CHAPTER 2aCHEMISTRY OF LIFE

* All things in the universe are comprised of MATTER- Anything that occupies space and has MASS

* MASS - is the quantity of matter that an object has. Gravity plus mass = weight

I. COMPOSITION OF MATTER:

four states of matter SOLID - particles are tightly packed

- particles move very little

- do not need a container

LIQUID - particles loosely arrange - particles move randomly - particles conform to containerGAS - particles most loosely arranged

- particles move the most- -particles fill a container

PLASMA - exists between solid and liquid

States of Matter

A. ATOMS:

-Smallest unit of matter that cannot be broken down by chemical means.

-The nature and properties of the atom determine the structure and behavior of the matter that its making

--Atoms consists of three main parts…

NUCLEUS- The core of the atom, consists of two kinds of subatomic particles…

1. PROTON (+) 2. NEUTRON (no charge)

OUTSIDE “CLOUD”- particles that are found moving about the nucleus at tremendous speeds.

3. ELECTRONS (-)

- The electron cloud is broken down into separate section called LEVELS or SHELLS.

- Each of the surrounding levels is only able to hold a certain number of electrons.

-Electrons nearest the nucleus have low energy, where those away from the nucleus have higher energy.

**AN ATOM HAS EQUAL NUMBERS OF PROTONS AND ELECTRONS, THEREFORE THE ELECTRICAL CHARGES OFFSET EACH OTHER THE NET CHARGE OF AN ATOM IS ZERO**

*IONS- Those atoms which DO have a charge because of either the loss or gain of electrons…

B. ELEMENTS:

-Substances made of only one type of atom.

-Each element has a symbol, they are all represented in the PERIODIC TABLE.

-Over 114 identified elements, most are

naturally occurring, 92, the rest are man made.

Place periodic table here

ATOMIC NUMBER - Number of protons in the nucleus

6 12.01 MASS NUMBER /ATOMIC WT- Sum of the protons and neutrons in an atom vs. average of all the neutronsC

CARBON

SYMBOL - Name abbreviation

ELEMENT NAME

- ISOTOPES are atoms of the same element that have a different # of neutrons.

II. CHEMICAL BONDING

A. COMPOUND is two or more elements that are joined by chemical bonds

-In compounds, the proportions of individual atoms are fixed

-Shown using...

- A CHEMICAL FORMULA is used to show the binding and proportions of atoms that form compounds.

-A compound differs in physical and chemical properties from the elements that composed it.

Sodium = solid

Chlorine = gas

Hydrogen = gas

Oxygen = gas

Water = liquid

Salt = solid

B. Types of bonds:

1. COVALENT BONDS 2. IONIC BONDS

3. HYDROGEN BONDS 4.

1. COVALENT BONDS:- Formed by two atoms that

share one or more pair of electrons.

-A MOLECULE is a group of atoms held together by covalent bonds.

Covalent Bonds

http://www.youtube.com/watch?v=1wpDicW_MQQ

2. IONIC BONDS:

-A bond formed from the lose or gain of electrons, which causes the atoms to become “charged”-An ION is a charged particle/atom

3. HYDROGEN BONDS:- A weak chemical attraction between hydrogen and fluorine, oxygen, or nitrogen.

-Type of VAN DER WAALS FORCE.

III. MIXTURES:A. MIXTURE is a substance where

the combined substances retain their original chemical properties and may have different proportions of the substances that make them up.

B. Types Of Mixtures

1. SOLUTION:-A solution is mixture in which one or

more substances are uniformly distributed in another substance.

-The SOLUTE is the substance being dissolved in the solution. (may be ions, atoms, or small molecules.)

-The SOLVENT is the substance in which the solute is dissolved.

Solute to Solvent Ratio

CONCENTRATION - Ratio of solute to a set amount of solvent.

high concentration= high solute low solvent

Dilute= low solute high solvent

SATURATED - When you get to a point where no more solute can be dissolved within the solvent, at a given temperature.

*-Biologically the most important solutions are those in which gases, liquids, and solids, are dissolved in water.

These are referred to as AQUEOUS SOLUTIONS.

Water is often referred to as the “Universal Solvent”

2. SUSPENSIONS:

-A SUSPENSION is a mixture in which particles spread through a liquid or a gas but settle out over time.

-The particles in a suspension are larger than solute particles in a solution.

LAVA LAMP

III. ACIDS AND BASES:

A. ACIDS: -ACIDS - Compounds that release hydrogen ions

when dissolved in water.- ACIDIC SOLUTIONS are those which contain

higher concentrations of hydrogen ions than hydroxide ions (H+ > OH-)

-Acids tend to have a sour taste, can burn skin, eyes, mucous membranes (even fumes), very high concentrations are corrosive ****NOT always harmful!!

B. BASES:ALKALINITY is a measure of the

relative amounts of HYDROXIDE IONS (OH-) dissolved in a solution.

-A BASIC SOLUTION is a solution that contains more hydroxide ions than hydronium ions.

-The term ALKALINE also refers to basic substances

-Bases have a bitter taste, tend to feel slippery

C. pH:-Scientists have developed a scale

for measuring the relative concentration of hydronium and hydroxide ions in a solution.

-Called the pH SCALE, it ranges from

0 to 14 0-6.9= an acidic solution 7 = neutral 7.1-14= a basic or alkaline solution

1. Testing pH

-Acidity can be tested using...

1. electronic devises

2. LITMUS PAPER

3. pH PAPER

**- Control of pH is often very important for the survival of an organism.

pH SCALE

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IV. CHEMICAL REACTIONS:A. CHEMICAL REACTION is the process of

breaking chemical bonds or of forming new bonds or both.

-In a chemical reaction the atoms of the REACTANTS combine to form the PRODUCTS of the reaction.

Na+ and Cl- yields NaCl

-CHEMICAL EQUATIONS show how reactants change during chemical reactions.

B. RULES FOR BALANCING EQUATIONS

1. The quantity of the products must equal the quantity of the reactants.

2. Subscripts CANNOT be changed

H20

3. Subscripts only apply to the element that they follow.

CO2= 1 carbon and 2 oxygen

In chemical reactions, matter cannot be created or destroyed – CONSERVATION OF MASS.

2CO2= 2 carbon and 4 oxygen

4. Numbers placed in front of a compound carry through the whole compound.

5. Numbers before or after parenthesize get carried through to all the elements

2(NaCl2)2 = 4 Na and 8 Cl

6. Balance O and H LAST!

BALANCING EQUATIONS EXAMPLE

CO2 + H2O YIELDS C6H12O6 + O2

6CO2 + H2O YIELDS C6H12O6 + O2

6CO2 + 6H2O YIELDS C6H12O6 + O2

6CO2 + 6H2O YIELDS C6H12O6 + 6O2