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Gases
in Your Curriculum
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Dear Gas Enthusiasts,
Early in the first year chemistry course, students learn measurement
skills. Being able to determine the mass of a solid and the volume
of a liquid is essential before any laboratory experiments with
gas chemistry can be done. Understanding concepts of matter is
another important topic that occurs early in the curriculum and
is essential to the study of gases — the three phases and
phase changes, heterogeneous and homogeneous materials, substances,
physical and chemical changes. After students have learned to
measure the mass of an object, know how to read the volume of
a liquid, and have some concept of matter, they are ready to generate
carbon dioxide. In addition to reinforcing measurement skills,
students will add useful laboratory skills and learn how to measure
the volume of a gas. Performing experiments with carbon dioxide
should wait until students have some background in chemical formulas
and reactions.
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After the students
have studied chemical formulas, and chemical reactions, they are
ready to prepare the “3 Easy Gases”, carbon dioxide, hydrogen
and oxygen and study their chemical reactions. Unlike most traditional
experiments involving gases, our experiments focus on the chemical
reactions and chemical properties of gases, rather than the physical
properties and gas laws.
This website (and book) provides four student laboratory experiments
for each of the gases, carbon dioxide, hydrogen and oxygen. Each
gas can be prepared and studied in one or two laboratory periods.
Students can perform these experiments at this point in the curriculum.
The website/book provides a number of demonstrations that can be
presented by the teacher to augment classroom activities. These
usually involve a subtle observation that is best appreciated with
explanation by the teacher, experiments that take longer than one
laboratory period to complete, experiments that require some practice
that is more practical for the teacher than a classroom, or experiments
that use a chemical that should not be handled by typical students.
A list of the laboratory experiments as they appear at this website
(and in our book) and classroom demonstrations for the gases, carbon
dioxide, hydrogen, and oxygen follows.
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Experiments
with Carbon Dioxide
Preparation of Carbon Dioxide
Student Laboratory Experiments with Carbon Dioxide
1. Traditional limewater test for carbon dioxide
2. Acidity of carbon dioxide
3. Carbon dioxide extinguishes fires
4. Carbon dioxide and aqueous sodium hydroxide react
Demonstration or Advanced Experiment with Carbon Dioxide
5. Carbon dioxide/carbonic acid equilibrium
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Experiments
with Hydrogen
Preparation of Hydrogen
Student Laboratory Experiments with Hydrogen
1. Traditional test for hydrogen
2. Hydrogen forms explosive mixtures with air
3. Reversible conversion of copper metal and copper(II) oxide
4. Reduction of iron(III) oxide with hydrogen
Demonstrations and Advanced Experiments with Hydrogen
5. Effusion of hydrogen is faster than air
6. Hydrogen burns with a gentle flame
7. Disappearing/reappearing candle flame
8. Calcium and calcium hydride produce hydrogen in reactions with
water
Experiments with Oxygen
Preparation of oxygen
Student Laboratory Experiments with Oxygen
1. Traditional test for oxygen
2. Oxygen supports combustion
3. Dynamite soap
4. Hydrogen-oxygen rockets
Demonstrations and Advanced Experiments with Oxygen
5. Steel wool burns in oxygen
6. The Blue Bottle experiment
7. Oxygen makes the flame hotter
8. Mini-sponge shooter
9. Chemiluminescence
In our section titled “Lab Experiments”, we provide eight
experiments that can be used as full-laboratory period experiments
that are useful in teaching specific topics in chemistry. Those
marked with * also can be used as classroom demonstrations.
Microscale formation of iron lab*
Microscale reaction between copper(II) oxide and hydrogen*
Mystery Gas
Carbonated Beverages — Priestley’s Soda-water
Molar Mass*
Limiting Reagent
Barometric Pressure without a Barometer
Teacher goals for first year should include: (a) incorporate the
three gases, carbon dioxide, hydrogen and oxygen into the laboratory
curriculum and classroom demonstration repertoire, and (b) implementation
of a few of the laboratory experiments listed above.
During the
second year, teachers should add a few more labs listed above and
try preparing and studying other gases as suits the curriculum.
Excellent (and fun!) experiments are available to teach concepts
such as acid rain, acid rain • air pollution • catalysis
• combustion • environmental issues • equilibrium
• Ideal gas law • intermolecular forces • kinetics
• microexplosions • molar mass • oxidation/reduction
• precipitation • reaction stoichiometry • rocketry
• solubility, • organic chemistry, and much more. However,
many of these concepts require the preparation of other gases than
the “3 Easy Gases”. The “blue button” gases
under “All 17 Gases” would be the most logical next set
of gases to add to your program, depending on personal interest.
My personal favorite gases for classroom demonstrations, not including
the 3 easy gases, are nitrogen dioxide, ammonia and hydrogen chloride.
Enjoy! Have fun!
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