Why is chemistry important?

Chemistry is related to Biology because all the processes that go on in our world and in your body are a result of chemical reactions.

- photosynthesis- digestion- metabolism

Biochemistry: chemistry of living organisms

CHEMISTRY OF LIFE

                                                                      

Everything around us is made up of matter .

Matter: anything that has mass and volume

Mass: amount of matter in an object

Volume: amount of space and object takes up

Weight: force of gravity on mass

States of matter 1. Solid: definite shape and volume

2. Liquid: indefinite shape, definite volume

3. Gas: indefinite shape and volume

Classification of Matter

Classification of matterI. Pure substances: a substance that is identical throughout

A. Element: composed on only one type of atomEx: Na, Pb, Cl, etc …….

- 109 elements - 90 natural- 19 synthetically made in lab, basically radioactive

- most solid- represented by symbols (from Latin)

Ex: lead Pb plumbus Sodium Na natrium Iron Fe ferrium

B. Compound: two or more elements chemically combined in a definite proportion

Ex: H2O, H2O2

CO2, CO O2, O3

** cpds have different properties than original elements that make them

Ex: NaCl sodium: metal, poison

Chlorine: gas, poison

II. Mixture: two or more substances (element or compound)

mixed but not chemically combined

- original substances keep their identities and can be separated out by physical means

Ex: salt water – boil off water and collect salt

Ex of mixtures: salad dressing rocks, sand, water, blood,

earth’s atmosphere (O, N, CO2, Ar, etc)

Two types MixturesA. Solution: mixture where substances are equally distributed

and appear as one substance

Components of a solution

Solute: substance being dissolved

Solvent: substance doing dissolvingex: ice tea mix in waterex: 0.85% NaCl in plasma (water component of blood)

Aqueous solution: water is UNIVERSAL SOLVENT

when two same states of matter: solvent is substance in larger amount

B. Suspension:

mixture where particles are too small to settle and stay suspended due to movement of water molecules

Ex: milk

Example of solution and suspension:

blood: salt in water - solution

blood: cells in saline - suspension

Structure of the AtomAtom: basic unit of matter,

pure substance

Subatomic structure1. Protons – positive, inside nucleus

2. Neutrons- neutral, inside nucleus

3. Electrons- negative, outside nucleus equals the number of protons

( size of nucleus compared to whole atom is like pea in giants stadium )

Atomic number = protonsProtons = Electrons

Atomic mass = protons + neutrons

Isotopes: different form of the same element due to different number of neutrons

• most radioactive (elements with unstable nuclei which break down and emit particles)

Ex: C 12, C13, C14 6 protons 6 protons 6 protons 6 neutrons 7 neutrons 8 neutrons

H1 H2 H3

protium deuterium tritium 1 proton 1 proton 1 proton 0 neutrons 1 neutron 2 neutrons

Uses of Isotopes

- Study age of fossils and rocks C14

- Radiation therapy: cobalt 60, cancercarbon 14, brain tumors

- Medical tests: cobalt 60

Thallium, stress testsIron 59, blood circulationIodine, thyroid tests

BondingChemical bond: process if joining atoms in a compound

• Electrons are subatomic particles involved in bond

• Goal of bond: to complete outer shell and become stable

• To form a compound electrons:- gain- lose- share

Bonding Basics

Bonding Basics

• Atoms try to fill valence shell (orbital) to become stable

• H and He: need 2 valence electrons

• All other atoms: need 8 valence electrons

• Metals lose electrons

• Non metals gain electrons

Types of Bonds1. Ionic: transfer of electron between

metal and non metal

- metal gives electrons to non metal

- ions (charged atoms) formed

Ex: NaCl, MgBr2

- strong magnetic attraction keeps compound together

Types of Bonds

2. Covalent: two non metals share

electrons

- called moleculesex: H2O, CO2

- interparticular forces keep atoms together

Types of Bonds

3. Hydrogen:

weak chemical attraction between polar molecules

WHENEVER BOND IS FORMED A CHEMICAL CHANGE TAKES PLACE

Chemical reaction (change): process in which a chemical change occurs due to bonding

Ex: decaying of apples digestion of food burning of coal decomposition of

plantsrusting of iron

EVERYTHING THAT OCCURS IN LIVING ORGANISMS IS A RESULT OF CHEMICAL

REACTIONS.

WATER AND SOLUTIONS

• universal solvent in organisms • one of few liquid compounds found naturally on earth, most solid

• expands in solid form

• covers > 75% of earth

• most abundant compound in living organisms (human body ~ 70%)

• most important compound in organisms - cells surrounded by it- filled with it- cellular events occur in it)- carries or dissolves other substances

Properties of Water1. Polar molecule (polarity)

Will carry or dissolve other substances in it which are vital for life.

- Hydrophilic: substances that dissolve rapidly in water

*Generally polar molecules or ions (unlike charges highly attracted to each other)

- Hydrophobic: substances that are insoluble in water

*Generally non-polar molecules (water molecules are more attracted to each other than the non polar molecules)

2. Cohesion/Adhesion

• Cohesion: attraction of same substances of same kind (water to water)

• Adhesion: attraction of water to other materials

- oxygen end: negative charge- hydrogen end: positive charge.

The hydrogens of one water molecule are attracted to the oxygen from other water molecules. This attractive force is what gives water its cohesive and adhesive properties.

3. Surface Tension: cohesion of water molecules at the surface of a body of water

- Each molecule in the water drop is attracted to the other water molecules in the drop.

- This causes the water to pull itself into a shape with the smallest amount of surface area, a bead (sphere).

- All the water molecules on the surface of the bead are creating surface tension. (like a large group of people tightly holding hands)

4. Capillary Action adhesion of water

molecules to other substances which allow it to be drawn up the surface of the other subst.

Ex: meniscus

plants pull water

into themselves

water “climbing” up a straw

5. Stores heat efficiently

- absorbs a lot of energy before it will raise its temp.

- retains its heat longer than many other substances

- this property keeps temperature fluctuations to a minimum in order support life on land and in water

IONS AND LIVING CELLSSalt is a very important polar molecule.

- When mixed with water, the ionic bonds are broken and the Na and Cl ions separate (dissociation)

- The charged ends of each ion are attracted to the polar ends of water

- This is very important because ions such as Na, Cl, K, and Ca are involved in many reactions inside the cell

Ionization Process of water (non-ionic) being converted into ions

Result: Separate H+ and OH- ions

H+ combines with water to make H3O+ ion

pH: number of H ions in a solution

Acid: any compound that releases H ions into water- H3O+ (hydronium ion is formed)

ex: hydrochloric acid in water

HCl H+ + Cl-

**** Most reactive ion due to no electrons- attacks bonds in many molecules

Base: compound that releases OH- ions into waterEx: NaOH Na+ + OH-

• Neutralization reaction: production of H2O from mixture of strong acid and base

neutral H = OH

acidic H > OH

basic, alkaline H < OH

Buffer

solution which resists changes in pH when small

quantities of an acid or an alkali are added to it

• Important in maintaining pH in organisms

The pH scale

Acid: below ph 7 (more H ions)

Base: above pH 7 (more OH ions)

IMPORTANCE OF PH:

• most reactions in organisms can only occur with enzymes

• enzymes very pH specific

***failed kidney function is most often reason for inability to maintain normal blood pH