Hello Professors!!! Today is Friday, March 22^nd 

… 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:

*Midterm Week Good Luck!

General Chemistry II:

Weekly topics

• Chemical Thermodynamics
• Electrochemistry

• d-block elements (Transition metals)

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
• Multiple Oxidation States of Manganese – Starting with KMnO4(aq) in four beakers, carry out reactions to display manganese in the +7, +4, +3, and +2 oxidation states

• Copper/Zinc Voltaic Cell – Demonstrate a copper/zinc voltaic cell turning a motor to show that a spontaneous reaction can be harnessed to do work.
• 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 Kinetics
• Concentration dependence of rates

Suggested Demonstrations 

• Iodine Clock Reaction – Perform the iodine clock reaction with three different initial concentrations of IO3-
• Alka Seltzer at Three Temperatures –Three students add Alka-seltzer tablets to flasks containing water at different temperatures and quickly seal the flasks with stoppers fitted with balloons, which will inflate at different rates
• H2/O2 balloon – Ignite a balloon filled with a stoichiometric mixture of hydrogen and oxygen to show the extremely exothermic reaction to produce water.

Elementary Chemistry:

Weekly topics

• Strong acids/bases
• Weak acids/bases
• Buffers

Suggested Demonstrations

• Acids and Bases – Add drops of 0.1 M NaOH to a magnetically stirred solution of water and universal indicator until it turns blue, then add drops of 0.1 M HCl until the solution turns orange.
• Strong and Weak Acids and Bases – Use two conductivity testers with light bulbs to contrast the conductivity of weak and strong electrolytes: acetic acid and HCl (aq), and/or NH₃ (aq) and NaOH (aq)
• Acid-Base Titration – Add NaOH (aq) to a solution of HCl and phenolphthalein
• 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 Breath – Have a student wearing a white or light-colored shirt use a straw to blow into water containing Yamada universal indicator or to observe the color change accompanying the reaction
• Acidity and Basicity of Salts (Formerly Hydrolysis of Salts) – Dissolve various salts in water containing Yamada indicator to demonstrate their acidity or alkalinity in solution.

Foundations of General Chemistry:

Weekly topics

• Real gas laws
• Pressure
• Effusion/Diffusion
• Stoichiometry

Suggested Demonstrations

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

• 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)
• Vanilla Balloons – Pass around a few balloons containing a potent osmophore (vanilla) and ask students to identify the odor; the odor is detectable because of the diffusion of vanillin molecules through pores in the balloon.
• Charles’ Law – Pour liquid nitrogen over a balloon to show that a decrease in T is accompanied by a decrease in V.

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

 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
• 2^nd and 3^rd 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