We live in the age of infographics. My students love them and so do I because if well designed they have the power to simplify a complicated subject, plus they can make learning captivating.
My favorite Chemistry infographics are from Compound Interest. They provide excellent examples of mentor texts if students are going to create their own.
Communication is one of the IB’s approaches to learning and creating an infographic is a good way to assess communication skills. Modelling diagrammatically the dissolving process seemed like a good entry point to me and so I thought I could have the students create their own infographic as a formative assessment for Topic 4.4 Solubility. To be able to communicate their ideas they also need to have a good understanding of the physical factors that affect the solubility of different substances and be able to apply this when creating the infographic.
Topic 4.4 Solubility
Essential idea: The physical properties of substances result from the intramolecular and intermolecular forces between their atoms, ions and molecules.
TOK connection: A model can be thought of as a simplified representation of the real world.
Understandings: Students should know that
- Intermolecular forces are found between molecules and include London (dispersion forces), dipole-dipole forces and hydrogen bonding.
- The relative strength of these interactions are London dispersion forces < dipole-dipole forces < hydrogen bonds.
- Intramolecular forces are found between the atoms and ions in a compound. The three types of intermolecular forces are covalent bonds, ionic bonds and metallic bonds.
Applications: Students should be able to
- Deduce the types of intermolecular forces present in covalent molecules, based on their structures and chemical formula.
- Explain the reason for the differences in the solubility of covalent molecules in terms of their structure and intermolecular forces.
Create an infographic a visual representation of the information using labeled diagrams to model solubility at a molecular level. Choose one example from model 1 and 2 and one from model 3 and 4.
Model 1 – Potassium chloride is soluble in water.
Model 2 – Calcium oxide CaO is insoluble in water.
Model 3 – Carbon tetrachloride, CCl4, is insoluble in water.
Model 4 – Methanol, CH3OH is soluble in water.
- For simple covalent molecules, showing two molecules is sufficient. For giant structures, show sufficient atoms to clearly represent the repeating structure.
- Label the intramolecular and strongest intermolecular forces.
- Be neat and visually appealing in a way that helps interpretation.
- Be chemically accurate and have sufficient details (shape, bond angles, relative sizes of ions)
- Support your model with a clear but brief account of the reasons why the solute is soluble / insoluble in the solvent.
Evaluation using a TOK lens
A model can be thought of as a simplified representation of the real world. To what extent do the diagrammatic models you have drawn help or hinder your understanding of solubility?