3.1

Water Water is essential to life as we know it, but why? Water has some unique properties that make it so special. Water is composed of 2 Hydrogen atoms and 1 Oxygen atom. The Oxygen is bigger and “stronger” than the Hydrogen so it “pulls” the shared electrons closer to itself.

For this reason water is a Polar Compound, this means that the molecule has an uneven charge. The O end is slightly – and the H end is slightly +. This polar nature of water causes water molecules to be attracted to each other. This type of attraction between the + end of one water molecule and the – end of the next is called a Hydrogen bond. Brightstorm Hydrogen Bond [] __Properties of Water __ 1) Cohesion – Attractive __#|force__ between molecules of the same type. This property of water causes surface tension. Surface tension can be broken with detergents. 2) Adhesion – Attractive __#|force__ between molecules of different types. This property of water causes water to “stick” to surfaces. Capillarity – Capillary Action – The tendency of water to “flow” upward against the pull of gravity through small tubes or pores. This is due to Adhesion and Cohesion working together 3) Thermal Regulation – Moderation of Temperature – Slow gain or loss of heat prevents sudden shifts in temperature. 4) Solvent – The polar nature of water allows it to dissolve other polar compounds as well as ionic compounds. Any solution in which water is the solvent is called an aqueous solution. Science Guy [] Properties of Water [] Review of Water  []

Mixture - a combination of two or more substances that are physically combined 1) Solution - a solute is dissolved in a solvent, and will not settle out over time
 * 3 Types of Mixtures**
 * Solute - Substance being dissolved in a solution.
 * Solvent - substance that dissolves the solute.
 * Saturated - Solution that contains all of the solute it can hold.
 * Super Saturated - Solution is "forced" to hold more solute than normal. (Add heat)
 * Concentration - the amount of solute in solvent. ex. (5g/L)

2) Suspension - One substance is suspended in another, will settle out over time

3) Colloid - Exists in two states. Sol (liquid) and Gel (semi-solid)