69 terms

Chapter 2: Basic Chemistry of Physiology

The "stuff" of the universe, Anything that has mass and takes up space
States of matter: Solid
has definite shape and volume
States of matter: Liquid
has definite volume, changeable shape
States of matter: Gas
has changeable shape and volume
The capacity to do work (put matter into motion)
Types of energy: Kinetic
energy in action
Types of energy: Potential
energy of position; stored (inactive) energy
Forms of Energy: Chemical
stored in the bonds of chemical substances
Forms of Energy: Electrical
results from the movement of charged particles
Forms of Energy: Mechanical
directly involved in moving matter
Forms of Energy: Radiant or electromagnetic
energy traveling in waves (i.e., visible light, ultraviolet light, and X rays)
Composition of Matter: Elements
unique substances that cannot be broken down by ordinary chemical means
Composition of Matter: Atoms
more-or-less identical building blocks for each element
Composition of Matter: Atomic symbol
one- or two-letter chemical shorthand for each element
Major Elements of the Human Body
Oxygen (O) Carbon (C) Hydrogen (H) Nitrogen (N)
Lesser and Trace Elements of the Human Body
Lesser elements make up 3.9% of the body and include: Calcium (Ca), phosphorus (P), potassium (K), sulfur (S), sodium (Na), chlorine (Cl), magnesium (Mg), iodine (I), and iron (Fe) - Trace elements make up less than 0.01% of the body, They are required in minute amounts, and are found as part of enzymes
Atomic Structure: nucleus
The nucleus consists of neutrons and protons
Atomic Structure: Neutrons
have no charge and a mass of one atomic mass unit (amu)
Atomic Structure: Protons
have a positive charge and a mass of 1 amu
Atomic Structure: Electrons
Electrons are found orbiting the nucleus, They have a negative charge and 1/2000 the mass of a proton (0 amu)
Models of the Atom: Planetary Model
electrons move around the nucleus in fixed, circular orbits
Models of the Atom: Orbital Model
regions around the nucleus in which electrons are most likely to be found
Atomic number
equal to the number of protons
Mass number
equal to the mass of the protons and neutrons
Atomic weight
average of the mass numbers of all isotopes
atoms with same number of protons but a different number of neutrons
atoms that undergo spontaneous decay called radioactivity
two or more atoms held together by chemical bonds
two or more different kinds of atoms chemically bonded together
two or more components physically intermixed (not chemically bonded)
homogeneous mixtures of components
substance present in greatest amount
substance(s) present in smaller amounts
Colloids, or Emulsions
heterogeneous mixtures whose solutes do not settle out
heterogeneous mixtures with visible solutes that tend to settle out
Mixtures Compared with Compounds: Mixtures
No chemical bonding takes place in mixtures, Most mixtures can be separated by physical means, Mixtures can be heterogeneous or homogeneous
Mixtures Compared with Compounds: Compounds
Compounds cannot be separated by physical means, All compounds are homogeneous
Chemical Bonds
Electron shells, or energy levels, surround the nucleus of an atom, Bonds are formed using the electrons in the outermost energy level
Valence shell
outermost energy level containing chemically active electrons
Octet rule
atoms react in a manner to have 8 electrons in their valence shell
Inert elements
have their outermost energy level fully occupied by electrons
Reactive elements
do not have their outermost energy level fully occupied by electrons
Types of Chemical Bonds
Ionic, Covalent, Hydrogen
Ionic Bonds
Ions are charged atoms resulting from the gain or loss of electrons, Anions have gained one or more electrons, Cations have lost one or more electrons, Opposite charges on anions and cations hold them close together, forming ionic bonds
Formation of an Ionic bond
Ionic compounds form crystals instead of individual molecules, Example: NaCl (sodium chloride)
Covalent Bonds
Electrons are shared by two atoms, Electron sharing produces molecules
Hydrogen Bonds
Too weak to bind atoms together, Common in dipoles such as water, Responsible for surface tension in water, Important as intramolecular bonds, giving the molecule a three-dimensional shape
Chemical Reactions
Occur when chemical bonds are formed, rearranged, or broken
Patterns of Chemical Reactions: Combination reactions:
Synthesis reactions which always involve bond formation, A + B r AB
Patterns of Chemical Reactions: Decomposition reactions
Molecules are broken down into smaller molecules, AB r A + B
Patterns of Chemical Reactions: Exchange reactions
Bonds are both made and broken, AB + C 6 AC + B
Patterns of Chemical Reactions: Oxidation-Reduction (Redox) Reactions
Reactants losing electrons are electron donors and are oxidized, Reactants taking up electrons are electron acceptors and become reduced
Exergonic reactions
reactions that release energy
Endergonic reactions
reactions whose products contain more potential energy than did its reactants
Rate of Chemical Reactions: Temperature
chemical reactions proceed quicker at higher temperatures
Rate of Chemical Reactions: Particle size
the smaller the particle the faster the chemical reaction
Rate of Chemical Reactions: Concentration
higher reacting particle concentrations produce faster reactions
Rate of Chemical Reactions: Catalysts
increase the rate of a reaction without being chemically changed
Rate of Chemical Reactions: Enzymes
biological catalysts
Water: High heat capacity
absorbs and releases large amounts of heat before changing temperature
Water: High heat of vaporization
changing from a liquid to a gas requires large amounts of heat
Water: Polar solving properties
dissolves ionic substances, forms hydration layers around large charged molecules, and serves as the body's major transport medium
Water: Reactivity
is an important part of hydrolysis and dehydration synthesis reactions
Water: Cushioning
resilient cushion around certain body organs
Acidic Solutions:
Higher H+ concentration and therefore a lower pH - pH 0-6.99
Alkaline Solutions
Lower H+ concentration and therefore a higher pH - pH 7.01-14
Neutral Solutions
Equal H+ and OH- concentrations - pH 7.00
Systems that resist abrupt and large swings in the pH of body fluids
Buffers: Carbonic acid
bicarbonate system- Carbonic acid dissociates reversibly releasing bicarbonate ions and protons, The chemical equilibrium between carbonic acid and bicarbonate resists pH changes in the blood