WATERWATER

Its magical powers and why it Its magical powers and why it is so important in biology.is so important in biology.

WATER MOLECULEWATER MOLECULE

-- 1 oxygen atom and 2 hydrogen atoms share pairs 1 oxygen atom and 2 hydrogen atoms share pairs of electrons (covalent bonds)of electrons (covalent bonds)

-- Since oxygen is larger and has 8 protons (+) to pull Since oxygen is larger and has 8 protons (+) to pull on the 10 electrons it has the tendency to pull (hog) on the 10 electrons it has the tendency to pull (hog) the electrons from the smaller hydrogen atoms with the electrons from the smaller hydrogen atoms with only 1 protononly 1 proton

WATER MOLECULEWATER MOLECULE

• The result of this pull causes the region The result of this pull causes the region around the oxygen atom to have a slightly around the oxygen atom to have a slightly negative charge and the regions around the negative charge and the regions around the hydrogen atoms to have a slightly positive hydrogen atoms to have a slightly positive charge.charge.

POLARITYPOLARITY

• Defined as an uneven pattern of Defined as an uneven pattern of chargecharge

This uneven pattern of charge gives This uneven pattern of charge gives water many special characteristics.water many special characteristics.

CHARACTERISTICS OF CHARACTERISTICS OF WATERWATER

1.1. DISSOLVES IONIC COMPOUNDSDISSOLVES IONIC COMPOUNDS the the charges of the water molecule pull charges of the water molecule pull apart the weak ionic bondsapart the weak ionic bonds

2.2. DISSOLVES other POLAR DISSOLVES other POLAR SUBSTANCESSUBSTANCES- such as sugars and - such as sugars and proteinsproteins

CHARACTERISTICS OF CHARACTERISTICS OF WATERWATER

3.3. WATER BONDS TIGHTLY TO ITSELFWATER BONDS TIGHTLY TO ITSELF- the - the hydrogen of one water molecule is hydrogen of one water molecule is attracted to the oxygen of another attracted to the oxygen of another molecule called a molecule called a HYDROGEN BOND- HYDROGEN BOND-

CHARACTERISTICS OF CHARACTERISTICS OF WATERWATER

COHESION- COHESION- attractive forces between attractive forces between like particles like particles

Examples- why water appears in Examples- why water appears in drops, why some animals can float drops, why some animals can float on water “SURFACE TENSION”on water “SURFACE TENSION”

CHARACTERISTICS OF CHARACTERISTICS OF WATERWATER

ADHESION- the attraction of non ADHESION- the attraction of non similar substances to one another.similar substances to one another.

CAPILLARY ACTION- pulls water up CAPILLARY ACTION- pulls water up into small tubes-into small tubes-

CHARACTERISTICS OF CHARACTERISTICS OF WATERWATER

HIGH HEAT CAPACITY- “temperature HIGH HEAT CAPACITY- “temperature moderation”- water must gain or moderation”- water must gain or lose a relatively large amount of lose a relatively large amount of energy for its temperature to change energy for its temperature to change

Examples- body temperature, “ocean Examples- body temperature, “ocean effect”effect”

CHARACTERISTICS OF CHARACTERISTICS OF WATERWATER

• WATER EXPANDS WHEN IT FREEZES- WATER EXPANDS WHEN IT FREEZES- ice is less dense than water and ice is less dense than water and therefore it floats on top of the watertherefore it floats on top of the water

BROWNIAN MOTIONBROWNIAN MOTION

BROWNIAN MOTION- all objects have BROWNIAN MOTION- all objects have energy of motion called kinetic energy of motion called kinetic energy. A moving particle of matter energy. A moving particle of matter moves in a straight line until it moves in a straight line until it collides with another particle. After collides with another particle. After the collision each particle rebounds the collision each particle rebounds into another directioninto another direction

DIFFUSIONDIFFUSION

• Random movement of particles from Random movement of particles from an area of high concentration to an an area of high concentration to an area of low concentrationarea of low concentration

-- Diffusion is slow because it relies on Diffusion is slow because it relies on random motionrandom motion

DIFFUSIONDIFFUSION

3 ways to increase diffusion3 ways to increase diffusion1. increase temperature (particles 1. increase temperature (particles will move faster)will move faster)2.2. increase pressure ( particles increase pressure ( particles will collide more often )will collide more often )

3.3. increase the concentration increase the concentration ( more particles will be involved in the ( more particles will be involved in the collisions )collisions )

DIFFUSIONDIFFUSION

• Diffusion will continue until the Diffusion will continue until the random movement of particles INTO random movement of particles INTO the area equals the random the area equals the random movement of particles OUT of the movement of particles OUT of the area.area.

• DYNAMIC EQUILIBRIUM-DYNAMIC EQUILIBRIUM-

Why is diffusion important to Why is diffusion important to living thingsliving things

• Cells use diffusion to get particles Cells use diffusion to get particles into the cell.into the cell.

• Examples- water, oxygen, COExamples- water, oxygen, CO22

MIXTURES AND SOLUTIONSMIXTURES AND SOLUTIONS

MIXTUREMIXTURE

a combination of substances in a combination of substances in which the individual components which the individual components retain their own properties.retain their own properties.

EXAMPLES;EXAMPLES;

SOLUTIONSOLUTION

Mixture in which one or more substances Mixture in which one or more substances are distributed evenly in another substanceare distributed evenly in another substance

Examples:Examples:

SOLUTE- the substance that YOU put into the SOLUTE- the substance that YOU put into the solution (gets dissolved)solution (gets dissolved)

SOLVENT- the substance that does the SOLVENT- the substance that does the dissolvingdissolving

How do we measure solutions?How do we measure solutions?

CONCENTRATION- amount of solute CONCENTRATION- amount of solute dissolved in a fixed amount of dissolved in a fixed amount of solution. (usually 100mL)solution. (usually 100mL)

SATUARATED SOLUTION- when no SATUARATED SOLUTION- when no more solute can be dissolved in the more solute can be dissolved in the solutionsolution

Differences between a mixture and Differences between a mixture and solutionsolution

Solution has a uniform colorSolution has a uniform color Mixture is much easier to separate Mixture is much easier to separate

out the substancesout the substances

ACIDS AND BASESACIDS AND BASES

Created by the DISSOCIATION of a Created by the DISSOCIATION of a water molecule. DISSOCIATION- is the water molecule. DISSOCIATION- is the breaking apart of a water moleculebreaking apart of a water molecule

HH22O O H H++ + OH + OH--

OHOH-- is known as the HYDROXIDE ION is known as the HYDROXIDE ION and a high number of these makes the and a high number of these makes the solution a base (alkaline)solution a base (alkaline)

ACIDS AND BASESACIDS AND BASES

The H+ ion can bond with other The H+ ion can bond with other water molecules to form a water molecules to form a HYDRONIUM ION HHYDRONIUM ION H33OO++

A high amount of HYDRONIUM IONS A high amount of HYDRONIUM IONS makes the solution an acid.makes the solution an acid.

pH SCALEpH SCALE

7

0 14

6 8

5 9

113

pH SCALEpH SCALE

We measure the acidity or alkalinity We measure the acidity or alkalinity (basicity) by finding the (basicity) by finding the ratioratio of of hydroxide ions to hydronium ions.hydroxide ions to hydronium ions.

We measure it on a pH scale of 0 to We measure it on a pH scale of 0 to 14 with 7 being neutral.14 with 7 being neutral.

Pure water has a pH of 7.Pure water has a pH of 7.

ACIDACID

ACID- has a greater number of ACID- has a greater number of hydronium ionshydronium ions

-have sour taste (examples)-have sour taste (examples)

-highly corrosive to metal-highly corrosive to metal

- 0 to 6.9 on the pH scale- 0 to 6.9 on the pH scale

BASEBASE

BASE- has a greater number of OH- BASE- has a greater number of OH- ionsions

-has a bitter taste (examples)-has a bitter taste (examples)

- highly corrosive to organic - highly corrosive to organic mattermatter

-7.1 to 14 on the pH scale-7.1 to 14 on the pH scale

-feels slippery-feels slippery

pH SCALEpH SCALE

How to use the pH scale.How to use the pH scale.

Moving one number away from neutral Moving one number away from neutral increases the strength 10Xincreases the strength 10X

Example:Example:

In order to NEUTRALIZE an acid it is In order to NEUTRALIZE an acid it is best to use a base of the same best to use a base of the same strength.strength.

Example:Example: