Chemistry Comes Alive! C C Alive! Table of Contents Index Textbooks

Volume 2

Demonstration Notes

These demonstrations are not meant as tools to teach chemical demonstration techniques. They are meant as a tools for classroom use. Many of the demonstrations present safety hazards or are difficult for an entire class to observe as live demos. If you wish to perform the demonstrations shown here, you should obtain a copy of Shakhashiri's Chemical Demonstrations Vol. 1-4 (1); Gilbert, Alyea, Dutton and Dreisbach's Tested Demonstrations in Chemistry, Vol. I and II (2); Ellis, Geselbracht, Johnson, Lisensky, and Robinson's Teaching General Chemistry: A Materials Science Companion (3); Summerlin and Ealy's Chemical Demonstrations, Vol. 1 (5); and Summerlin, Borgford, and Ealy's Chemical Demonstrations, Vol. 2. (6)

Safety information can be obtained from (4).

Credits for the following text: (142 )

Ammonia Fountain

poison irritant gas

Only a round bottom flask should be used in this demonstration, since a flat bottom flask might implode when the vacuum is created during the demonstration. Ammonia gas is a poison that causes severe irritation or burns to the respiratory system. Phenolphthalein is toxic and should not be ingested.

Ammonia Fountains - Multiple

poisonous irritant gas, toxic chemicals

Only round bottom flasks should be used since flat bottom flasks might implode under reduced pressure. Ammonia gas is poisonous and severely irritating to the respiratory system. Ammonia gas may cause chemical burns to the respiratory system. Acid-base indicators may be toxic.

Big Barometer

poison, poisonous vapors

Potassium mercury iodide and mercury are poisonous. The mercury vapors from open containers of mercury are above the maximum safe exposure limit. Mercury spills should be cleaned up promptly with approved mercury spill cleaning methods.

Boiling by Cooling

burns, implosion

Exercise precaution in handling boiling water. Boiling water produces scalding steam. Pressure in the system will decrease with decreasing temperature and the partially evacuated flask should be separated from the audience by an explosion shield. It would be safer to use a round-bottom flask, heated by a heating mantle.

Boyle's Law: J-tube

poison, poisonous vapors

Mercury is poisonous. The mercury vapors from open containers of mercury are above the maximum safe exposure limit. Mercury spills should be cleaned up promptly with approved mercury spill cleaning methods.

Canned Heat

burns, flammable

The product burns with an almost invisible flame. Ethanol is flammable.

Colors of Elements in a Flame

burns, chemical irritation

Use caution with the burner. Use standard chemical safety procedures with the solutions.

Conductimetric Titration

toxic, chemical burns

Barium compounds are toxic. Strong acid and strong base solutions are corrosive and caustic. They should be washed off the skin with water if they are touched. Take care in the handling of the reagents.

Critical Point of Benzene

burns, explosion, toxic chemical, carcinogen

Benzene is toxic and carcinogenic. Working with a hot oil bath in excess of 300oC is obviously dangerous. Benzene in the sealed tube will exert an extremely high pressure near the critical point. Have an explosion shield in place the first time the tube is heated to make certain it can hold the pressure.

Crystallization of Supersaturated Sodium Acetate

If this demonstation is attempted in the classroom, be sure to have more than one sample of supersaturated sodium acetate made up. The slightest bump, or addition of dust or other impurity, may cause the solution to crystallize prematurely.

Curie Point of Nickel

burns, toxicity

Use care in handling the hot metal sphere. Nickel metal can be harmful if swallowed or inhaled and is a possible cancer hazard, based on animal data.

Extraction of Acid with Base

flammable, corrosive chemicals, toxic chemicals, poisonous

Diethyl ether is extremely flammable and diethyl ether vapors are poisonous. Sodium hydroxide and hydrochloric acid are corrosive. If spilled on the skin, they should be washed from the skin with water.

Ferrimagnetism

Use normal laboratory precautions.

Ferrofluid

Care should be taken not to spill the ferrofluid; it is very difficult to clean up.

Floating Squares

flammable, poisonous, carcinogenic

Hexane is flammable. Carbon tetrachloride liquid and vapor are poisonous and carcinogenic.

Hardness of Solid Substances

reactive metal, chemical irritants

The silicon disc produces sharp shards when broken and should be handled with gloves. Lithium is a dangerous, reactive metal. Sulfur, selenium and iodine are potentially irritating.

Hardness of Solid Substances - Grinding

chemical irritants, toxicity

Sulfur, selenium, and iodine are potentially irritating. Lead is poisonous.

Heat Conduction by Diamond

Use normal laboratory precautions.

Heat Treatment of a Metal Bobby Pin

burns

Care must be taken when working with a hot flame. The bobby pin should be handled with forceps during the heating process.

Ice Bomb

explosion, frostbite

The acetone used to cool the ice bomb is flammable. The dry ice/acetone slush should not be placed in a glass container, since the exploding bomb could shatter the glass. It is important that the wooden box be placed over the ice bomb to absorb some of the shock and prevent bomb fragments from flying too far. An explosion shield is also necessary. The bomb fragments are initially very cold and should not be handled. Do not go near the bomb if it does not explode within a short time. Allow it to warm up to room temperature before uncovering an unexploded ice bomb.

Induction by Iron(II) of the Oxidation of Iodide by Dichromate

carcinogenic, corrosive solutions

Chromium(VI) compounds are carcinogenic. The solutions in this demonstration are very acidic and strong acids are corrosive. Wash off with water any spilled on the skin.

Isotopes: Heavy Water Ice Cubes

expensive

Deuterium oxide is expensive and should not be wasted.

Like Dissolves Like - Demonstration

flammable, poisonous, carcinogenic

Hexane is flammable. Carbon tetrachloride liquid and vapor are poisonous and carcinogenic. Gloves should be worn when performing this demonstration. (Erratum: The video can be faulted for showing the pouring of carbon tetrachloride without gloves, an error noticed at the very end of the production process.)

Like Dissolves Like - Multimedia Experiments

flammable, poisonous, carcinogenic

Hexane is flammable. Carbon tetrachloride liquid and vapor are poisonous and carcinogenic.

Liquefaction of Carbon Dioxide

frostbite, explosion

To avoid frostbite, dry ice should not be handled for more than a second or so without gloves. The confined carbon dioxide gas is at great pressure and presents an explosion hazard.

Memory Metal

Care should be taken not to burn fingers when immersing the metal in the hot water bath. Special care must be taken to prevent burns when heating the metal to 500oC to "teach" it a shape.

Mercury Barometers

poison, poisonous vapors

Mercury is poisonous. The mercury vapors from open containers of mercury are above the maximum safe exposure limit. Mercury spills should be cleaned up promptly with approved mercury spill cleaning methods.

Osmotic Pressure, Hydrostatic Pressure

Use normal laboratory precautions.

Paramagnetism: Compounds

carcinogenic

Nickel(II) sulfate hexahydrate is a suspect carcinogen and is harmful if swallowed, inhaled, or absorbed through the skin. Zinc(II) sulfate heptahydrate is harmful if swallowed.

Paramagnetism: Nitrogen and Oxygen

frostbite, combustion

Avoid skin contact with liquid oxygen or liquid nitrogen, since both can cause severe frostbite. Combustion rates in the presence of liquid oxygen are extremely high due to the high O2 concentration.

Paramagnetism: Oxidation States of Manganese

chemical irritants

In preparing the sealed tubes, care needs to be taken in handling the chemicals.

Piezoelectric Effect

Use normal laboratory precautions.

Plastic Sulfur

burns, toxic, irritant gas

Because sulfur dioxide is produced when sulfur is burned, this demonstration should be carried out in a hood. Sulfur dioxide is toxic and a strong irritant with a powerful choking odor. The plastic sulfur may contain molten sulfur at first and is quite hot. It should be handled with caution.

Relative Reactivity of Alkali Metals

explosions, flammable, exothermic

Alkali metals react violently with water. The hydrogen gas that is produced bursts into flame because of the reaction heat. The resulting solutions are strongly alkaline. Exposure of skin to these metals or the reaction products should be avoided.

Ring Strain

flammable, explosive, chemical irritant

Cyclohexene and -pinene are flammable. The reaction of -pinene and iodine is very exothermic, producing dense iodine vapors, which can irritate the respiratory tract.

Simulation of Dislocations in Metals

Use normal laboratory precautions. Be careful with the sharp needle.

Sodium Chloride Crystal Cleavage

It is difficult to grow a crystal suitable for this demonstration. Because the crystal is so small, it is difficult for a large group of students to see the demonstration if performed live.

Superconductivity

frostbite

Avoid skin contact with liquid nitrogen, because it can cause frostbite.

Thermochromism: Mercury(II) Iodide

toxic, burns

Mercury compounds are toxic. Be careful in removing the hot HgI2 from the hot plate.

Vapor Pressure: Collapsing Balloon

burns, scalding steam

Use caution with the hot plate and boiling water that creates scalding steam.

Vapor Pressure: Drinking Bird

burns, fragile

Use caution with the heat lamp. The bird is fragile and easily broken.

Vapor Pressure: H-bonding vs. dipole-dipole attraction

poison, poisonous vapors, equipment breakage and chemical spills, flammable

Mercury is poisonous. The mercury vapors from open containers of mercury are above the maximum safe exposure limit. Mercury spills should be cleaned up promptly with approved mercury spill cleaning methods. Sudden changes in pressure as substances are injected into the barometer can cause breakage hazards. Diethyl ether is extremely flammable and diethyl ether vapors are poisonous. Butanol is flammable and moderately toxic.

Vapor Pressure: Molecular Polarity

poison, poisonous vapors, equipment breakage and chemical spills, flammable, carcinogenic

Mercury is poisonous. The mercury vapors from open containers of mercury are above the maximum safe exposure limit. Mercury spills should be cleaned up promptly with approved mercury spill cleaning methods. Sudden changes in pressure as substances are injected into the barometer can cause breakage hazards. Chloromethane and dichloromethane are flammable, harmful if swallowed, inhaled, or absorbed through the skin, and may be carcinogenic.

Vapor Pressure: Molecular Size

poison, poisonous vapors, equipment breakage and chemical spills, flammable

Mercury is poisonous. The mercury vapors from open containers of mercury are above the maximum safe exposure limit. Mercury spills should be cleaned up promptly with approved mercury spill cleaning methods. Sudden changes in pressure as substances are injected into the barometer can cause breakage hazards. Methanol, ethanol, pentane, hexane, and heptane are all very flammable. Methanol is poisonous if swallowed and can cause blindness. Ethanol is poisonous. Pentane, hexane, and heptane are skin irritants and are hazardous if ingested or inhaled.

Vapor Pressure of a Mixture: Raoult's Law

poison, poisonous vapors, equipment breakage and chemical spills, flammable

Mercury is poisonous. The mercury vapors from open containers of mercury are above the maximum safe exposure limit. Mercury spills should be cleaned up promptly with approved mercury spill cleaning methods. Sudden changes in pressure as substances are injected into the barometer can cause breakage hazards. Diethyl ether is extremely flammable and diethyl ether vapors are poisonous. Decane is flammable. It is harmful if ingested or inhaled and is readily absorbed through skin.

Vapor Pressure: Using Barometers

poison, poisonous vapors, equipment breakage and chemical spills, flammable

Mercury is poisonous. The mercury vapors from open containers of mercury are above the maximum safe exposure limit. Mercury spills should be cleaned up promptly with approved mercury spill cleaning methods. Sudden changes in pressure as substances are injected into the barometer can cause breakage hazards. Ethanol is flammable.

Viscosity of Liquids

volatile, flammable, toxic

Rubbing alcohol and ethylene glycol are flammable and toxic. Ethylene glycol causes central nervous system depression, cardiopulmonary failure, and kidney failure.


Citations

1. Shakhashiri. B. Z. Chemical Demonstrations; University of Wisconsin press: Madison, 1983; Vol. 1.
Shakhashiri. B. Z., Chemical Demonstrations; University of Wisconsin press: Madison, 1985; Vol. 2.
Shakhashiri. B. Z., Chemical Demonstrations; University of Wisconsin press: Madison, 1989; Vol. 3.
Shakhashiri. B. Z., Chemical Demonstrations; University of Wisconsin press: Madison, 1992; Vol. 4.

2. Gilbert, G. L.; Alyea, H. N.; Dutton, F. B.; Dreisbach, D. Tested Demonstrations in Chemistry; Denison University and Journal of Chemical Education: Granville, OH, 1994.

3. Ellis, A. B.; Geselbracht, M. J.; Johnson, B. J.; Lisensky, G. C.; Robinson, W. R. Teaching General Chemistry: A Materials Science Companion, American Chemical Society, Washington, DC, 1993.

4. University of Wisconsin System Administration OSLP EHS MSDS Database; http://www.uwsa.edu/oslp/ehs/msds98-1/ Try this link if you are connected to the web.

5. Summerlin, L. R.; Ealy, J. I., Jr. Chemical Demonstrations, Vol. 1, 2nd Ed., American Chemical Society, Washington, DC, 1988.

6. Summerlin, L. R.; Borgford, C. L.; Ealy, J. B. Chemical Demonstrations, Vol. 2, American Chemical Society, Washington, DC, 1987.


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