Chapter 12 – Solutions Chapter 12-1: Types of Mixtures St. Augustine Preparatory School January 23, 2017

Necessary Terms - Matching Definitions (match to a term) ___ Solution A. capable of being dissolved ___ Solvent B. homogenous mixture of two or more substances in a single phase ___ Soluble C. The dissolving medium in a solution ___ Solute D. The dissolved substance in a solution

Necessary Terms - Matching Definitions (match to a term) B. Solution A. capable of being dissolved C. Solvent B. homogenous mixture of two or more substances in a single phase A. Soluble C. The dissolving medium in a solution D Solute D. The dissolved substance in a solution

Homogeneous and Heterogeneous Mixtures Homogeneous mixtures are uniform throughout the entire sample. You could not separate the components easily. Examples: salt water, orange juice (no pulp), brewed coffee Heterogeneous mixtures do not appear uniform and could be separated relatively simply. Examples: fresh milk with cream on top, chicken noodle soup, orange juice with pulp.

Salt and Iron – Homogeneous or Heterogeneous? Can a mixture of salt and iron be easily separated? If so, how? If not, why not?

Homogeneous or Heterogeneous? Ask yourself: Evenly distributed or not? Easily separated or not?

Types of solutions 1. Gaseous solutions - Example: the air around us (78% Nitrogen, 21% oxygen, 0.9% argon, and trace amounts of other gases) 2. Liquid solutions - Liquid in liquid (alcohol in water) - Solid in liquid (salt in water) 3. Solid solutions - Gold alloy: 14-karat gold is an alloy of gold with silver and copper. It is 14/24 = 58.3% gold.

Suspensions The particles in a solvent are so large that they settle out unless the mixture is constantly stirred or agitated Particles in a suspension are on the order of 1000 nm in diameter Particles in a suspension can be filtered out Particles are visible to the naked eye

Colloids Particles in colloids are smaller than particles in suspensions Particles remain suspended by the movement of surrounding molecules Particles are not easily filtered. Particles not visible to the naked eye.

Tyndall Effect Many colloids appear homogeneous because the individual particles cannot be seen. The Tyndall Effect is noticed when a light is shone through a colloid and the light scatters.

Solutes Electrolytes: A substance that dissolves in water to give a solution that conducts electric current Ionic solutions formed from ionic solids Nonelectrolyte: A substance that dissolves in water to give a solution that does not conduct an electric current. Neutral solute molecules, molecular compounds

Electrolytes When an ionic compound dissolves, the positive and negative ions separate from each other and are surrounded by water molecules. These solute ions are free to move, making it possible for an electric current to pass through the solution.

What Does Dissolving Look Like? https://www.youtube.com/watch?v=xdedxfhcpWo https://www.youtube.com/watch?v=0cPFx0wFuVs Dissolving is different for compounds (ionic) and molecules (molecular/covalent).

Question to Complete Complete questions: 1, 2, 3, 4, 6