This experiment is for advanced students.

This time we’re going to use a lot of equipment… really break out all the chemistry stuff. We’ll need all this stuff to generate oxygen with potassium permanganate (KMNO₄). We will work with this toxic chemical and we will be careful…won’t we?

[am4show have=’p8;p9;p11;p38;p92;p52;’ guest_error=’Guest error message’ user_error=’User error message’ ]

Oxygen is pretty important… it’s only the single most important thing that mammals need. Besides breathing, oxygen is important for so much on this world. Oxygen is used in welding, rocket fuel, and water treatment. Without oxygen, there is no oxidation and no fire. Simply put, we wouldn’t have rusty bicycles or campfires. Can your believe it?

Potassium permanganate is an important chemical in the film industry. It is used to make props like cloth, ropes, and glass, appear “old”. Some films it has been used in are “Troy”, “Indiana Jones”, and “300”. The KMnO₄ stains any organic material. KMnO₄ is also used as an antiseptic, and is used to treat skin ulcers and rashes. It is also used to treat foot fungus…..phew! People living in the country are sometimes plagued with an iron taste or a rotten egg smell in the water from their wells. Potassium permanganate can be used to remove the taste and smell from the water.

Materials:

• Chemistry stand
• Plastic tub
• Water
• 2 test tubes
• Test tube clamp
• Potassium permanganate (KMnO₄) (MSDS)
• Alcohol burner
• Lighter
• One-hole rubber stopper
• Solid rubber stopper
• 90⁰ bend glass tube
• Measuring spoon
• Rubber tubing
• Match
• Wooden splint

Be careful inserting the glass tubing into the stopper. Wet the short end of the glass tube with water and gently push and twist the glass through the stopper. Wear work gloves and work carefully and slowly. Do not use oil or grease you have laying around the house.

When lighting the oxygen in the test tube, use a wooden splint. Wooden splints can be purchased from craft stores, or make your own by shaving thin strips from a piece of pine wood.

C3000: Experiment

Download Student Worksheet & Exercises

Here’s what’s going on in this experiment:

2KMnO₄ + heat –> K₂MnO₄ + MnO₂ + O₂

Potassium permanganate is heated and produces potassium manganate, manganese dioxide, and oxygen

Oxygen is generated by heating the KMnO₄, and is collected in the test tubes. We will test the contents of the tubes to see if oxygen has been generated. What do you think will happen when a glowing splint is pushed up inside the test tube? Don’t know? Do the experiment and try to figure it out. Remember, in order for there to be flame, you need fuel and oxygen. If that gas was carbon dioxide, what would happen when the glowing splint was placed inside?

Cleanup: Clean everything thoroughly after you are finished with the lab. After cleaning with soap and water, rinse thoroughly. Chemists use the rule of “three” in cleaning glassware and tools. After washing, chemists rinse out all visible soap and then rinse three times more.

Storage: Place all chemicals, cleaned tools, and glassware in their respective storage places.

Disposal: Dispose of all solid waste in the garbage. Liquids can be washed down the drain with running water. Let the water run awhile to ensure that they have been diluted and sent downstream.

[/am4show]