Practical 11.1
The reactions of magnesium and calcium with water and air
The reactions of magnesium and calcium with water and air
In this practical:
• you will test the reaction of magnesium and calcium with cold water • your teacher will demonstrate the reaction of magnesium with steam • you will burn magnesium in air • your teacher will burn calcium in air • you will observe and compare the results.
Safety
Wear eye protection at all times.
Take care when heating the magnesium. The light from the flame produced can damage eyes if viewed directly. Similar precautions are necessary when observing the teacher demonstrations.
Apparatus (per student)
• samples of magnesium ribbon (2 cm) and calcium granules • forceps • two 250 cm 3 beakers • tongs • Bunsen burner and heatresistant mat
• spatula • test tube • universal indicator solution • distilled water • eye protection
Procedure
Reactions with water
1 Put 50 cm 3 of distilled water into a beaker. Add a little universal indicator solution to the water before adding a small piece of magnesium or calcium. Observe the different rates and vigour of the reactions of magnesium and calcium with water.
2 Compare the reaction between magnesium and cold water with the reaction between magnesium and steam, which your teacher will demonstrate to you.
3 Record your observations and write balanced symbol equations for the reactions taking place.
Reactions with air
1 Hold 2 cm of magnesium ribbon in the tongs.
2 Hold the metal in the Bunsen flame and make observations about the vigour of the reaction.
3 Using a spatula, collect the product and place it in a test tube.
4 Add water to the product and then a few drops of universal indicator solution.
5 Compare the reaction between magnesium and oxygen with that between calcium and oxygen, which your teacher will demonstrate to you.
6 Record your observations and write balanced symbol equations for the reactions taking place.
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