Chemistry 103/113 Laboratory

 

 

This Week

Answer Keys

Gen Chem Lab

Periodic Table

 

 

 

·        Quantitative Characterization of a Cyanotyping Cmpd:  %Fe Analysis

Next Time

·       Expt: Build a Better Hot Pack

·       Quiz 5:  Photochemical Blues

 

Notes for Today

Problem:  What is mass % Fe3+ in the green solid?

 

           

 

Measuring g Fe (as g Fe3+)

·       Dissolve known mass of green solid in known volume of solution, convert all Fe3+ to Fe(L)x2+

·       Measure Absorbance of Fe(L)x2+ solution

·       A -> [Fe(L)x2+] (Beer’s Law)

·       [Fe(L)x2+] -> moles Fe(L)x2+

·       moles Fe(L)x2+ ->  moles Fe3+ ->  g Fe3+

 

 

Tasks for Today

·       Prepare Fe(L)x2+ standards, measure A (group)

·       Create Beer’s Law Plot (group)

·       Prepare solution of green solid and measure its g Fe (individuals)

 

 

New equipment

   

 

 

 

Spectrophotometer to

measure light absorbance

    

 

 

Volumetric flask for preparing

solutions of precisely known volume

 

      

 

 

 

Pipet and pipet pump for volume

measurements to +/- 0.01 mL

 

Safety Issues

·       Goggles required when preparing solutions.

·       Exercise caution with glass pipets

o   Gently insert end of pipet into pump.  Never use force.

o   Hold pipet securely, never by the pump.