Post on 24-Feb-2016
description
transcript
Macromedia Flash
Use of Macromedia Flash to Create a Web-based Tutorial for Inorganic Qualitative Analysis
ByPrem D. Sattsangi, Ph.D. and
†Christopher L. Byers (Programmer)
Chemtrek, by Stephen Thompson Solutions and Reactions
• Study of 14 Unknown (UK) aqueous solutions
– 12 Colorless UK
– 1 Blue UK (CuSO4)
– 1 Yellow UK (FeCl3)
Principles to be taught
• Acidity, Basicity, or Neutrality of Unknowns (UK)(Universal Indicator (UI) test)
• Water insolubility of reaction products (Binary-mixing of UK, to prepare an “Ion Reaction Chart”)
• Volatility of NH3(aq) (Compared to non-volatility of other basic samples, Na2CO3, Na3PO4, and NaOH)
An Economical and Eco-friendly Exercise
• UK samples, ~1.5 mL, are stored and used in *micropipets.(*~3 mL capacity plastic bulbs with a long stem) [*SAMCO TRANSFER PIPETS]
• Tests need only one drop of each reagent.
• Tests are performed over a plastic sheet cleaned by washing with water.
• Two students use one set.
Set of 16 UK Samples and reagents
Chemtrek, by Stephen Thompson
• pH test (UI)• Colored/colorless
samples• Soluble products• Insoluble precipitates
Digesting all this in ~ 1 hr, Pretty overwhelming!
First day of the lab
Ion Reaction Chart
Chemtrek
Expectations from the student:Identify a set of 8 unknownsUnknowns are selected from 17 colorless samples.6 out of 12 Samples used by students, 1 out of 2 *Cationsand 1 out of 4 *Anions. [*More challenging]
[Binary mix UK samples with 12 known solutions, comparewith the ion reaction chart for pH and solubility]
Identification, A formidable task!
Second day of the lab
Revised Approach “pH Tests”
• Colorless UKs only• pH test
First day of the labUniversal Indicator Test
TestUI
UK17Which Chart would
you like to go to?
6Acidic
7Neutral 4
Basic
Revised Approach “Chemical Reactions”
• Survey of insoluble precipitates• Writing chemical reactions
Develop a clear understanding of solubility rules and chemical reactions
First day of the lab(An abbreviated chart)
Revised Approach “The Roadmap”
Easy Identification
Second day of the labHCl, AlCl3, Pb(NO3)2, HNO3,
H2SO4, Al(NO3)3
HCl, H2SO4, HNO3
KI
(+) bubbles
(-) colorless (-) colorless(+) white ppt(+) yellow ppt(+) white ppt
AgNO3
BaCl2
AlCl3
AlCl3, Al(NO3)3
HCl H2SO4, HNO3 confirmed
Na2CO3
UK
AgNO3
(-) colorless(+) white ppt
H2SO4 HNO3
Pb(NO3)2
(+) gel, bubbles(+) white ppt
Al(NO3)3
Acidic Samples
Reagent
Improved Student Satisfaction
• Chemtrek Procedure:– Most students could identify 2-3 of the 8 UK samples
in the 3 hour lab.– Resulting in a frustrated class
• Roadmap Approach:– Most students identify all 8 UK samples in less than
an hour.– Remaining lab time is more profitably
used in writing chemical equations.View Flash