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Anatomy Chapter 2 Outline 1. MATTER: the “stuff” of the universe. It’s anything that occupies space and has mass. a. Matter exists in three main states: i. SOLIDS: have a definite shape and volume. ii. LIQUIDS: have definite volume, but their shape conforms to the container iii. GASES: have no definite shape or volume b. MATTER can undergo PHYSICAL & CHEMICAL CHANGES i. PHYSICAL CHANGES: do not alter the basic nature of the substance 1. EX: changes in states of matter or cutting food ii. CHEMICAL CHANGES: do alter the composition of the substance 1. EX: digesting food 2. ENERGY: the ability to do work or to put matter into motion a. There are two types of energy: i. POTENTIAL ENERGY: when energy is inactive and stored ii. KINETIC ENERGY: the ability to do work or to put matter into motion 3. *Matter is the substance & energy is the mover of the substance 4. Forms of Energy: a. CHEMICAL ENERGY: Is stored in the bonds of chemical substances. When these bonds are broken, stored (potential) energy is unleashed and becomes kinetic energy b. ELECTRICAL ENERGY: results from the movement of charged particles c. MECHANICAL ENERGY: is directly involved in moving matter, such as your legs moving a bike pedal d. RADIANT ENERGY: Travels in waves i. Includes: 1. X-rays 2. Infrared 3. Visible light 4. Radio 5. Ultraviolet 5. Energy Form Conversions a. Generally energy is easily converted from one form to another b. Energy conversions are not very efficient i. Some of the initial energy supply is “lost” or unusable, and produces heat Composition of Matter (27-32) 1. Elements and Atoms All Matter is composed of elements Elements are unique substances that cannot be broken down into simpler substances by ordinary chemical methods Examples: oxygen, carbon, gold, copper, and iron Carbon, oxygen, hydrogen and nitrogen make up 96% of body weight All elements are shown on the periodic table Atoms are the building blocks of elements Each element is designated by the atomic symbol 2. Atomic Structure The word atom comes from the Greek “incapable of being divided” The subatomic particles of atoms: Protons (p+) have a positive charge, neutrons (n0) have no charge, electrons (e-) have a negative charge equal to the strength of the positive charge in protons (+ to + or – to –) repel each other (+ to – ) attract Neutral particles are neither attracted nor repelled 3. Planetary and Orbital Models of an Atom The planetary model of an atoms portrays the atom as a miniature solar system in which the protons and neutrons are clustered at the center of the atom in the atomic nucleus The orbital model is a more modern model of atomic structure that has proved to be more useful in predicting the chemical behavior or atoms Electron clouds are depicted in the orbital model as located outside the nucleus 4. Identifying Elements There are 2 ways to identify elements: atomic number and atomic mass number Every element is given a number (atomic number) that is equal to the number of protons the atoms contain The atomic mass number of any atom is the sum of the protons and neutrons in the nucleus Atomic Weight: atoms of almost all elements exhibit two or more structural variations Isotopes have the same number of protons and electrons but vary in the number of neutrons they contain Heavier isotopes of certain atoms are unstable and tend to decompose to be more stable, these are called radioisotopes The process of spontaneous radioactive decay is called radio activity and can be compared to a tiny explosion Molecule and Compounds Molecules: when two or more atoms combine chemically Two or more atoms of the same element bond, a molecule is produced Compound: when two or more different properties form the atoms that make them up Atom is the smallest part of an element that still retains that element’s properties. Molecules are the smallest particle of a compound that still retains the properties of that compound When you break the bonds between the atoms of a compound, properties of the atom will be exhibted Chemical Bonds and Chemical Reactions: (pg. 33-39) Chemical reactions- occur whenever atoms combine with or dissociate with other atoms. 1) Bond Formation A) Role of electrons: i) Electron Shells/Energy Levels- the fixed regions of space around the nucleus that electrons occupy ii) Valence Shell- the atom’s outermost shell; its electrons determine the chemical behavior of the atom B) Chemically inert and reactive elements: i) Chemically Inert- when the outermost valence shell, energy level, is fully occupied by electrons ii) Chemically Reactive- when the valence shell, energy level, of an element is incomplete C) Types of chemical bonds: Ionic Bonds: form when electrons are completely transferred from one atom to another Ions- the charged particle that occurs when a neutrally charged atom gains or loses electrons during bonding, their positive and negative charges are no longer balanced Salts- most elements formed by Ionic Bonding fall into this general category of chemicals, ex- Sodium Chloride i) Covalent Bonds: the bonds of covalent molecules Covalent molecules- atoms that share electrons Nonpolar covalently bonded molecules- when covalent molecules’ electrons are shared equally between the atoms of the molecule Polar molecule- a molecule with two different charged poles ii) Hydrogen Bonds: extremely weak bonds formed when hydrogen atoms bound to one electron-hungry nitrogen or oxygen atom is attracted by another electron-hungry atom, and the hydrogen forms a “bridge” between them. (1) Intramolecular bonds- bonds that help bind different parts of the same molecule together into a 3-deminsional shape (hydrogen bonds are important Intramolecular bonds) 2) Patterns of Chemical Reactions A) Synthesis Reactions: occur when two or more atoms or molecules combine to form a larger, more complex molecule, ex. A + B AB B) Decomposition Reaction: occur when a molecule is broken down into smaller molecules, ex. AB A + B C) Exchange Reactions: involves both Synthesis and Decomposition, molecules or both built up and broke down, ex. AB + C AC + B and AB + CD AC +BD Organic Compounds • A compound containing carbon. - ex. 1. Carbohydrates 2. Proteins 3. Fats • Carbohydrates • Carbs include sugars and starches - these contain 1.Carbon 2.Hydrogen 3.Oxygen • Carbohydrate means “hydrated carbon” • Carbs are classified by size - these sizes include 1.Monosaccharides 2.Disaccharides 3.Polysaccharides -monosaccharides are the “building block” of carboydrates • Carbs continued…. • Monosaccharides, or simple sugars, are vital for body function - glucose is a monosaccharide and is the universal cellular fluid • Disaccharides, or double sugars, are formed by a process called dehydration synthesis - ex. 1.Sucrose (found in sugar cane) 2.Lactose (found in milk) 3.Maltose (malt sugar) - these double sugars are broken down by the body to simple sugars (glucose) • Carbs continued… • Polysaccharides, or many sugars are branching chains of linked simple sugars. - ex. Starches and Glycogen - these lack the sweetness of the other two sugars because of their size