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 EnergyPotential: 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 =

radioactive isotopes

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 H+ + Cl-Hydochloric hydrogen ion chlorine ion

acid

◦Bases: Proton Acceptors (OH- donor)

◦NaOH Na+ + OH-

Sodium hydroxide sodium ion hydoxide

Proton

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)