CH 2: CHEMISTRY
Matter
◦ What is it?
◦ Anything that takes up space, has mass, and made up of
atoms.
◦ What are the 3 states?
Energy
◦ What is it?
◦ Invisible magic?
◦ No!
◦ Invisible? Yes!
◦ It is the ability to put matter into motion.
◦ “INVISIBLE POWER”
Kinetic Energy Vs. Potential Energy
Potential: Stored Energy
Kinetic: Energy of motion
How do we obtain Energy?
◦ We get energy by eating food which gets broken
down in our stomach into useable components.
These smaller parts keep getting broken down
creating ATP which later can be broken down
into ADP releasing energy.
◦ Energy is stored as ATP (adenosine triphosphate)
Energy Conversions
◦ Chemical Energy is converted in the body (breaking down food)
to mechanical energy(i.e. muscle movement) and electrical
energy (i.e. nerve impulses)
Energy Conversion
Inefficiency
◦ Heat is given off as “Thermal Energy "during energy
conversations.
◦Why is this good?
◦ This heat that is given off allows us to be warm blooded
animals and maintain our body temperature.
◦ Helps to speed up other chemical reactions in the body.
Composition of Matter
◦ All matter is composed of a limited number of
elements (~112 known and 6 extremely rare man
made radioactive elements)
◦ Elements are composed of identical atoms.
Atoms of each element are different.
Elements
◦ Each element is composed of many identical
atoms.
◦ Video Clip
◦Atoms
◦ Nucleus (Protons (+) and Neutrons (n0))
◦ Electrons (-) (found in electron cloud around
nucleus)
Atomic Structure
◦Atoms
◦ Nucleus (Protons (+) and Neutrons (n0))
◦ Electrons (-) (found in electron cloud around nucleus)
Major Elements in the Human
Body
◦ Oxygen: 65% - Essential for breathing,
breakdown of sugar (glucose) and other
food fuels allowing for ATP to be released.
◦ Carbon: 18.5% - Major component of all our
organic matter (carbohydrates, lipids (fats),
proteins, and nucleic acids (DNA))
◦ Hydrogen: 9.5% - Found in organic matter
and influences pH
◦ Nitrogen: 3.2% - Found in proteins and nucleic
acids.
Other Elements:
◦ Phosphorous: Forms part of ATP and ADP, Found
in bones, teeth, and nucleic acids.
◦ Sodium: Important for water balance and nerve
impulses and muscle contractions.
◦ Calcium: Important for bones, teeth, muscle
contraction, neural transmission, and blood
clotting.
◦ Iron: Important for oxygen uptake in the blood by
hemoglobin.
Isotopes
◦ Have the same number of protons and electrons as their atom
family but different number of neutrons.
◦ “Skinny” atoms – less neutrons
◦ “Overweight” atoms – extra neutrons
◦ The heavier isotopes become unstable =
isotopes
radioactive
Radioactive Isotopes
◦ Involve the ejection of particles from the atoms' nucleus and are
damaging to living cells.
◦ Used in minute amounts to tag biological molecules to be
followed throughout the body for medical diagnosis and
treatment.
Molecules
◦ 2 or more of the same atom combine together
Compounds
◦ 2 or more different atoms bind together.
Ionic Bond
◦ Bonds formed between atoms when electrons
are completely transferred from one atom to the
to the other creating:
◦ CHARGED ATOMS = IONS
Covalent Bonds
◦ Bonds formed when atoms share electrons to become stable.
Hydrogen Bonds
• Very weak bonds between
hydrogen and oxygen (or nitrogen)
atom.
◦ Creates water’s special surface tension
Synthesis Reactions
◦ When atoms or molecules come together to
create a bigger more complex molecule.
◦ Synthesis= Create
Decomposition Reaction
◦ The breakdown of a molecule into smaller
molecules, atoms, or ions.
Exchange Reactions
◦ When atoms or molecules switch partners.
Are chemical reactions
reversible?
◦ Most chemical reactions are reversible. New
bonds can be broken and rearranged to go
back to the original formula.
◦ Double arrow represents a reversible reaction.
Organic Molecules VS.
Inorganic Molecules
◦ Organic Molecules = Carbon containing
molecules
◦ Ex: Carbohydrates, Lipids, Proteins, and Nucleic
Acids
◦ Inorganic Molecules= Non-carbon containing
molecules
◦ Typically small molecules
◦ Ex: Salts, water, and many (not all ) acids and bases
Water
◦ Accounts for 2/3 of the bodies weight
◦ Has very special properties:
◦ High Heat Capacity
◦ Polarity
◦ Chemical Reactivity
◦ Cushioning
High Heat Capacity
◦ It can absorb and release large amounts of heat
before it’s temperature changes.
◦ Why would this be a good thing for our body
temperature?
◦ Water’s high heat capacity allows us to withstand
intense sun exposure, very cold winter winds, or
from heat generated from internal reactions.
Polarity/Solvent Properties
◦ Water is the “UNIVERSAL SOLVENT”
◦ Solvent = liquid or gas in which smaller amounts of
substances known as solutes can be dissolved or
suspended.
◦ Solutes can be: gases, liquids, or solids
◦ How does this affect us?
◦ Molecules cannot chemically react unless in solution (in water)
◦ All of our necessary chemical reactions occur in water!!!
◦ Water also transports gases and wastes such as in our blood
and between cells.
◦ Special lubricants that allow our bones to move within joints
need water.
Chemical Reactivity
◦ Water is needed to breakdown large molecules
such as carbohydrates in our foods through
hydrolysis.
◦ Hydrolysis= addition of water to breakdown
Cushioning
◦ Water serves a protective function.
◦ Fluid around our brain (cerebrospinal fluid)
cushions our brain from trauma.
◦ Amniotic fluid- surrounds a developing baby.
Salts
◦ A salt is a IONIC compound containing two ions a cation (H+)
and an anion (OH-) that are joined together like magnets.
◦ Vital to body functions such as nerve impulses, muscle
contractions, and oxygen transport in blood by hemoglobin.
◦ When salts are dissolved in water they dissociate into electrolytes.
◦ Ions serve as electrolytes which are substances that can conduct
electricity.
◦ Without electrolytes virtually nothing in the body would work.
Acids and Bases
◦ Acids and bases are also electrolytes since they
also dissociate in water.
◦ Acids: Proton Donors
◦ HCl
Hydochloric
acid
Proton
H+

+
Clchlorine ion
hydrogen ion
◦ Bases: Proton Acceptors (OH- donor)
◦ NaOH
Sodium hydroxide

Na+
sodium ion
+
OHhydoxide
pH Scale
◦ Based on the number of hydrogen ions in
solution.
◦ The LOWER the pH the more ACIDIC it is
◦ pH of 7 is Neutral (Distilled Water)
◦ The HIGHER the pH the less ACIDIC or more
BASIC it is.
Buffers
◦ Since living cells are extremely sensitive to slight
pH changes, BUFFERS are used to help regulate
pH changes along with the kidneys and the
lungs.
◦ Normally blood pH varies from 7.35-7.45.
◦ However, if blood pH were to change even a
few tenths of a pH unit from these limits death
becomes a real possibility.
◦ Bicarbonate (Buffer in blood)