MYP 6 Science - Chemistry

MYP 6.2.4: The dissolved state

The dissolved state, an intimate mixture of solute and solvent

Objectives:

  • To understand the words dissolve, solute, solvent, solution.
  • To know that water is a very good solvent.
  • To understand the difficulty of obtaining water in a pure state.
  • To understand that the process of dissolution involves the solvent forming bonds with the particles of the solute.

Introduction

Not all colourless liquids are water! Look at samples of cyclohexane and water and see what happens when they are mixed together.

Teacher demonstration

Compare the solubility (observation) of common salt, iodine, sugar and sulphur in water and cyclohexane.

Class points for discussion

Why do some combinations make solutions while others don't in terms of the forces between the particles?

How can the solute be recovered from the solution by evaporation. What happens to the solvent in this process?

How could the process of evaporation be speeded up?

Is evaporation the same as boiling?

Student activity

Separating salt and sand (Spotlight Science 7: p106)


Resource

Science Explorer - Chemical Interactions Section 2 - Concentration and solubility pp92-97

Spotlight Science 7: p103-111

Video

A nice demonstration - polystyrene cup in propanone


 
previous page
next page
Copyright: 2013 Isis Publication