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