act2 presents

ACT2 Presents25 YEARS? That is Crazy!

• Roxie Allen• rallen@sjs.org• 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– rallen@sjs.org

ACT2 PresentsI’m ready for the next 25 YEARS!