Three Easy Gases: Carbon Dioxide, Hydrogen, and Oxygen

     Each of these gases makes a good one or two period (45 min) laboratory activity for high school and university students. In General Chemistry lab, we use a 3-hr lab period to make all three gases and do many of the suggested experiments.  These gases are easy to make and all three are made the same way, so once students have successfully made one of the gases (CO2), they know how to make the other two!  However, each gas has its own personality - hydrogen production is very fast and oxygen is slow.  These gases are non-toxic, cost only pennies per syringeful to make and produce no chemical wastes.  Each gas has 5 - 10 suggested experiments that can be done with the gas.

Cost per syringeful (60 mL):

     Carbon dioxide is the gas we start with when we do our Microscale Gas Chemistry Workshops.  We can use baking soda and vinegar (although we usually use 1 molar HCl). 
Cost per syringeful (60 mL):
     Hydrogen is the second gas we make with participants of our Microscale Gas Chemistry Workshops.  Use the same method as for CO2, but with Mg and 2 M HCl.  
Cost per syringeful (60 mL):
     Oxygen is the third gas we make in our Microscale Gas Chemistry Workshops.  Same method as for CO2 and H2, but with 6% H2O2 and KI(s). The reaction is a lot slower. 

Above: Some teachers who are excited about their first syringe gas preps.

Left: Students getting ready to launch a H2 and O2-filled mini-rocket (a plastic pipet bulb.
Right: A similar rocket being launched in the dark (time-lapsed film photography.)

Watching the pH of water drop with universal indicator  as carbon dioxide is bubbled through the sample.  Left: In a small test tube - only 5 mL CO2 is used and the rest can be used for other experiments. Right: As a classroom demonstration, carbon dioxide gas is layered over a solution made slightly basic with ammonia fumes.  The picture is a progression of color changes with time as the carbon dioxide goes into solution and the pH drops.

Website last updated 9 Mar 2010