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Bonds. Ionic Covalent Hydrogen. Bonds. Ionic. Covalent. Share electrons Weaker than ionic 2 types Polar Nonpolar. Transfer electrons Form between ions (+/-). Polar Bonds. Unequal distribution of charge Water molecule. Nonpolar. Equal sharing of electrons. Hydrogen bonds.
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Bonds • Ionic • Covalent • Hydrogen
Bonds Ionic Covalent Share electrons Weaker than ionic 2 types Polar Nonpolar • Transfer electrons • Form between ions (+/-)
Polar Bonds • Unequal distribution of charge • Water molecule
Nonpolar • Equal sharing of electrons
Hydrogen bonds • Attraction between positive hydrogen portion of one molecule… • And negative portion of a second molecule • Water molecules are bonded by hydrogen bonds
Properties of Water • Cohesion • Attractive force • Holds together • Due to H-bonding • ex: water sticking to other water molecules-meniscus
Properties of Water • Surface tension • Related to cohesion • Due to H-bonds • Cause water to be pulled down into liquid • “skin” on top of the water • Water striders • http://www.youtube.com/watch?v=KSLUwmJOo_M
Properties of Water • Adhesion • Attractive force between two different surfaces • Ex: Water molecules and glass molecules
Properties of Water • Capillary action • Raising of liquid • Glass tube, water will rise automatically
Acids: Taste sour Contains H+, (the more H+, the stronger the acid) Very reactive
Properties of Bases: Taste bitter Contains OH- (the more OH-, the stronger the base) Slippery when wet
Acids and Bases • If the number of H+ ions in a solution is greater than number of OH- ions than the solution is an acid • If the OH- ions are greater than the H+ ions than the solution is a base
pH Scale Ranges from 0-14 Numbers 0-6 represent acids 7 is neutral Numbers 8-14 represent bases 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 strongest acid strongest base
pH Scale • As you move from pH 0 to pH 14, the concentration of H+ DECREASES (10 times each number) • As you move from pH 0 to pH 14, the concentration of OH- INCREASES (10 times each number) • Ex: A substance with pH3 is 100 times stronger acid than a substance with pH 5. A substance with pH 8 is 100 times weaker base than a substance with pH 10.
Buffer • Neutralize acids or bases • Keep the pH from large changes