Burningof sulphur – acid rain demonstration (Science & Society connection)
Apparatus: gas bottle, BTB indicator, glass plate, deflagrating spoon & sulphur.
Directions:
1. Fill gas bottle with water and add a few drops of BTB (indicator turns yellow in an acid or remains blue in basic or neutral solutions).
Put ½ tsp (amount is not critical) into the spoon and heat over the Bunsen burner flame. Ask a student to turn off the light so that the violet flame can be viewed.
Lower the spoon into the gas bottle, taking care not to touch the sides (see photograph). Cover with the glass plate. The white gas (SO2 and SO3) will billow and fill the air space above the blue liquid. Douse the flame in a waiting container of water (Safety alert – toxic gas produced is, use a fume hood).
Discuss with the class about societal and environmental implications of factories burning sulphur and the products that will come out of the smokestacks, like sulphur dioxide and trioxide. During this time, these two gases will dissolve into the water to form sulphurous and sulphuric acid, changing the pH from neutral to acid.
Cover the top of the bottle completely with the glass plate and shake once. The blue coloured solution will dramatically change to yellow. This indicates that the solution is now an acid. Explain how this demonstration shows how we get acid rain and the effects of air pollution on our lakes.
Extension: In Southern Ontario, there is a buffering effect of limestone (CaO) that will react with water to form calcium hyroxide (CaO + H2O--> Ca(OH)2). Since metal hydroxides are bases, this counteracts the effect of the acid rain. Therefore, Southern Ontario is not as affected by acid rain as it could be.
Apparatus: gas bottle, BTB indicator, glass plate, deflagrating spoon & sulphur.
Directions:
1. Fill gas bottle with water and add a few drops of BTB (indicator turns yellow in an acid or remains blue in basic or neutral solutions).
Put ½ tsp (amount is not critical) into the spoon and heat over the Bunsen burner flame. Ask a student to turn off the light so that the violet flame can be viewed.
Lower the spoon into the gas bottle, taking care not to touch the sides (see photograph). Cover with the glass plate. The white gas (SO2 and SO3) will billow and fill the air space above the blue liquid. Douse the flame in a waiting container of water (Safety alert – toxic gas produced is, use a fume hood).
Discuss with the class about societal and environmental implications of factories burning sulphur and the products that will come out of the smokestacks, like sulphur dioxide and trioxide. During this time, these two gases will dissolve into the water to form sulphurous and sulphuric acid, changing the pH from neutral to acid.
Cover the top of the bottle completely with the glass plate and shake once. The blue coloured solution will dramatically change to yellow. This indicates that the solution is now an acid. Explain how this demonstration shows how we get acid rain and the effects of air pollution on our lakes.
Extension: In Southern Ontario, there is a buffering effect of limestone (CaO) that will react with water to form calcium hyroxide (CaO + H2O--> Ca(OH)2). Since metal hydroxides are bases, this counteracts the effect of the acid rain. Therefore, Southern Ontario is not as affected by acid rain as it could be.
1 comment:
Good and detailed explanation with visually sound.
Request :
Kindly insert the photos or images for the each sequence based on availability.
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