What is Matter?
• Anything that has mass and occupies space
What are the 3 states of matter and their meanings?
1. Solid—definite shape and volume
2. Liquid—definite volume, changeable shape
3. Gas—changeable shape and volume
What is Energy?
• Capacity to do work or put matter into motion
What are the 2 types of energy?
• Kinetic—energy in action
• Potential—stored (inactive) energy
What are the 4 forms of energy?
• Chemical energy
• Electrical energy
• Mechanical energy
• Radiant or electromagnetic energy
What is Chemical Energy?
stored in bonds of chemical substances
What is Electrical Energy?
results from movement of charged particles
What is Mechanical Energy?
directly involved in moving matter
What is Radiant or electromagnetic energy?
exhibits wavelike properties (i.e., visible light, ultraviolet light, and X-rays)
1) What can be converted from one form to another?
2) What is inefficient?
2) • Conversion is inefficient because some energy is "lost" as heat
What are elements?
• Cannot be broken down by ordinary chemical means
What are Elements unique properties?
• Physical properties
Are detectable with our senses, or are measurable
• Chemical properties
How atoms interact (bond) with one another
What are Atoms?
Unique building blocks for each element
What are atomic symbols?
one- or two-letter chemical shorthand for each element
What are the major elements of the Human Body?
• Oxygen (O)
• Carbon (C)
• Hydrogen (H)
• Nitrogen (N)
What lesser elements of the human body takes about _%?
• Calcium (Ca), phosphorus (P), potassium (K), sulfur (S), sodium (Na), chlorine (Cl), magnesium (Mg), iodine (I), and iron (Fe)
What trace elements take __ of the human body?
• < 0.01% of body mass
• Part of enzymes, e.g., chromium (Cr), manganese (Mn), and zinc (Zn)
1) What determines atomic structure?
2) What does the nucleus consist of?
• Determined by numbers of subatomic particles
• Nucleus consists of neutrons and protons
What are Neutrons?
• No charge
• Mass = 1 atomic mass unit (amu)
What are Protons?
• Positive charge
• Mass = 1 amu
What are Electrons?
• Orbit nucleus
• Equal in number to protons in atom
• Negative charge
• 1/2000 the mass of a proton (0 amu)
1) What is the Orbital model?
2) What is it's purpose?
1) Current model used by chemists
• Depicts probable regions of greatest electron density (an electron cloud)
• Useful for predicting chemical behavior of atoms
1) What is the Planetary model and what is it's faults?
1) oversimplified, outdated model
2) Incorrectly depicts fixed circular electron paths
How can someone identify elements?
• Atoms of different elements contain different numbers of subatomic particles
What is the Atomic Number?
number of protons in nucleus
What is Mass Number?
mass of the protons and neutrons
• Mass numbers of atoms of an element are not all identical
What is an Isotope?
• Isotopes are structural variations of elements that differ in the number of neutrons they contain
What is atomic weight?
average of mass numbers of all isotopes
What is Radioisotopes and it's characteristics?
• Spontaneous decay (radioactivity)
• Similar chemistry to stable isotopes
• Can be detected with scanners
How is it useful in biological research and medicine?
• Cause damage to living tissue:
• Useful against localized cancers
• Radon from uranium decay causes lung cancer
What do atoms chemically combine to become?
molecules and compounds
What is an molecule?
two or more atoms bonded together (e.g., H2 or C6H12O6)
What is an compound?
two or more different kinds of atoms bonded together (e.g., C6H12O6)
What is a mixture?
• Two or more components physically intermixed
• Most matter exists as mixtures
What are 3 types of mixtures?
What is solution?
• Homogeneous mixtures
• Usually transparent, e.g., atmospheric air or seawater
What are 2 types of solutions?
Present in greatest amount, usually a liquid
Present in smaller amounts
How are solutions expressed?
• Percent, or parts per 100 parts
• Milligrams per deciliter (mg/dl)
• Molarity, or moles per liter (M)
What is 1 mole?
the atomic weight of an element or molecular weight (sum of atomic weights) of a compound in grams
What is Avogadro's number?
1 mole of any substance contains 6.02 X 10 to the 23 molecules (Avogadro's number)
What are Colloids?
• Heterogeneous translucent mixtures, e.g., cytosol
• Large solute particles that do not settle out
• Undergo sol-gel transformations
What is suspensions?
• Heterogeneous mixtures, e.g., blood
• Large visible solutes tend to settle out
What separates MIXTURE vs. Compounds?
• No chemical bonding between components
• Can be separated physically, such as by straining or filtering
• Heterogeneous or homogeneous
What separates mixture vs. COMPOUNDS?
• Can be separated only by breaking bonds
• All are homogeneous
How are Chemical Bounds used in Orbital Model?
• Electrons occupy up to seven electron shells (energy levels) around nucleus
• Octet rule: Except for the first shell which is full with two electrons, atoms interact in a manner to have eight electrons in their outermost energy level (valence shell)
What are Chemically Inert Elements?
• Stable and unreactive
• Outermost energy level fully occupied or contains eight electrons
What are Chemically Reactive Elements?
• Outermost energy level not fully occupied by electrons
• Tend to gain, lose, or share electrons (form bonds) with other atoms to achieve stability
What are 3 types of Chemical Bonds?
What are Ionic Bonds?
• Ions are formed by transfer of valence shell electrons between atoms
What are Anions?
• Anions (- charge) have gained one or more electrons
What are Cations?
• Cations (+ charge) have lost one or more electrons
What results in an Ionic bond?
• Attraction of opposite charges
How does an Ionic Bond form?
• Ionic compounds form crystals instead of individual molecules
What is a Covalent Bond?
• Formed by sharing of two or more valence shell electrons
• Allows each atom to fill its valence shell at least part of the time
How is a Covalent Bond's Sharing?
• Sharing of electrons may be equal or unequal
• Equal sharing produces electrically balanced nonpolar molecules
What is special about unequal sharing in Covalent Bonds?
• Unequal sharing by atoms with different electron-attracting abilities produces polar molecules
What is Electronegative?
• Atoms with six or seven valence shell electrons are electronegative, e.g., oxygen
What is Electropositive?
• Atoms with one or two valence shell electrons are electropositive, e.g., sodium
What is hydrogen bond?
What does it also act as?
• Attractive force between electropositive hydrogen of one molecule and an electronegative atom of another molecule
• Also act as intramolecular bonds, holding a large molecule in a three-dimensional shape
What are Chemical Reactions?
• Occur when chemical bonds are formed, rearranged, or broken
• Represented as chemical equations
What do Chemical Equations contain?
• Molecular formula for each reactant and product
• Relative amounts of reactants and products, which should balance
What are the 3 patterns of Chemical Reactions?
Synthesis (combination) reactions
• Decomposition reactions
• Exchange reactions
What is Synthesis Reactions?
• A + B --> AB
• Always involve bond formation
What is Decomposition Reactions?
• AB --> A + B
• Reverse synthesis reactions
• Involve breaking of bonds
What are Exchange Reactions?
• AB + C --> AC + B
• Also called displacement reactions
• Bonds are both made and broken
What are Oxidation-Reduction (Redox) Reactions?
• Decomposition reactions: Reactions in which fuel is broken down for energy
• Also called exchange reactions because electrons are exchanged or shared differently
Electron donors lose electrons and are oxidized
Electron acceptors receive electrons and become reduced
What is Exergonic Reactions?
And a example?
1) Release Energy
2) Catatonic reactions
What is Endergonic Reactions?
And a example?
products contain more potential energy than did reactants
• Anabolic reactions
1) What can all chemical reactions do theoretically?
2) When does Chemical equilibrium occur?
3) What biological reactions are irreversible due to?
1) • All chemical reactions are theoretically reversible
2) • Chemical equilibrium occurs if neither a forward nor reverse reaction is dominant
Energy requirements and Removal of products
How is rate of reaction influenced?
1) If temperature goes up
2) If particle size goes down
3) If concentration of reactant goes up
• If temperature goes up, rate goes up
• If particle size goes down, rate goes up
• If concentration of reactant goes up, rate goes up
1) What is catalyst?
2) What is an example of biological catalyst?
1) Rate goes up without being chemically changed