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Chemistry of Living Things Properties of Water. Properties of Water. Water : H 2 O Polar molecule due to its shape and uneven distribution of electrons Polar : having a + and - side. Properties of Water. Oppositely charged ends attract forming hydrogen bonds
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Properties of Water • Water: H2O • Polar molecule due to its shape and uneven distribution of electrons • Polar: having a + and - side
Properties of Water • Oppositely charged ends attract forming hydrogen bonds • Waters polarity produces Cohesion and Adhesion
Properties of Water • Cohesion: Water sticking to itself • Adhesion: water sticking to other things
MIXTURES • Water is not always pure. It is often found as part of a mixture. • A mixture is a material composed of TWO OR MORE ELEMENTS OR COMPOUNDS THAT ARE PHYSICALLY MIXED • Ex: salt & pepper mixed, sugar and sand – can be easily separated
SOLUTION Two parts: • SOLUTE: The substance being dissolved • SOLVENT - the substance in which the substance dissolves • Solutions are HOMOGENEOUS(same throughout)Ex. Salt Water • SUSPENSIONS: a mixture in which undisolved materials are so small they are suspended(floating) • Blood is the most common example of a suspension. • Cells & other particles remain in suspension.
Acids and Bases • Water molecules react forming ions • H2OH+(hydrogen) + OH-(Hydroxide) • So what is PH??? • PH: The hydrogen Ion concentration, acidic or basic
pH SCALE • measures the degree of alkalinity(basic) or acidity • Ranges from 0 to 14 • 0 – 6 acidic • 7 neutral • 8-14 basic
Measuring PH • Litmus paper: Acid turns litmus red and Base turns litmus Blue • Wide range Ph paper: tells the exact ph using a color scale