The Chemistry of Life Properties of Water The

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The Chemistry of Life Properties of Water

The Chemistry of Life Properties of Water

The Water Molecule • Neutral Charge – ZERO • Have no charge • Have

The Water Molecule • Neutral Charge – ZERO • Have no charge • Have an Equal number of p+ and e • Charges aren’t evenly distributed

The Water Molecule • Polarity – A water molecule is polar because there is

The Water Molecule • Polarity – A water molecule is polar because there is an uneven distribution of electrons between the oxygen and hydrogen atoms. (-) (+)

Hydrogen Bonds & Covalent Bonds • Polar water molecules act like magnets and attract

Hydrogen Bonds & Covalent Bonds • Polar water molecules act like magnets and attract each other • Hydrogen Bonds – Bonds between two water molecule • Covalent Bonds – Bonds between the atoms within the same water molecule

Hydrogen Bonds & Covalent Bonds “Stronger” Bond “Weaker” Bond copyright cmassengale

Hydrogen Bonds & Covalent Bonds “Stronger” Bond “Weaker” Bond copyright cmassengale

You Try… Draw a water molecule and label the hydrogen bonds and covalent bonds.

You Try… Draw a water molecule and label the hydrogen bonds and covalent bonds.

Cohesion & Adhesion • Cohesion - the attraction between molecules of the same substance

Cohesion & Adhesion • Cohesion - the attraction between molecules of the same substance (e. g. water). • Adhesion - attraction between H 2 O molecules and different molecules

Capillarity • Cohesion & adhesion produce Capillarity (upward movement against gravity of water through

Capillarity • Cohesion & adhesion produce Capillarity (upward movement against gravity of water through small tubes) Question: How do plants make use of Capillarity?

Surface Tension • Surface Tension - is the measure of how difficult it is

Surface Tension • Surface Tension - is the measure of how difficult it is to stretch or break the surface of a liquid • Allows some insects and spiders to walk on water.

Solutions & Suspensions • Water is usually part of a mixture. • Because so

Solutions & Suspensions • Water is usually part of a mixture. • Because so many things dissolve in water, it is called the Universal Solvent • There are two types of mixtures: – Solutions – Suspensions

Properties of Solutions • Ionic compounds disperse as ions in water (+ions & -ions

Properties of Solutions • Ionic compounds disperse as ions in water (+ions & -ions spread out among polar water molecules) • Solutions are Evenly distributed mixtures • SOLUTE – Substance that is being dissolved • SOLVENT – Dissolving Substance for the solute

Ionic Solutions Question: What is the solute? What is the solvent?

Ionic Solutions Question: What is the solute? What is the solvent?

Suspensions • Substances that don’t dissolve but separate into tiny pieces. • Water keeps

Suspensions • Substances that don’t dissolve but separate into tiny pieces. • Water keeps the pieces suspended so they don’t settle out. • Blood & Cytoplasm are suspensions

Acids, Bases & p. H • 1 water molecule in 550 million naturally dissociates

Acids, Bases & p. H • 1 water molecule in 550 million naturally dissociates into a Hydrogen Ion and a Hydroxide Ion H 2 O H+ Hydrogen Ion Acid + OH - Hydroxide Ion Base

The p. H Scale • • • Indicates the concentration of H+ ions Ranges

The p. H Scale • • • Indicates the concentration of H+ ions Ranges from 0 – 14 p. H of 7 is neutral p. H 0 up to 7 acid … H+ p. H above 7 to 14 base… OHEach p. H unit represents a factor of 10 X change in concentration

Acids • Strong Acid = p. H 1 -3 • High in H+ ions

Acids • Strong Acid = p. H 1 -3 • High in H+ ions • Lower number of OH- ions

Bases • Strong Base = p. H 11 – 14 • High in OHions

Bases • Strong Base = p. H 11 – 14 • High in OHions • Lower in number of H+ ions

Buffers • Weak acids or bases that react with strong acids or bases •

Buffers • Weak acids or bases that react with strong acids or bases • Made by the body • Prevent sharp, sudden changes in p. H (keep p. H neutral) Weak Acid Weak Base

Other KEY Properties Of Water • high heat capacity - lakes and oceans stabilize

Other KEY Properties Of Water • high heat capacity - lakes and oceans stabilize land air temperatures – A LOT OF ENERGY NEEDED TO RAISE TEMPERATURE • ice floats - lakes and oceans don’t freeze solid from bottom up – LESS DENSE AS A SOLID • it evaporates - allows our bodies to release excess heat – HOMEOSTASIS YOU NEED 8 OUNCES OF WATER FOR EACH 25 POUNDS OF BODY WEIGHT!!!!!!

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