Aim:
To produce and test for hydrogen gas.
Materials:
* rubber stopper * dilute hydrochloric acid (HCI) * zinc pieces (Zn) * test-tube rack * matches * dilute sulphuric acid (H2SO4) * 2 cm strips of magnesium ribbon (Mg) * Iron pieces (Fe) * Test-tube
Method
1. Test the different metals with the acids by separately combining each piece of metal with 5mL of acid in a test-tube. 2. Cover the opening of the test-tube with the rubber stopper to trap any gas. 3. When you think a reasonable amount of gas has built up, light the match, remove the stopper and immediately place the match into the mouth of the test-tube. 4. Record your observations.
Discussion
1. What did the hydrogen gas look like?
The hydrogen gas was colourless. 2. How could you tell when a chemical reaction was taking place?
The gas made a popping sound and the flame flickered. 3. Why did the match need to be placed into the mouth of the test-tube as soon as the rubber stopper was removed?
If the match was placed any later then the gas would have had too much time to escape and would have been incorrectly measured. 4. Write a word equation for the chemical reactions that took place.
Hydrochloric Acid (Hydrogen Chloride) + Magnesium = Magnesium Chloride + Hydrogen
Hydrochloric Acid (Hydrogen Chloride) + Zinc Chloride + Hydrogen
Hydrochloric Acid (Hydrogen Chloride) + Iron = Iron Chloride + Hydrogen Sulphuric Acid (Hydrogen Sulphate) + Magnesium = Magnesium Sulphate + Hydrogen
Sulphuric Acid (Hydrogen Sulphate) + Zinc = Zinc Sulphate + Hydrogen
Sulphuric Acid (Hydrogen Sulphate) + Iron = Iron Sulphate + Hydrogen 5. Are all the metals equally reactive? Can you arrange the ones you tested in order from most reactive to least reactive?
The metals in order from most reactive to least