ACT2 Presents25 YEARS? That is Crazy!
• Roxie Allen• [email protected]• St. John’s School• Houston, TX
• CAST 2009• Galveston, TX• November 6, 2009
How it all began
• Undergraduate degree in Biochemistry
• Decision to teach in college
• Brief Grad School
• MDAnderson Cancer Research
• Finally, teaching in Midland
The early years
• Teaching with my mentors
• Dan Kallus
• Ken Lyle
• Jack Hurst
Princeton 1990
Getting Involved Early
• ACT2, ChemEd, ACS, NSTA, CAST
–Going to Conferences
–Newsletter Editor
–Woodrow Wilson and Princeton
–Presenting at Conferences
Things I’ve gotten to do
• Teach amazing students
• Interact with phenomenal colleagues and friends
• Teach preservice teachers
• Spend summers in Colorado
• Travel abroad and all over the US
My favorite experiments
• Thermodynamics Experiments
• States of Matter Experiments
• Covalent Bonding Experiment
• Kinetics Experiments
Thermodynamics Part I
• Use principles of entropy to predict the spontaneity of a reaction
– Students use concepts of states of matter to determine if entropy is increasing
– Students predict if reaction may be spontaneous based ONLY on entropy
– Students visualize in the molecular level how changing state might change order and thus influence spontaneity
Part I Examples
• Reaction 2:
Cu(s) + 2 H+ (aq) Cu+2(aq) + H2(g)
• Reaction 3:
Ca+2(aq) + SO4-2(aq) CaSO4 (s)
Thermodynamics Part II
• Use the principles of reaction types to predict the spontaneity of a reaction
– Students have previously been given “rules” which govern reaction prediction
– Consider whether reaction is single replacement, double replacement, etc.
– Use solubility rules and reactivity series to predict spontaneity
Part II Examples
• Reaction 2:
Cu(s) + 2 H+ (aq) Cu+2(aq) + H2(g)
• Reaction 3:
Ca+2(aq) + SO4-2(aq) CaSO4 (s)
Thermodynamics Part III
• Student calculate Ho, So, and Go to determine the standard free energy change
• This brings the mathematical principles into the reaction prediction
• Students very often deal only with the math models, thinking it explains everything
Part III Examples
• Students calculate rxnHo , etc for each of the reactions.
• Some begin to contradict the predictions made in Part I and Part II.
• Students begin to question the spontaneity
• Students begin to wonder about the reactions
Thermodynamics Part VI
• Students perform the reactions in class
• Some occur as predicted, some don’t
• This is the macroscopic observation of the particulate theory
Thermodynamics Analysis
• For the analysis students write a paragraph for each reaction. They summarize the predictions and discrepancies.
• This lab allows for all types of learners to “see” thermodynamic principles for themselves
• This lab was originally found in JChemEd, but I’ve been unable to find a reference.
Heat of Vaporization of Nitrogen• This lab was originally written as a
thermochemistry lab for students to calculate the vapHo for liquid nitrogen.
• It is a fun lab, if you have a dewar
• Nitrogen is fairly cheap (~$1/L) and ten liters is enough for four classes
Heat of Vaporization of Nitrogen
• We extended the questions to include calculations of the boiling point of nitrogen, using the experimentally determined vapHo and a given vapSo
• Additionally we as questions regarding the driving forces for the reaction
Thermodynamics Lab 2Heat of Vaporization of Nitrogen• This lab is also from JChem Ed.
• Heat of Vaporization of Nitrogen
Peter Hamlet
JChem Ed Volume 64, 1987, p.1060
BOILING POINTS OF ORGANIC LIQUIDS WITH PASCO PROBES
• In this experiment you will determine the boiling point of several unknown organic liquids and attempt to identify the liquid from a list of possibilities, based on measured and accepted boiling points.
The Beral Pipet
BP Procedure
• Cut the tip off the pipet
• Use a Pasteur pipet to transfer liquid to be tested to the bulb of the Beral pipet
• Use a pin or paperclip to make a small pin-hole above the liquid level
• Put a boiling chip in the liquid
BP Procedure
• Insert a thermometer or a probe
• Lower the Beral pipet bulb into water in a beaker
• Warm the beaker on a hot plate
• Record the temperature as the liquid heats up.
Phase Diagram of CO2
• The purpose of this experiment is to witness the melting of dry ice and use crude instruments to determine the pressure of the triple point.
Phase Diagram of CO2
• Once again, a Beral pipet is used.
• Cut off the tip.
• Prepare a small transparent cup with tap water.
• Grind dry ice into a fine powder.
• Fill the base of the cut pipet with a small amount of dry ice
Phase Diagram of CO2
• Use pliers to clamp the pipet closed and lower the bulb into the water in the cup.
• Observe the dry ice carefully. As the pressure in the pipet builds, the ice will melt into a clear colorless liquid.
• Be CAREFUL! The ice can (and will) explode the pipet, but it is ok!
Phase Diagram of CO2
Molecular Modeling
• The purpose of this experiement is to introduce students to the concepts of Lewis Dot Structures, Valence Shell Electron Pair Repulsion Theory, and Hybridization and Types of Bonds in a hands-on concrete manner.
Molecular Modeling
• Part I: Lewis Dots– I teach the students to do Lewis Dot
Structures in class, then students spend the next one or two class periods working on their “25.”
– They finish them for homework.– These are then graded in class during
the following class period.
Molecular Modeling
• Part II: VSEPR– Models of the different possible
geometries are sketched, angles are measured and students choose from a list of names to identify with each model.
– These are corrected together– Students then go back to their “25” and
apply the names to them for HW
Molecular Modeling• Part III: Polarity
– Students are given two sets of models: one with polar molecules and one with non-polar molecules. They sketch them all.
– Students come up with a set of rules about what makes a molecule polar or non-polar.
– We discuss these in class to clear up misconceptions, then students apply them to their “25.”
Molecular Modeling
• Part IV: Hybridization and Bond Types– Students sketch hybrids – Students sketch molecules with sigma
and pi bonds– The sketches are discussed in class– Students go back to their “25” and
apply the rules they’ve learned.
Molecular Modeling
• Foundations of Chemistry Lab Manaul (WAY out of print, but awesome labs)
• Flinn Bonding ChemTopic Lab book has it also
Kinetic Study
• Investigate the factors that affect the rate of a reaction
–Nature of reactants
–Temperature
–Concentration
–Presence of a catalyst
Kinetic Study• I. oxalic acid solution reacts with
potassium permanganate solution
• H2C2O4 (aq) CO2 (g) + H2O (l) MnO4
- (aq) Mn2+ (aq)
•
• II. iron (II) sulfate solution reacts with potassium permanganate solution
• Fe+2 (aq) Fe3+ (aq) MnO4
- (aq) Mn2+ (aq)
Kinetic Study
• Beautiful colors • Concrete evidence
• JChem Ed sometime ago!
More and more labs
• I could go on and on with my favorite labs.
• I compiled labs into a lab manual, but I’ve no idea where most came from!
• I’m happy to share labs if you want.
Favorite Projects
• Name that Scientist Time Line
• Cations and Anions in Solution
• Chem Demos aka Santa’s Science Workshop
• Scavenger Hunt Power Point
Favorite Demos and Activities
• Hungry Dragon!
• Liquid Nitrogen Ice Cream
• Burning Paper with Steam
• Chemical Sunset
• Fire in the Hand!
• Giant Bunsen Burner
• Leaky Shower
Fun things to do
• Faraday Society
• ACS Chem Clubs
• National Chemistry Week
• If you want to purchase a 2G usb from ACT2 for $15, I’ll put my whole lab manual on it! Come to the ACT2 Sharathon Saturday Morning
• Email me if you want specific lab copies.– Roxie Allen– St. John’s School– [email protected]
ACT2 PresentsI’m ready for the next 25 YEARS!
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