Gases in Your Curriculum

Student skills needed to get started. 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.

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 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 also 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.

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

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.
Some classroom demos

Carbon dioxide is a weak acid and slowly converts blue Universal indicator starting at pH 8 to a mildly acidic solution (yellow).

Oxygen generated in a syringe and transferred to a large test tube.  Steel wool, held with a metal hemostat is ignited with a 9-v battery and plunged into the oxygen

Document camera or overhead projector demo: Nitrogen dioxide is injected to a sealed food storage bag containing a well plate filled with water as models of lakes.  Some of the lakes are buffered.

Oxygen is added to colorless nitrogen monoxide (formerly in top syringe) to give the instantaneous formation of reddish nitrogen dioxide.

Hydrogen/oxygen rocket (plastic pipet bulb) launched in the dark

Chemiluminescence with oxygen

Gas chemistry experiments are available to teach concepts such as 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.

Enjoy! Have fun!

Last modified 9 Mar 2010