Classification of Matter

A substance is either an element or a compound.

Element - a pure substance. All of its atoms are the exact same. Found on the periodic table of elements Ex – oxygen, gold

Compound – a substance with 2 or more elements combined in a fixed proportion. Ex – Water always has 2 molecules of hydrogen and 1 molecule of oxygen

A mixture contains 2 or more substances that can be physically separated. Ex – saltwater, dirty water, rocks

4 Types of Mixtures: 1. Homogeneous mixture – a mixture of different materials that looks the same all the way through. No “chunks” Ex - Apple juice, salt water

Homogeneous mixtures are also called solutions. To make a solution, a solute is dissolved in a solvent. In saltwater, the salt is the solute and the water is the solvent. A solute dissolves faster when stirred (creates friction) or heated.

2. Heterogeneous mixture – A mixture of different materials that does NOT look the same all the way through. Has chunks in it Ex – vegetable soup

Colloid – a heterogeneous mixture with particles that never settle ex – smoke

Tyndall Effect – when light hits the particles in a colloid and scatters. You see the Tyndall effect when light comes in through a window and you see the rays.

b. Suspension – a heterogeneous mixture containing liquid that settles into parts ex – Italian Salad dressing