

·       Flame test for K+

o   heat excites electrons to high E levels

o   as electrons drop back to lower E levels, photons of light are emitted

      

o   light color emitted is determined by element’s electron E level spacings

            

 

 

Cyanotyping

·       Coat paper with ferricyanide (safe!) and K3Fe(C2O4)3.3H2O mixture

·       Put opaque object or drawing over paper and expose to light

        

·       Fe3+ -> Fe2+

·       Why is light necessary?

·       Fe2+ reacts with ferricyanide to form a blue compound

 

·       Fix the blueprint to wash away unexposed photosensitive chemicals

    

 

Safety Issues

·       Splash hazard.  Goggles required.

·       Bunsen burner