THE CHEMISTRY OF LIFE

ORGANIC AND INORGANIC CHEMISTRY

INORGANIC CHEMISTRYMatter Water

What are we made of?

• Matter1. Matter takes up space and has mass.2. All living and nonliving matter is composed of 92 naturally-occurring basic elements (Periodic Table)3. Elements cannot be broken down to substances with different chemical or physical properties.4. Six elements (C, H, N, O, P, S) make up 98% of living things.

• Atomic Structure1. Chemical and physical properties of atoms (e.g., mass) depend on the subatomic particles.

a. Different atoms contain specific numbers of protons, neutrons, and electrons.

b. Protons and neutrons are in nucleus of atoms; electrons move around nucleus.

c. Protons= positively charged particles; Neutrons= no charge

d. Electrons= negatively charged particles.2. ATOMIC MASS= sum of its protons and neutrons.3. All atoms of an element have the same number of protons, the atom’s ATOMIC NUMBER

Chemical Element- pure substance that consists entirely of one type of atom.• Represented by one- or two- letter symbols • Example: C- carbon, Na- Sodium, H- Hydrogen

Isotopes- Atoms of the same element that differ in the number of neutrons they contain• Remember, mass number depends on the # of protons

and neutrons. • How are all of the isotopes of an element similar?

• Because they have the same number of electrons, all isotopes of an element have the same chemical properties.

Radioactive isotopes

• Some Isotopes are RADIOACTIVE• Their nuclei are UNSTABLE and break down at a constant rate over time. • Radiation these isotopes give off can be dangerous but the important scientific

and practical uses are:

1. Geologists can determine the age of rocks and fossils by analyzing the isotopes found in them.

2. used to detect and treat cancer and to kill bacteria that cause food to spoil. 3. used as labels or “tracers” to follow the movements of substances within

organisms.

Radiation is the transfer of heat energy by electromagnetic wave motion.

Earth is surrounded by radiation. we are exposed to radon, a radioactive gas from uranium found in soil

dispersed in the air radioactive potassium in our food and water uranium, radium, and thorium in the Earth's crust cosmic rays and the sun.

These types of radiation are called Natural or Background Radiation.

Chemical Compounds- substance formed by the chemical combination of two or more elements in definite proportions. • Definite proportions showing as a

chemical formula.

The physical and chemical properties of a compound are usually very different from those

of the elements from which it is formed.

CHEMICAL BONDS

Ionic Bonds• One or more electrons are transferred from one atom to

another• Ions- positive or negative charged atoms

Covalent Bonds• Electrons are shared by atoms instead of being transferred• Sharing can consists of one or more electrons consisting of

single, double, or triple bonds• Molecules are formed from atoms that are joined together by

covalent bonds. • Van Der Waals Forces- molecules are close together, a slight

attraction can develop between the oppositely charged regions of nearby molecules. (INTERMOLECULAR FORCES)

PROPERTIES OF WATER

POLARITY

• A molecule in which the charges are unevenly distributed is said to be “polar” because the molecule is like a magnet with two poles.

• Partial charges on a polar molecule are written in parentheses (-) and (+) to show that they are weaker than the charges on ions.

• Attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge= HYDROGEN BOND

Give Life’s most important molecules many of it’s unique characteristics.

Hydrogen Bonding

WATER

THE SOLVENT OF LIFE

VAN DER WAALS FORCE

• SLIGHTLY POLAR SIDE OF ONE MOLECULE BEING

ATTRACTED ANOTHER MOLECULE WITH THE SLIGHTLY

OPPOSITE CHARGE

• NOT A COVALENT BOND….JUST A LITTLE ATTRACTION

• HYDROGEN BONDS ARE A TYPE OF VAN DER WAALS

FORCE

*****HYDROGEN BOND*****

• WEAK ATTRACTION BETWEEN HYDROGEN

ATOM OF ONE MOLECULE (IT WILL BE THE

SLIGHTLY POSITIVE SIDE) AND AN OXYGEN,

NITROGEN OR SULFUR BOND OF ANOTHER

MOLECULE (WHICH WILL BE THE SLIGHTLY

NEGATIVE SIDE).

PROPERTIES OF WATER•VERSATILITY AS A SOLVENT

• POLARITY AND HYDROGEN BONDS

•COHESIVE AND ADHESIVE BEHAVIOR

• CAPILLARY ACTIONDEFY GRAVITY

•EXPANSION UPON FREEZING

• SOLID WATER FLOATS

•HIGH SPECIFIC HEAT (HEAT CAPACITY)

• ENABLES TEMPERATURE MODERATION

MIXTURE, SOLUTIONS AND SUSPENSIONS…OH MY!

A LITTLE BIT ABOUT WATER• WATER IS THE BIOLOGICAL MEDIUM ON EARTH

• UNIVERSAL SOLVENT

• SOLVENT: THE SUBSTANCE THAT THE SOLUTE (SALT) IS DISSOVLED IN (WATER)

• SOLUTE: SUBSTANCE (SALT) THAT IS DISSOLVED IN A LIQUID

• SOLUTION: WHEN SOLUTES ARE UNIFORMLY DISTRIBUTED THROUGHOUT A WATER

SOLVENT

• WATER IS A VERSATILE SOLVENT DUE TO ITS POLARITY

• MOST CELLS ARE SURROUNDED BY WATER, AND CELLS THEMSELVES ARE

ABOUT 70-95% WATER

• THE ABUNDANCE OF WATER IS THE MAIN REASON THE EARTH IS HABITABLE

•MIXTURES

– PHYSICALLY, NOT CHEMICALLY MIXED

COMPOUNDS

–NOT NECESSARILY EVENLY DISTRIBUTED

–HOMOGENOUS MIXTURES

• EVENLY DISTRIBUTED

• CANNOT SEE THE DIFFERENT PARTS

• SOLUTIONS ARE HOMOGENOUS MIX.

–HETEROGENOUS MIXTURES

• NOT UNIFORMLY DISTRIBUTED

• YOU CAN SEE THE PARTS

• SUSPENSIONS ARE HETEROGENOUS MIX.

SPECIAL TYPES OF MIXTURES…

• SOLUTION

• HOMOGENOUS MIXTURE

• COMPONENTS ARE UNIFORMLY DISTRIBUTED

• SOLUTES AND SOLVENTS

• EX. SALT WATER

• SUSPENSION

• MIXTURE OF WATER AND NON-DISSOLVED MATERIAL

• SOME OF THE MOST BIOLOGICALLY IMPORTANT

SUBSTANCES ARE BOTH SOLUTIONS AND SUSPENSIONS

• EX. BLOOD

WATER AS THE UNIVERSAL SOLVENT

•WATER IS AN EFFECTIVE SOLVENT BECAUSE IT READILY FORMS

HYDROGEN BONDS

•WHEN AN IONIC COMPOUND IS DISSOLVED IN WATER, EACH ION IS

SURROUNDED BY A SPHERE OF WATER MOLECULES, A HYDRATION

SHELL

•WATER CAN ALSO DISSOLVE COMPOUNDS MADE OF NONIONIC POLAR

MOLECULES

•EVEN LARGE POLAR MOLECULES SUCH AS PROTEINS CAN DISSOLVE

IN WATER IF THEY HAVE IONIC AND POLAR REGIONS

Na+

Na+

Cl–Cl–

+

+

+

+

+

+

++

–

–

–

–

–

–

–

–

–

–

–

ACIDS AND BASES

• WHAT DO YOU KNOW?

ACIDS• AN ACID IS ANY SUBSTANCE THAT INCREASES THE H+

CONCENTRATION OF A SOLUTION

–ADDS H+ IONS TO WATER

–TASTE SOUR

–TURN CABBAGE JUICE RED

–TURN BLUE LITMUS PAPER RED

• STRONG ACIDS (LOW PH)

–DISSOCIATE COMPLETELY IN WATER

–ADDS LOTS OF H+ IONS

–HYDROCHLORIC ACID HCL

–HCL H+ AND CL-

• WEAK ACIDS (PH SLIGHTLY BELOW 7)

–PARTIALLY DISSOCIATE IN WATER

–ONLY ADD A LITTLE BIT OF H+ IONS

–COFFEE, TOMATO JUICE, ACETIC ACID

  H         O        |       //H--C—C        |       \\       H         O-

CH3COOH = CH3COO- + H+

BASES• A BASE IS ANY SUBSTANCE THAT REDUCES THE H+

CONCENTRATION OF A SOLUTION

• ADDS HYDROXIDE IONS (OH-) TO WATER• OH- IONS BIND TO ANY FREE H+ IONS TO MAKE…A MOLECULE OF WATER• THIS DOES WHAT TO THE CONCENTRATION OF H+ IONS ION THE WATER?\

• DECREASE H+ ION CONCENTRATION, THEREFORE, MAKING IT BASIC

• CHARACTERISTICS:• TASTE BITTER • FEELS SLIMY • TURNS CABBAGE JUICE YELLOW, GREEN OR BLUE DEPENDING UPON THE

SOLUTION CONCENTRATION • TURNS RED LITMUS PAPER BLUE

• STRONG BASES (PH HIGH- CLOSE TO 14)• COMPLETELY DISSOCIATE IN SOLUTION• ADDS LOTS OF OH- ION TO SOLUTIONS• NAOH SODIUM HYDROXIDE NAOH NA+ AND OH-

• WEAK BASES• PARTIALLY DISSOCIATE IN WATER • ADDS ONLY A FEW OH- TO SOLUTION• AMMONIA NH3

STRONG ACIDS AND BASES

HCl - hydrochloric acid HNO3 - nitric acid H2SO4 - sulfuric acid HBr - hydrobromic acid HI - hydroiodic acid HClO4 - perchloric acid

LiOH - lithium hydroxide NaOH - sodium hydroxide KOH - potassium hydroxide RbOH - rubidium hydroxide CsOH - cesium hydroxide

DISSOCIATE COMPLETELYWhat do you notice?

THE PH SCALE•THE PH OF A SOLUTION IS DETERMINED BY THE RELATIVE

CONCENTRATION OF HYDROGEN IONS H+

–SO IT IS REALLY MEASURING HOW ACIDIC SOMETHING IS

– FORMULA IS..

–PH=-LOG[H+]

• NEGATIVE MEANS OPPOSITE, THIS IS WHY A LOW PH HAS MORE H+ IONS

• [X] MEANS CONCENTRATION

•ACIDIC SOLUTIONS HAVE PH VALUES LESS THAN 7

–MORE H+ IONS

•BASIC SOLUTIONS HAVE PH VALUES GREATER THAN 7

–MORE OH- IONS, LESS H+ IONS

•MOST BIOLOGICAL FLUIDS HAVE PH VALUES IN THE RANGE

OF 6 TO 8

BUFFERS

•THE INTERNAL PH OF MOST LIVING CELLS MUST REMAIN CLOSE TO PH 7

•BUFFERS ARE SUBSTANCES THAT MINIMIZE CHANGES IN CONCENTRATIONS OF H+ AND OH- IN A SOLUTION

•WEAK ACIDS ARE A BUFFER FOR STRONG BASES

•WEAK BASES ARE A BUFFER FOR STRONG ACIDS

•MOST BUFFERS CONSIST OF AN ACID-BASE PAIR THAT REVERSIBLY COMBINES WITH H+