This experiment is for advanced students.
Zinc (Zn), is a metal and it is found as element #30 on the periodic table. We need a little zinc to keep our bodies balanced, but too much is very dangerous.
Zinc is just like the common, everyday substance that we all know as di-hydrogen monoxide (which is the chemical name for water). We need water to survive, but too much will kill us.
DHMO: In chemistry, “Di” equals the number 2; hydrogen is H; mono equals the number one; and oxide is derived from oxygen, and its symbol is O. Put these together and you have Di-hydrogen (H2), and mono oxygen (O). Put them together, what do you have? Water!
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Materials:
- Goggles
- Gloves
- Test tube rack
- 3 test tubes
- Burner
- Lighter
- Zinc powder (Zn) (MSDS)
- Calcium hydroxide (Ca(OH)2 (MSDS)
- Rubber tubing
- Measuring spoon
- Solid rubber stopper
- Pan
- Water
- Chemistry stand
- Test tube holder
- 90o glass tubing
- One-hole rubber stopper
- Evaporating dish
- Dish soap
- Wood splint
- Measuring syringe
Be careful of the hot test tubes! It may not look hot, but don’t find out the hard way. If a chemist wants to know if something is hot, he places the back of his hand near the surface. If he feels heat, he concludes that it is hot. That’s the same way we test a person’s forehead for a fever. The back of your hand is more sensitive than the front.
Zinc, zinc oxide, and calcium hydroxide are dangerous chemicals. Use your safety equipment. Dispose of the residue in the test tube in the outside garbage.
We will be creating hydrogen gas by making a heterogeneous mixture of zinc powder and calcium hydroxide and heat it. The hydrogen bubbles into test tube in a water bath. When we mix our test tube of hydrogen with the air the room, the hydrogen burns…it actually explodes. Our amounts are small, but you will witness a cool, small, explosion.
In the second part of the lab we will again create hydrogen. This time, we have a tricky way to add oxygen to the hydrogen and we are able to create a ration of 2 parts hydrogen to 1 part oxygen. This is the perfect ratio to make the most explosive mixture of hydrogen and oxygen. The explosion here is very cool.
C3000: Experiment
Download Student Worksheet & Exercises
Here’s what’s going on in this experiment:
In the first part of the lab we produce hydrogen by combining two dry chemicals and heating them. Now two things will happen. Calcium hydroxide, when heated, produces water.
Ca(OH)2 –> CaO + H2O
Calcium hydroxide, when heated, produces calcium oxide and water. This is an oxidation reaction because the calcium oxidizes….combines with the oxygen and releases the other elements.
Next, Zinc will react with water created by calcium hydroxide. As the Ca(OH)2 is heated and turns to water and calcium oxide, the zinc then reacts and produces zinc oxide and hydrogen gas.
Zn + H2O –> ZnO + H2
Zinc when heated in the presence of water, produces zinc oxide and hydrogen gas. This is a single replacement reaction as oxygen kicks out hydrogen and replaces it with zinc.
Here’s the safety information for the products of the reaction:
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. Dry all equipment.
Storage: Place all chemicals, cleaned tools, and glassware in their respective storage places.
Disposal: Dispose of all solid waste in the outside garbage. Liquids can be washed down the drain.
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