Chimica per il liceo/La materia/CLIL
Attività CLIL (metodo IBSE)[modifica]
- Breakfast cereal containing added iron
- Strong magnet
- Projector (if available)
- Strong magnet
- Mass balance
- Weigh boats
- Test tube
- Bunsen burner
- Pestle and mortar
- Iron filings
- 1.0M HCl
Learning aims (Obiettivi):[modifica]
- Observe mixture and compund
- Understand the difference between mixture and compound
What do cereal contain? Teacher shows a video or crush the cereal with the back of a spoon, pestle or other firm kitchen utensil. Keep crushing it until it becomes a fine powder (the finer you can get it, the easier it will be to separate out the iron particles). When teacher has mixed cereal with a powerful magnet, some grey particles are attracted to magnet. https://www.scientificamerican.com/article/get-the-iron-out-of-your-breakfast-cereal-bring-science-home/#:~:text=Crush%20the%20cereal%20with%20the,separate%20out%20the%20iron%20particles
Domanda investigabile: -How does our body digest this iron?
-Do you think this iron will travel through the intestinal tract as an iron nail would?
Add 10 ml of 1.0M HCl to 100 ml of the cereal slurry to simulate stomach acid. Heat in a beaker of hot water.
» After the addition of HCl, the acid oxidises the elemental iron to iron(III) ions, which are not as attracted to a magnet. The addition of NaSCN (sodium thiocyanate) solution should turn the slurry red, thus confirming the presence of these iron ions.
Then Students have to prepare their own mixture and compound samples using the materials and equipment provided.
On completing the investigation, the students should be able to determine the different properties of a mixture and a compound:
» Mixture of iron and sulphur. The iron can still be separated with a magnet (the element retains its property).
» Compound of iron and sulphur. The mixture is heated to form iron sulphide. The iron can no longer be separated by a magnet (the compound has new properties).
Explain the difference between mixture and compound.
Real-life application: Iron is an essential mineral. It is found in haemoglobin in red blood cells. It is needed for the transportation of oxygen from the lungs around the body. If the body does not have enough iron, it cannot make enough oxygen-carrying red blood cells. This deficiency is called anaemia. Healthy red blood cells and sufficient oxygen
is important to prevent fatigue. Athletes need sufficient oxygen supply in their blood and muscles to maximise their performance and prevent fatigue. Blood doping is a method of increasing the number of red blood cells in the body. This allows more oxygen to be carried to the muscles.
And more ... Carry out an investigation on the iron levels in different cereals and compare the results with the levels shown on the cereal packet labels.
Write a report and make an individual quiz as summative assessment