2.2 Properties of Water

Water H 2 O, H-O-H H 2 O, H-O-H Polarity – one region of molecule is more + and other end is more - ; overall neutral Polarity – one region of molecule is more + and other end is more - ; overall neutral - Allows water to be an effective solvent - Allows water to be an effective solvent - It dissolves other polar substances, but won’t dissolve nonpolars - It dissolves other polar substances, but won’t dissolve nonpolars

Hydrogen bonds – weak Hydrogen bonds – weak - Bonds that hold water molecules together - Bonds that hold water molecules together - + attracted to – - + attracted to –

Cohesion – - Attraction between molecules of the same substance Adhesion – - attraction between molecules of different substances

Heat capacity Heat capacity - The amount of heat energy needed to raise temperature - The amount of heat energy needed to raise temperature - High for water - High for water

Mixtures Mixtures – Mixtures – - Made of 2 or more elements or compounds that are physically mixed but not chemically combined - Made of 2 or more elements or compounds that are physically mixed but not chemically combined - Ex. Solutions and suspensions - Ex. Solutions and suspensions

Solution – Solution – - All parts are evenly dispersed - All parts are evenly dispersed - Made of: - solute (substance being dissolved) - Made of: - solute (substance being dissolved) - solvent (substance where solute dissolves) Suspension – Suspension – - Mixture of water and nondissolved material - Mixture of water and nondissolved material

Acids, Bases, & pH Acid – - Substance with more H + than OH - - Substance with more H + than OH - Base – - Substance with more OH - than H +

pH scale – range 0-14 pH scale – range = acid (red) 0-6 = acid (red) 7 = neutral 7 = neutral 8-14 = base (blue) 8-14 = base (blue)

Buffers – Buffers – - Substances that help neutralize strong acids and bases