The structure of atoms: 9.2.3 - Element familiarity
Activity - Student experiment
Hydrogen gas and zinc metal
Place a small strip of zinc into a test tube and add about 10ml of dilute sulfuric acid. Add a few crystals of copper sulfate.
Allow to react with a bung gently resting in the end of the test tube.
Test the hydrogen gas formed by removing the bung and quickly applying a lighted splint
Pour about 20ml of hydrogen peroxide solution (20 vol) into a test tube. Add one small spatula of manganese(IV) oxide.
Test the gas produced by lowering a glowing splint into the test tube (light the splint and then blow it out. Use while still glowing red).
Place a few iodine crystals into a test tube containing 10 ml water. Shake the tube gently.
Place a few iodine crystals into a test tube containing 10 ml propanone. Shake gently
Place a few iodine crystals into a test tube containing 10 ml hexane. Shake gently
Pour about 10ml of dilute hydrochloric acid into a test tube. Add one small spatula of potassium manganate(VII). If necessary, warm gently.
Test the gas produced by holding a piece of damp indicator paper in the mouth of the test tube.
Place the test tube in the fume cupboard in the beaker provided.
Observe the sample of carbon and place a small amount in a dry test tube.
Using a test tube clamp, heat strongly with a Bunsen burner.
The reaction between zinc and sulphur
This will be a demonstration by the teacher. The two elements react directly together producing a new substance. The reaction needs a little energy to get it started
The reaction between aluminium and iodine
This will be a demonstration by the teacher. The two elements react directly together producing a new substance. The reaction is catalysed by water.
2Al + 3I2 --> 2AlI3
Evidence for chemical reaction involves the formation of a new white compound and the release of large amounts of energy.
The reaction between carbon and oxygen
A sample of carbon is placed in a deflagrating spoon and heated very strongly.
At the same time a gas jar is filed with oxygen by adding manganese(IV) oxide catalyst to about 20 ml of hydrogen peroxide solution.
The glowing carbon is then placed (in the deflagrating spoon) into the gas jar of oxygen and the reaction observed.
The carbon continues to glow for some time as it reacts exothermically with the oxygen gas.
C + O2 --> CO2
Student follow up
Classwork and homework
They have investigated eight elements.
The students are to describe the physical and chemical properties that they have encountered. Also their symbols, formula and positions in the periodic table.
The lesson is likely to take at least one double and one single lesson to complete the experimental tasks, rotating around the groups.
The teacher demonstration component takes about 1 single lesson