1. Chemistry Chapter 3 Notes #2

2. Matter Pure Substances (can be represented by a chemical Formula) ElementsCompounds Mixtures (can be separated By physical means) Homogenous Solution Heterogeneous Suspension Colloid

3. Matter- Pure Substances  All samples of matter are composed of atoms… The smallest particles possessing the properties of an element  Fundamental chemical substances from which all other substances are made  When 2 or more types of atoms combine and cannot be separated by physical means = compound! (must be separated by chemical change)

4. Mixtures  To tell them all apart: Colloid and solution V. Suspension  A suspension settles out, making it different from both of the other two. Colloid V. solution  The TYNDALL EFFECT : Shine a beam of light through each. If you can see the light beam traveling thru = colloid (the light bounces off the particles that are suspended). No light beam = solution

5. SolutionSuspensionColloid Appearance Clear, transparent and homogeneous Cloudy, heterogeneous, at least two substances visible Cloudy but fairly uniform Particle Size smallestbiggestMedium (intermediate) Effect of Light Tyndall Effect none -- light passes through, particles do not reflect light variablelight is dispersed by colloidal particles Effect of Sedimentation noneparticles will eventually settle out none

6. Separating Mixtures  Mixtures can be separated by physical means Filtration – porous barrier to separate Chromatography- separates parts of a mixture on the tendency of each part to be drawn across the surface of another material Distillation – differences in boiling points Crystallization – results in the formation of solid particles  Change of state