Suggested Demos for March 18-24th

 Hello Professors!!!

We are back from break, and these are the hottest and trendiest demonstrations for the upcoming week!

The chemicals are absolutely flying off the shelves, so order while you can!

 

Here is the link (Password: hydrogen) to order as well as the full list of demos; as always, early orders are very appreciated!

 

General Chemistry I:

 

Weekly topics

  • Molecular Geometry and Bonding Theories

 

Suggested Demonstrations

 

Polarity and Geometry –  Show the dependence of dipole-dipole forces on geometry by contrasting the effect of a charged rod on streams of H2O and “CCl4” (actually hexane) flowing from burets.

Paramagnetic O2 – Demonstrate the paramagnetism of liquid oxygen by pouring first N2(ℓ), then O2(ℓ) between the poles of a powerful magnet on the overhead projector or document camera.

VSEPR Models – Use ball-and-stick models to illustrate the VSEPR shapes and sub-shapes. Normal order is for the parent shapes. You must specify if you want subshapes

 

General Chemistry II:

 

Weekly topics

  • Chemical Thermodynamics
  • Periodic trends and Gases

 

Suggested Demonstrations

 

Money to Burn – Soak a dollar bill in a water-alcohol mixture and then light it with a match; the high specific heat of water keeps the combustion temperature low enough to prevent burning the bill

An Endothermic Reaction – Shake solid Ba(OH)2 8 H2O with solid NH4NO3 to produce an aqueous mixture of Ba(NO3)2 (s) and NH3 (aq). The reaction is endothermic enough to freeze the flask to a wet piece of cardboard.  Alternatively, a digital thermometer can be used to record the temperature change

Thermite – Perform the thermite reaction, in which Al and Fe 2O 3 react to produce molten iron.

i) NOTE: 48 hour notice is required for this demonstration

 Combustion of Ethanol Vapors – Allow a small amount of ethanol to vaporize in a large

carboy, pour out the excess liquid, and hold a lighted splint to the mouth of the container – the impressive reaction also demonstrates the explosive flammability of organic vapors

 

Periodic Properties – Add pieces of Li, Na, K, Mg, and Ca, to beakers of water and

phenolphthalein to observe the reactivity of metals from different parts of the periodic table. If desired, you can add HCl to those beakers where no reaction occurred

Halogens – Display flasks containing the halogens chlorine, bromine, and iodine.

i) On request, you can order a special flask of bromine that can be frozen in liquid nitrogen

 

General Chemistry for Engineers:

 

Weekly topics

  • Energy & Entropy
  • 2nd and 3rd law of thermodynamics

 

Suggested Demonstrations 

 

Money to Burn – Soak a dollar bill in a water-alcohol mixture and then light it with a match; the high specific heat of water keeps the combustion temperature low enough to prevent burning the bill

An Endothermic Reaction – Shake solid Ba(OH)2 8 H2O with solid NH4NO3 to produce an aqueous mixture of Ba(NO3)2 (s) and NH3 (aq). The reaction is endothermic enough to freeze the flask to a wet piece of cardboard.  Alternatively, a digital thermometer can be used to record the temperature change

Thermite – Perform the thermite reaction, in which Al and Fe 2O 3 react to produce molten iron.

i) NOTE: 48 hour notice is required for this demonstration

 Combustion of Ethanol Vapors – Allow a small amount of ethanol to vaporize in a large

carboy, pour out the excess liquid, and hold a lighted splint to the mouth of the container – the impressive reaction also demonstrates the explosive flammability of organic vapors

 

 

 

Elementary Chemistry:

 

Weekly topics

  • Gases/Liquids/Solids
  • Intermolecular forces
  • Solutions/Solubility
  • Concentration/Dilution
  • Osmosis/Diffusion
  • Cell membrane

 

Suggested Demonstrations

 

Charles’ Law – Pour liquid nitrogen over a balloon to show that a decrease in T is accompanied by a decrease in V.

Like Dissolves Like – Contrast the solubility of I2 (s) and CuCl2 (s) in both water and hexane in large test tubes.

Osmotic Pressure – Small dialysis bags containing equimolar solutions of isopropanol and CaCl2 are attached to long glass tubes; immerse the bags in distilled water to illustrate osmosis and to show that osmotic pressure depends on the number of particles in solution.

Polarity and Solubility – Add acetone to a saturated solution of CuSO4 (aq) causing CuSO4 (s) to crystallize out – the solubility of CuSO4 decreases as the polarity of the solvent is decreased.

Ammonia Fountain – Show the solubility of NH3 (g) in H2O due to hydrogen-bonding.

Boiling Water at Room Temperature – Show water boiling at room temperature in a beaker in an evacuated bell jar, then put your hand in the water after boiling to convince students of its low temperature.

 

 

 

Foundations of General Chemistry:

 

Weekly topics

  • Ideal/real gas law
  • Mixtures & partial pressures
  • Effusion/diffusion

 

Suggested Demonstrations

 

Charles’ Law – Pour liquid nitrogen over a balloon to show that a decrease in T is accompanied by a decrease in V.

Graham’s Law of Diffusion – Allow concentrated NH3 and concentrated HCl to vaporize and meet in a horizontal glass tube, forming a ring of NH4Cl.

Marshmallow Snowman – Demonstrate the effect a decrease in P has on V by placing a marshmallow snowman in a bell jar and then evacuate the jar.

Squashing Pop Cans with Atmospheric Pressure – Use atmospheric pressure to squash pop cans.

 

Thank you and have a great week!

The Demo Lab 

 

PS if you are ahead/behind of schedule let us know so we can adjust the demos accordingly. Currently we are simply using the syllabi to guess where your respective classes are at.  And here is the link again 🙂: Demo Ordering Link

Suggested Demos for March 4th-8th

Hello Professors!!!

Today is Thursday, February 29th…  

With spring break almost upon us, we recommend treating your students to one of our particularly exciting demonstrations to “burn” the concepts in their mind before the break. These include: 

Thermite 

Potassium permanganate/glycerin 

Combustion of magnesium in dry ice 

H2/O2 Balloon series 

Or any of our other Fire Friday Demos 

…And these are the hottest and trendiest demonstrations for the upcoming week! 

The chemicals are absolutely flying off the shelves, so order while you can!  

 

Here is the link (Password: hydrogen) to order as well as the full list of demos; as always, early orders are very appreciated! 

 

General Chemistry I:  

 

Weekly topics –Basic Concepts of Chemical Bonding 

 

Suggested Demonstrations 

 

Contrast models of NH2—NH2, NH=NH, and N≡N to show the decreasing N–N bond length as the bond order increases 

 

General Chemistry II:  

  

Weekly topics  

-Mechanisms and Catalysis 

-Additional Aspects of Aqueous equilibria 

 

Suggested Demonstrations  

Catalysis of a Reaction – Demonstrate the catalysis of the H2O 2 decomposition of NaK- 

tartrate with Co 2+. Adding Co 2+ turns the solution pink, but the solution quickly turns dark green as it begins to react vigorously. At the end of the reaction, the pink color is restored showing regeneration of the catalyst 

Elephant Toothpaste – Demonstrate the decomposition of 30% H2O 2 in the presence of 

dishwashing liquid and KI, producing an upsurge of steaming foam 

 

 

Iodine Clock Reaction – Perform the iodine clock reaction with three different initial concentrations of IO3 

Catalysis of a Reaction – Demonstrate the catalysis of the H2O2 decomposition of NaK-tartrate with Co2+. Adding Co2+ turns the solution pink, but the solution quickly turns dark green as it begins to react vigorously. At the end of the reaction, the pink color is restored showing regeneration of the catalyst 

Briggs-Rauscher Oscillating Reaction – Introduce the mystery of mechanisms with the Briggs-Rauscher Oscillating Reaction. 

 

Buffer Capacity Demo – Contrast the buffer capacity of water, 1 M CH3COOH/NaCH3COO, and 0.1 M CH3COOH/NaCH3COO by adding increments of 6 M HCl to each in the presence of an indicator 

Common Ion Effect Demos HCl/NaCl – add concentrated HCl (aq) to saturated NaCl(aq) to cause precipitation of NaCl (s)  

 

  

General Chemistry for Engineers:  

  

Weekly topics  

 -Energy and Chemistry 

 

Suggested Demonstrations  

 

An Endothermic Reaction – Shake solid Ba(OH)2 8 H2O with solid NH4NO3 to produce an aqueous mixture of Ba(NO3)2 (s) and NH3 (aq). The reaction is endothermic enough to freeze the flask to a wet piece of cardboard.  Alternatively, a digital thermometer can be used to record the temperature change 

Thermite – Perform the thermite reaction, in which Al and Fe 2O 3 react to produce molten iron. 

Glycerin and Potassium Permanganate – Pour glycerin over KMnO 4 (s) to initiate a 

spontaneous combustion accompanied by smoke, sparks, and a lavender flame. 

 

 

Elementary Chemistry:  

  

Weekly topics  

-Gases and IMFs 

  

Suggested Demonstrations  

 

Lake Nyos Demo – Pour CO 2 (g) down an enclosed set of steps to extinguish candles 

on each step, demonstrating the fluidity of gases, and recreating (on a small scale) a 

tragic natural disaster 

 

Halogens – Display flasks containing the halogens chlorine, bromine, and iodine. 

  1. i) On request, you can order a special flask of bromine that can be frozen in liquid nitrogen

 

Use pairs of space-filling models of n-pentane and isopentane to show that increased 

branching increases compactness, decreases polarizability, and decreases London forces 

  1. i) Pair with velcro models to simulate the strength of IMF between branched and un-

branched hydrocarbons 

 

 Foundations of General Chemistry:  

  

Weekly topics  

 – Thermochemistry 

 

Suggested Demonstrations  

 

Hot and Cold Packs – Combine NH4NO3 (s) and water in a Ziploc bag to make an instant “cold pack”. Combine CaCl2(s) and water to make an instant “hot pack” 

Thermite – Perform the thermite reaction, in which Al and Fe 2O 3 react to produce molten iron. 

An Endothermic Reaction – Shake solid Ba(OH)2 • 8 H2O with solid NH4NO3 to produce an aqueous mixture of Ba(NO3)2 (s) and NH3 (aq). The reaction is endothermic enough to freeze the flask to a wet piece of cardboard. Alternatively, a digital thermometer can be used to record the temperature change 

Thionine Reaction – Hold a solution of thionine and FeSO4 in front of a bright light to show the reduction of thionine from a violet form to a colorless form; this is an endothermic reaction that absorbs light energy. 

Luminol – Pour solutions of luminol and H2O2 into a tall glass spiral to produce a beautiful chemiluminescent reaction. The light-emitting species is the dicarboxylate ion, aminophthalate, the product of the oxidation of luminol with H2O2 

Combustion of Candy – Contrast the oxidation of sucrose in the body (by eating some candy) with the oxidation of sucrose by KClO3 (as shown by dropping some candy into molten KClO3, producing steam and a lavender flame. The body temperature is ~37°C, and the melting point of KClO3 is 368°C. 

 

 

 

Thank you and have a great week!  

The Demo Lab  

  

PS if you are ahead/behind of schedule let us know so we can adjust the demos accordingly. Currently we are simply using the syllabi to guess where your respective classes are at.  And here is the link again 🙂: Demo Ordering Link
 

 

 

Kind regards, 

 

Lynda Reynolds 

 

Suggested Demos for Feb.19-23rd

Hello Professors!

Today is Thursday, February 15th (happy belated Valentines Day!), and these are the hottest and trendiest demonstrations for the upcoming week! 

The chemicals are absolutely flying off the shelves, so order while you can!  

Here is the link (Password: hydrogen) to order as well as the full list of demos; as always, early orders are very appreciated! 

  

General Chemistry I:  

  

Weekly topics  

-Chemistry Electronic Structure of Atoms 

  

Suggested Demonstrations 

 

Gas Discharge Tubes of the Noble Gases – show that different gases give different colors when subjected to an electric discharge (H2 tube also available) 

 

Atomic Spectra: Flame Tests – Introduce various metal salts (e.g. NaCl, SrCl2, CuCl2) into an open flame to produce brilliant colors associated with exciting metal cations. 

 

Pickle Electrocutor – Run an electric current through a dill pickle using a special apparatus to show students that the brine in the pickle conducts electricity, and the current heats and excites the sodium atoms present to a higher energy level. The emission of photons as the sodium returns to the ground state accounts for the yellow color of the light. 

 

General Chemistry II:  

  

Weekly topics  

-Acid/base equilibria 

-Electrochemistry 

  

Suggested Demonstrations  

Le Chatelier’s Principle: Iron (III) Thiocyanate Equilibria – Apply stress to the Fe3+ + SCN- → FeSCN2+ system in five different ways to show the equilibrium shifts accompanying changes in the concentration of reactants.  

Acidic and Basic Oxides – Dissolve several oxides (CaO, ZnO, CO2, P4O10) in water containing universal indicator to show a range of basic and acidic oxides 

Yamada and Dry Ice – Add a chunk of dry ice to a 2 L cylinder containing a basic solution and Yamada universal indicator; the dry ice gradually acidifies the solution causing the color to change in the order purple, blue, green, yellow, orange.  

Concentration Cell – Set up a concentration cell with 1 M Cu 2+ on the bottom and 

0.01 M Cu 2+ on the top with copper plates immersed in the solutions as electrodes; the 

voltage read from a multimeter should be close to 59 mV as predicted by the Nernst equation 

Electrolysis of Water – Electrolyze water (dilute Na2SO4 solution with indicator) in the Hoffman apparatus to decompose it into its component elements, hydrogen and oxygen. If desired, you can test the H2 (g) and/or O2 (g) produced with a flame and a glowing splint, respectively. 

  

 

 

General Chemistry for Engineers:  

  

Weekly topics  

-Chemical Bonding and Molecular Structure 

-Molecules and Materials 

  

Suggested Demonstrations  

 

 

Models: Contrast models of NH2—NH2, NH=NH, and N≡N to show the decreasing N–N bond length as the bond order increases 

Polarity and Geometry – Show the dependence of dipole-dipole forces on geometry by contrasting the effect of a charged rod on streams of H2O and “CCl4” (actually hexane) flowing from burets 

Paramagnetic O2 – Demonstrate the paramagnetism of liquid oxygen by pouring first N2(ℓ), then O2(ℓ) between the poles of a powerful magnet on the overhead projector or document camera. 

 

Nylon 6-10 – Demonstrate the polymerization of hexamethylenediamine with sebacoyl 

chloride to produce the polyamide Nylon 6-10. 

Covalent Network Solids – show large models of different arrangements of pure carbon: graphite, 

diamond, and/or C60 (buckminsterfullerene). 

Crystalline and Amorphous Solids – contrast a piece of charcoal, a large quartz crystal, a piece of pumice, and a polished quartz crystal (SiO 2). 

 

We’ve also got all the crystal structures of metals and materials, there are just too many to put here.  

 

Elementary Chemistry:  

  

Weekly topics  

-Chemical Reactions 

-Carbohydrates 

  

Suggested Demonstrations  

 

Oxidation of AlcoholsDemonstrate the oxidation of ethanol with K2Cr2O7 on the overhead projector; the alcohol solution changes from orange to green to blue as the Cr(VI) is reduced; this reaction is the basis for the Breathalyzer test. 

 Ammonium Dichromate Volcano – Ignite a pile of (NH4)2Cr2O7 volcano in an aquarium to produce N2 (g), H2O (g), and Cr2O3 (s). The resulting reaction looks very much like an erupting volcano. 

 

 

Combustion of Candy– Contrast the rate of oxidation of sucrose in the body (by eating 

some candy) with the oxidation of sucrose by KClO 3 (as shown by dropping some candy 

into molten KClO 3, producing steam and a lavender flame. Body temperature is ~37C, 

and the melting point of KClO 3 is 368C. 

Disaccharides – Display a large plastic Darling model of sucrose 

Black Carbon Snake – add concentrated H2SO 4 to sugar in a tall beaker to produce a 

black “snake” of carbon that grows out the top of the beaker. 

 

 

 Foundations of General Chemistry:  

  

Weekly topics  

-Solutions and aqueous reactions 

  

Suggested Demonstrations  

 

Crystallization of Supersaturated Sodium Acetate Solution – Add a tiny crystal of sodium acetate to a 2 L flask of a super-saturated solution to cause the solid to crystallize out, leaving almost no liquid – this demonstration is beautiful and dramatic, as well as being quite exothermic. Alternatively, you can pour the solution slowly over a single crystal to build up a column of solid sodium acetate 

 

Yamada and Dry Ice – Add a chunk of dry ice to a 2 L cylinder containing a basic solution and Yamada universal indicator; the dry ice gradually acidifies the solution causing the color to change in the order purple, blue, green, yellow, orange 

 

Electrolysis of Water – Electrolyze water (dilute Na2SO4 solution with indicator) in the Hoffman apparatus to decompose it into its component elements, hydrogen and oxygen. If desired, you can test the H2 (g) and/or O2 (g) produced with a flame and a glowing splint, respectively. 

 

The Tyndall Effect – Demonstrate the Tyndall effect and simulate a sunset on the overhead projector by reacting Na2S2O3 with HCl to produce a colloidal suspension of sulfur. 

 

 

Thank you and have a great week!  

-The Demo Lab  

  

PS if you are ahead/behind of schedule let us know so we can adjust the demos accordingly. Currently we are simply using the syllabi to guess where your respective classes are at.  and here is the link again 🙂: Demo Ordering Link
 

 

 

Kind regards, 

 

Lynda Reynolds 

Suggested Demos For Organic Chemistry Lecturers

 

 

Hello Organic Chemistry Professors!  

The following is a compilation of some of the most popular demonstrations we offer for organic chemistry courses.  

We hope this can serve as a guide for the semester and are currently working on some projects to better bring the mechanisms of the 2520 classes to life!  

For our 2310/2510 classes, you may find our large models (cyclohexane configurations, chirality, etc.) to be particularly helpful for establishing the basics, as well as our limonene demonstration of chirality and light (my personal favorite).   

For our 2520/1920 classes, we have several options which show how the mechanistic concepts are utilized in real life (polymerization, breathalyzers, etc.).  

 

Here is the link (Password: hydrogen) to order as well as the full list of demos; as always, early orders are very appreciated, and we can make more models than the ones explicitly stated on the website! 

  

Demonstrations:  

  Structural Models  

Empirical Formulas from Analyses 

  1. a) Show ball-and-stick models to match empirical and molecular formulas derived in lecture:
  2. i) C6H6 and/or C2H2 from CH
  3. ii) Any cycloalkane or alkene from CH2

 

Representations of Orbitals 

  1. a) Show models of s, p, d, and f orbitals
  2. b) Show large Styrofoam balls in two sizes to represent the 1s and 2s orbitals and a large

Styrofoam model of the 2p subshell 

  1. c) Show a large Styrofoam model of the 2s and 2p orbitals nestled together in contrasting colors
  2. d) Show a Styrofoam hemisphere painted to represent a cross-sectional view of the probability

distribution of electron density inside a 2s orbital 

 

Molecular Orbital Theory 

  1. a) To help students visualize how p orbitals interact to form molecular orbitals, use a large

Styrofoam model of the p subshell and a large Styrofoam model of a p orbital (show two p 

orbitals end-to-end and then two parallel p orbitals along the y axis or the z axis), or use two 

small models (side-by-side) of the p subshell (px, py, and pz) 

  1. b) Contrast models of NH2—NH2, NH=NH, and N≡N to show the decreasing N–N bond length as

the bond order increases 

  1. c) Paramagnetic O 2 – Demonstrate the paramagnetism of liquid oxygen by pouring first N2(ℓ),

then O 2(ℓ) between the poles of a powerful magnet displayed by the document camera. 

 

Newman Projections 

(1) Use the Newman projection device to show eclipsed and staggered views of a 

simple alkane 

 

Cycloalkanes 

  1. i) Show Darling models of cyclopropane, cyclobutane, cyclopentane, and cyclohexane
  2. ii) Display one (or two) extra-large Darling model of cyclohexane and define the terms axial

and equatorial 

iii) Show two models of cyclohexane to contrast the chair and boat conformations 

  1. iv) Pass around Darling models of cyclohexane so students can appreciate its unique

structure and contrast the chair and boat conformations for themselves 

  1. v) Add colored substituents to two models of a cycloalkane to show cis and trans isomers

 

Organic Chemical Reactions 

Polymeric Solids 

  1. a) Disappearing Styrofoam Cup – Make a Styrofoam (expanded polystyrene) cup disappear by

placing it in a dish of acetone. 

 

  1. b) Nylon 6-10 – Demonstrate the polymerization of hexamethylenediamine with sebacoyl

chloride to produce the polyamide Nylon 6-10. 

  1. c) Cross-linking Polymers

 

  1. i) Disposable Diaper Demo – See how much water you can add to a super-absorbent

disposable diaper, then cut open another diaper to show the super-absorbent powder, 

Water Lock J-550, which is polysodium acrylate cross-linked with starch; the original 

polymer results from multiple addition reactions of the alkene functional groups of acrylic 

acid molecules. (One diaper holds 1 L of water!) 

 

  1. ii) Slime! – make a cross-linked gel by mixing solutions of polyvinyl alcohol and borax; use

this demo to relate concepts such as polymers and hydrogen-bonding to a commercial 

product students are familiar with 

 

Reaction Mechanisms 

  1. a) Briggs-Rauscher Oscillating Reaction – Introduce the mystery of mechanisms with the Briggs-Rauscher Oscillating Reaction.

 

  1. b) A Simple Oscillating Reaction – Based on the B-Z oscillating reaction, solutes are added in sequence to produce a red-colorless oscillating reaction. This is an alternative to the Briggs- Rauscher reaction, as it does not produce iodine.

 

  1. c) Oscillating Methanol Explosion – A platinum wire is heated in a flask containing methanol, creating a small explosion that deprives the local environment of oxygen. As more oxygen diffuses in, the platinum wire heats again, causing another explosion

 

Unnamed: To show the unlikelihood of a termolecular collision, give colored foam balls to three students and challenge them to throw the balls so that all three collide simultaneously 

 

Oxidation of AlcoholsDemonstrate the oxidation of ethanol with K2Cr2O7 on the overhead projector; the alcohol solution changes from orange to green to blue as the Cr(VI) is reduced; this reaction is the basis for the Breathalyzer test. 

 

Combustion of Ethanol Vapors – Allow a small amount of ethanol to vaporize in a large 

carboy, pour out the excess liquid, and hold a lighted splint to the mouth of the container 

– the impressive reaction also demonstrates the flammability of organic vapors 

 

Oxidation and Reduction of Aldehydes and Ketones 

  1. i) Tollen’s Test: Silver Mirror – Create a silver coating inside a small Erlenmeyer flask

using Tollen’s reagent and an aldehyde solution. 

  1. ii) Benedict’s Test – Use Benedict’s solution and dextrose to demonstrate Benedict’s test

for aldehydes. Different sugars are available upon request. 

 

Chirality (models and chemicals) 

 Optical isomerism 

  1. i) Show pairs of MA 2B 2 or MA 3 enantiomers, where A is bidentate; use a large mirror with

the models to help explain the concept of non-superimposable mirror images 

 

  1. ii) Polarizing Filters and Limonene – Place small beakers of (R)-(+)-limonene and (S)-(-)-

limonene between two polaroid sheets on the overhead projector to show the equal but 

opposite rotation of plane-polarized light by these enantiomers; you can also show that a 

racemic mixture does not rotate polarized light 

 

Molecular Chirality 

(1) Use a large mirror and a pair of enantiomeric models (R- and S- CHBrClF) to explain 

the concept of non-superimposable mirror images; 

 

(2) Show two models of CH4, two models of CH3Cl, two models of CH2Cl2, two models of 

CH2ClBr, and an enantiomeric pair of CHBrClF models to contrast superimposable 

and nonsuperimposable mirror images; you can also point out the planes of 

symmetry that exist in all the models except CHBrClF. 

 

Properties of Enantiomers 

  1. i) Pass scent samples of (S)-(+)-carvone (odor of caraway) and (R)-(-)-carvone (odor of

spearmint) around the class so students can experience the dramatic difference in the 

odors of these enantiomers 

 

We will send this out again in a few weeks as a reminder. Additionally, there will be another one for the fall. We are hoping to integrate the demo lab better with the organic chemistry curriculum here so all suggestions are welcome! 

 

Thank you and have a semester!  

-The Demo Lab  

  

Here is the link again 🙂: Demo Ordering Link 

Hello Professors!

Today is Thursday, February 8th, and these are the hottest and trendiest demonstrations for the upcoming week! 

The chemicals are absolutely flying off the shelves, so order while you can!  

Here is the link (Password: hydrogen) to order as well as the full list of demos; as always, early orders are very appreciated! 

  

  

General Chemistry I:  

  

Weekly topics  

-Thermochemistry 

  

Suggested Demonstrations 

Hot and Cold Packs – Combine NH4NO3 (s) and water in a Ziploc bag to make an instant “cold pack”. 

 

Thermite – Perform the thermite reaction, in which Al and Fe2O3 react to produce molten iron.
NOTE: 48 hour notice is required for this demonstration 

 

Combustion of Ethanol Vapors – Allow a small amount of ethanol to vaporize in a large carboy, pour out the excess liquid, and hold a lighted splint to the mouth of the container – the impressive reaction also demonstrates the explosive flammability of organic vapors.  

 

Ammonium Dichromate Volcano – Ignite a pile of (NH4)2Cr2O7 volcano in an aquarium to produce N2 (g), H2O (g), and Cr2O3 (s). The resulting reaction looks very much like an erupting volcano. 

 

 

 

General Chemistry II:  

  

Weekly topics  

-Acid/base equilibria 

-Redox Reactions 

-Electrochemistry 

  

Suggested Demonstrations  

Le Chatelier’s Principle: Iron (III) Thiocyanate Equilibria – Apply stress to the Fe3+ + SCN- → FeSCN2+ system in five different ways to show the equilibrium shifts accompanying changes in the concentration of reactants.  

Yamada and Dry Ice – Add a chunk of dry ice to a 2 L cylinder containing a basic solution and Yamada universal indicator; the dry ice gradually acidifies the solution causing the color to change in the order purple, blue, green, yellow, orange.  

Concentration Cell – Set up a concentration cell with 1 M Cu 2+ on the bottom and 

0.01 M Cu 2+ on the top with copper plates immersed in the solutions as electrodes; the 

voltage read from a multimeter should be close to 59 mV as predicted by the Nernst equation 

Electrolysis of Water – Electrolyze water (dilute Na2SO4 solution with indicator) in the Hoffman apparatus to decompose it into its component elements, hydrogen and oxygen. If desired, you can test the H2 (g) and/or O2 (g) produced with a flame and a glowing splint, respectively. 

 

General Chemistry for Engineers:  

Weekly topics  

-The Periodic Table and Atomic Structure 

-Chemical Bonding and Molecular Structure 

  

Suggested Demonstrations (please electrocute the pickle) 

 

 

Gas Discharge Tubes of the Noble Gases show that different gases give different colors when subjected to an electric discharge (H2 tube also available) 

Fireworks Balloons – Show the brilliant colors of metal cations in a fun way by igniting hydrogen balloons containing metal salts. 

 Pickle Electrocutor – Run an electric current through a dill pickle using a special apparatus to show students that the brine in the pickle conducts electricity, and the current heats and excites the sodium atoms present to a higher energy level. The emission of photons as the sodium returns to the ground state accounts for the yellow color of the light. 

Models: Contrast models of NH2—NH2, NH=NH, and N≡N to show the decreasing N–N bond length as the bond order increases 

Polarity and Geometry – Show the dependence of dipole-dipole forces on geometry by contrasting the effect of a charged rod on streams of H2O and “CCl4” (actually hexane) flowing from burets 

Paramagnetic O2 – Demonstrate the paramagnetism of liquid oxygen by pouring first N2(ℓ), then O2(ℓ) between the poles of a powerful magnet on the overhead projector or document camera. 

 

 

 

Elementary Chemistry:  

  

Weekly topics  

-Organic Compounds 

-Chemical Reactions 

  

Suggested Demonstrations  

 

Disappearing Styrofoam CupMake a Styrofoam (expanded polystyrene) cup disappear by placing it in a dish of acetone. 

Miscibility and Immiscibility Mix ethanol and colored water in one beaker and hexane and colored water in another to demonstrate miscibility and immiscibility due to differences in the intermolecular forces of alcohols as the size of the alkyl group increases. 

Oxidation of AlcoholsDemonstrate the oxidation of ethanol with K2Cr2O7 on the overhead projector; the alcohol solution changes from orange to green to blue as the Cr(VI) is reduced; this reaction is the basis for the Breathalyzer test. 

 Ammonium Dichromate Volcano – Ignite a pile of (NH4)2Cr2O7 volcano in an aquarium to produce N2 (g), H2O (g), and Cr2O3 (s). The resulting reaction looks very much like an erupting volcano. 

 

 

 

 Foundations of General Chemistry:  

  

Weekly topics  

-Solutions and aqueous reactions 

  

Suggested Demonstrations  

 

Crystallization of Supersaturated Sodium Acetate Solution – Add a tiny crystal of sodium acetate to a 2 L flask of a super-saturated solution to cause the solid to crystallize out, leaving almost no liquid – this demonstration is beautiful and dramatic, as well as being quite exothermic. Alternatively, you can pour the solution slowly over a single crystal to build up a column of solid sodium acetate 

 

Yamada and Dry Ice – Add a chunk of dry ice to a 2 L cylinder containing a basic solution and Yamada universal indicator; the dry ice gradually acidifies the solution causing the color to change in the order purple, blue, green, yellow, orange 

 

Electrolysis of Water – Electrolyze water (dilute Na2SO4 solution with indicator) in the Hoffman apparatus to decompose it into its component elements, hydrogen and oxygen. If desired, you can test the H2 (g) and/or O2 (g) produced with a flame and a glowing splint, respectively. 

 

The Tyndall Effect – Demonstrate the Tyndall effect and simulate a sunset on the overhead projector by reacting Na2S2O3 with HCl to produce a colloidal suspension of sulfur. 

 

 

Thank you and have a great week!  

-The Demo Lab  

  

PS if you are ahead/behind of schedule let us know so we can adjust the demos accordingly. Currently we are simply using the syllabi to guess where your respective classes are at.  and here is the link again 🙂: Demo Ordering Link

Suggested Demos for: Feb. 5th-Feb. 9th

 

Hello Professors!

Today is Thursday, February 1st, and these are the hottest and trendiest demonstrations for the upcoming week! 

The chemicals are absolutely flying off the shelves, so order while you can!  

 

Here is the link (Password: hydrogen) to order as well as the full list of demos; as always, early orders are very appreciated! 

 

General Chemistry I:  

  

Weekly topics  

-Reactions in aqueous solutions 

-Thermochemistry 

  

Suggested Demonstrations 

 

Potassium and Water – Drop a piece of potassium into an aquarium containing water and phenolphthalein to produce H2 (g) and KOH (aq) – the heat of reaction ignites the H2 (g) and a lavender flame is observed (from the K+), while the indicator turns pink from the formation of KOH. 

 

Crystallization of Supersaturated Sodium Acetate Solution – Add a tiny crystal of sodium acetate to a 2 L flask of a super-saturated solution to cause the solid to crystallize out, leaving almost no liquid – this demonstration is beautiful and dramatic, as well as being quite exothermic. Alternatively, you can pour the solution slowly over a single crystal to build up a column of solid sodium acetate. 

 

Yamada and Dry Ice – Add a chunk of dry ice to a 2 L cylinder containing a basic solution and Yamada universal indicator; the dry ice gradually acidifies the solution causing the color to change in the order purple, blue, green, yellow, orange. 

 

Hot and Cold Packs – Combine NH4NO3 (s) and water in a Ziploc bag to make an instant “cold pack”. 

 

Thermite – Perform the thermite reaction, in which Al and Fe2O3 react to produce molten iron.
NOTE: 48 hour notice is required for this demonstration 

 

Combustion of Ethanol Vapors – Allow a small amount of ethanol to vaporize in a large carboy, pour out the excess liquid, and hold a lighted splint to the mouth of the container – the impressive reaction also demonstrates the explosive flammability of organic vapors.  

 

Ammonium Dichromate Volcano – Ignite a pile of (NH4)2Cr2O7 volcano in an aquarium to produce N2 (g), H2O (g), and Cr2O3 (s). The resulting reaction looks very much like an erupting volcano. 

 

General Chemistry II:  

  

Weekly topics  

-Acid/base equilibria 

-Precipitation reactions 

  

Suggested Demonstrations  

Le Chatelier’s Principle: Iron (III) Thiocyanate Equilibria – Apply stress to the Fe3+ + SCN- → FeSCN2+ system in five different ways to show the equilibrium shifts accompanying changes in the concentration of reactants.  

Effect of Temperature on NO2 ↔ N2O4 Equilibrium – Immerse sealed tubes of NO2/N2O4 in hot and cold water to show how temperature shifts the equilibrium position and to show the reversibility of the shift; red-brown NO2 predominates at high temperatures and colorless N2O4 at lower temperatures  

Yamada and Dry Ice – Add a chunk of dry ice to a 2 L cylinder containing a basic solution and Yamada universal indicator; the dry ice gradually acidifies the solution causing the color to change in the order purple, blue, green, yellow, orange.  

Acidic and Basic Oxides – Dissolve several oxides (CaO, ZnO, CO2, P4O10) in water containing universal indicator to show a range of basic and acidic oxides. 

 

Amphoteric Hydroxides: Al3+ and Fe3+ – add NaOH to samples of Al(NO3)3 and Fe(NO3)3 to form insoluble metal hydroxides, then add HNO3 and more NaOH to different samples of each to identify which metal hydroxides are amphoteric 

  

General Chemistry for Engineers:  

  

Weekly topics  

-Gases 

-The Periodic Table and Atomic Structure 

  

Suggested Demonstrations (please electrocute the pickle) 

 

Squashing Pop Cans with Atmospheric Pressure – use atmospheric pressure to squash pop cans.  

Boiling Water at Room Temperature – Show water boiling at room temperature in a beaker in an evacuated bell jar, then put your hand in the water after boiling to convince students of its low temperature. (Upon request, we can give you a clean beaker and tap water if you want to drink the boiled water)  

Graham’s Law – Allow concentrated NH3 and concentrated HCl to vaporize and meet in a horizontal glass tube, forming a ring of NH4.  

 

Gas Discharge Tubes of the Noble Gasesshow that different gases give different colors when subjected to an electric discharge (H2 tube also available) 

Fireworks Balloons – Show the brilliant colors of metal cations in a fun way by igniting hydrogen balloons containing metal salts. 

 Pickle Electrocutor – Run an electric current through a dill pickle using a special apparatus to show students that the brine in the pickle conducts electricity, and the current heats and excites the sodium atoms present to a higher energy level. The emission of photons as the sodium returns to the ground state accounts for the yellow color of the light. 

 

Elementary Chemistry:  

  

Weekly topics  

-Organic Compounds 

  

Suggested Demonstrations  

 

Disappearing Styrofoam CupMake a Styrofoam (expanded polystyrene) cup disappear by placing it in a dish of acetone. 

Miscibility and Immiscibility Mix ethanol and colored water in one beaker and hexane and colored water in another to demonstrate miscibility and immiscibility due to differences in the intermolecular forces of alcohols as the size of the alkyl group increases. 

Oxidation of AlcoholsDemonstrate the oxidation of ethanol with K2Cr2O7 on the overhead projector; the alcohol solution changes from orange to green to blue as the Cr(VI) is reduced; this reaction is the basis for the Breathalyzer test. 

  

Thank you and have a great week!  

-The Demo Lab  

  

PS if you are ahead/behind of schedule let us know so we can adjust the demos accordingly. Currently we are simply using the syllabi to guess where your respective classes are at.  and here is the link again 🙂: Demo Ordering Link
 

Hello Professors! 

Today is Monday, January 29th, and these are the hottest and trendiest demonstrations for the upcoming week!

The chemicals are absolutely flying off the shelves, so order while you can!

Here is the link (Password: hydrogen) to order as well as the full list of demos; as always, early orders are very appreciated!

 

General Chemistry I:

 

Weekly topics

-Chemical Reactions and Stoichiometry

-Reactions in aqueous solutions

 

Suggested Demonstrations

Combustion of Ethanol Vapors – Allow a small amount of ethanol to vaporize in a large carboy, pour out the excess liquid, and hold a lighted splint to the mouth of the container – the impressive reaction also demonstrates the explosive flammability of organic vapors.

 

Ammonium Dichromate Volcano – Ignite a pile of (NH4)2Cr2O7 volcano in an aquarium to produce N2 (g), H2O (g), and Cr2O3 (s). The resulting reaction looks very much like an erupting volcano.

 

Potassium and Water – Drop a piece of potassium into an aquarium containing water and phenolphthalein to produce H2 (g) and KOH (aq) – the heat of reaction ignites the H2 (g) and a lavender flame is observed (from the K+), while the indicator turns pink from the formation of KOH.

Crystallization of Supersaturated Sodium Acetate Solution – Add a tiny crystal of sodium acetate to a 2 L flask of a super-saturated solution to cause the solid to crystallize out, leaving almost no liquid – this demonstration is beautiful and dramatic, as well as being quite exothermic. Alternatively, you can pour the solution slowly over a single crystal to build up a column of solid sodium acetate.

Yamada and Dry Ice – Add a chunk of dry ice to a 2 L cylinder containing a basic solution and Yamada universal indicator; the dry ice gradually acidifies the solution causing the color to change in the order purple, blue, green, yellow, orange.

General Chemistry II:

 

Weekly topics

-Chemical equilibria

-Acid/base equilibria

 

Suggested Demonstrations

Le Chatelier’s Principle: Iron (III) Thiocyanate Equilibria – Apply stress to the Fe3+ + SCN- → FeSCN2+ system in five different ways to show the equilibrium shifts accompanying changes in the concentration of reactants.

Effect of Temperature on NO2 ↔ N2O4 Equilibrium – Immerse sealed tubes of NO2/N2O4 in hot and cold water to show how temperature shifts the equilibrium position and to show the reversibility of the shift; red-brown NO2 predominates at high temperatures and colorless N2O4 at lower temperatures

Yamada and Dry Ice – Add a chunk of dry ice to a 2 L cylinder containing a basic solution and Yamada universal indicator; the dry ice gradually acidifies the solution causing the color to change in the order purple, blue, green, yellow, orange.

Acidic and Basic Oxides – Dissolve several oxides (CaO, ZnO, CO2, P4O10) in water containing universal indicator to show a range of basic and acidic oxides.

 

General Chemistry for Engineers:

 

Weekly topics

-Stoichiometry

-Gases

 

Suggested Demonstrations

Squashing Pop Cans with Atmospheric Pressure – use atmospheric pressure to squash pop cans.

Boiling Water at Room Temperature – Show water boiling at room temperature in a beaker in an evacuated bell jar, then put your hand in the water after boiling to convince students of its low temperature. (Upon request, we can give you a clean beaker and tap water if you want to drink the boiled water)

Graham’s Law – Allow concentrated NH3 and concentrated HCl to vaporize and meet in a horizontal glass tube, forming a ring of NH4.

Avogadro’s Law – Three flasks containing equal amounts of acetic acid are fitted with balloons containing different amounts of NaHCO3; mix the reagents by lifting and shaking the balloons: the balloons will inflate with CO2 to a volume proportional to the number of moles produced, in accordance with Avogadro’s law.

H2/O2 Balloon Series – Light a series of balloons containing different ratios of H2 (g) and O2 (g): pure H2, 2:1, 1:1, 1:2, pure O2. The loudest bang occurs when the ratio is stoichiometric, 2:1.

 

 

Elementary Chemistry:

 

Weekly topics

-Compounds- how elements combine

 

Suggested Demonstrations

Gas Discharge Tubes of the Noble Gases– show that different gases give different colors when subjected to an electric discharge (H2 tube also available)

Halogens – Display flasks containing the halogens chlorine, bromine, and iodine.

The VSEPR model – Use 5 sets of balloons to illustrate the VSEPR shapes: linear, trigonal planar, tetrahedral, trigonal bipyramidal, and octahedral.

 

 

Thank you and have a great week!

-The Demo Lab

 

PS if you are ahead/behind of schedule let us know so we can adjust the demos accordingly. Currently we are simply using the syllabi to guess where your respective classes are at.  and here is the link again 🙂: Demo Ordering Link

Welcome to the ThunderDome!

50k+ students, staff, and faculty enter, then leave again because Corona.

The Demo Lab is shut down this semester, and I don’t have any students, but I will be around. Email me directly if you need help with something.

Visit our YouTube channel to see all the demo videos we have available. Pleas subscribe and encourage your students to do the same.

On the Demo Video page we have the videos arranged by class and chapter, and have links to the pdf protocols.

Wear your mask and keep, I dunno, 3 m away from everyone.

 

Angie