Solute and Solvent

1. Introduction to Solutions Solute and Solvent

2. Review of Matter • What are the two broad categories of matter? • Mixtures • Pure substances • What are the two types of pure substances? • Element • Compound • What are the two types of mixtures? • Homogeneous • Heterogeneous

3. Homogeneous Mixtures • Also known as solutions • What are the two “s” words that every solution must have? • solute • solvent • Solute = What gets dissolved • Solvent = What does the dissolving

4. A Salt Water Solution Solute (salt) Solvent (water)

5. Types of Solutions • Saturated • Unsaturated • Supersaturated

6. Saturation • Saturated solution • Solvent holds as much solute as is possible at that temperature. • Undissolved solid remains in flask. • Dissolved solute is in equilibrium with solid solute particles.

7. Saturation • Unsaturated Solution • Less than the maximum amount of solute for that temperature is dissolved in the solvent. • No solid remains in flask.

8. Saturation • Supersaturated • Solvent holds more solute than is normally possible at that temperature. • These solutions are unstable • Crystallization can often be stimulated by adding a “seed crystal” or scratching the side of the flask.

9. Determining Saturation Level • You can determine the level of saturation by adding a crystal of solute to a solution. • In a saturated solution, the crystal will remain undissolved (even with stirring). • In an unsaturated solution, the crystal will dissolve. • In a supersaturated solution, the crystal will initiate crystallization.