Bio Unit 2 - Inorganic Chemistry

Organization of Life

List from smallest to largest

  1. Atom - Smallest Particle of an Element

    1. Atomos - invisible

  2. Molecule

  3. Macromolecule

  4. Organelle

  5. Cell

  6. Tissue

  7. Organ

  8. Organ System

  9. Organism

Matter - Anything that occupies Space and has Mass

  • the entire universe

  • made up of:

    • Atoms

    • Elements

    • Compounds

Parts of an Atom

  • Electrons - Negatively charged particles found traveling Around the Nucleus in Various Energy Levels

  • Nucleus - Middle of the atom made up of Protons and Neutrons

    • Protons - Positively charged particles

    • Neutrons - Neutrally charged particles

Elements

  • Pure Substances made up of only 1 type of Atom

  • The periodic table - an arrangement of elements based on a set of properties

    • Atomic Number - # of Protons (Electrons) in Neutral Atoms

    • Atomic Mass - Weighted Average of All Isotopes for an Element

    • Mass Number - Number of Protons + Number of Neutrons

    • Element Name (ex. Carbon)

    • Element Symbol (ex. C)

Isotopes

  • Atoms of the Same Element that have a Different Number of Neutrons

    • Same number of Protons (Atomic Number)

  • Neutral Atoms have an Equal Number of Protons and Neutrons

    • not all atoms are neutral


Radiometric Dating

  • Calculates the Age of an object based upon the Half Life of Radioactive Isotope

  • Half-Life = # of Years for Half the atoms to Decay

Valence Electrons

  • Electrons in an atom’s Outermost Orbital

  • # of Protons = # of Electrons (in a Neturally charged atom)

  • Electrons exist in Orbitals that Surround the Nucleus

  • Columns on the Periodic Table are based on the # of Valence Electrons

Compounds

Compound - Substance that is made from 2+ Similar Substances and Can be Broken Down into the Original Substances through Chemical Reactions

  • Elements are in a Fixed Porportion

    • ex. H2O, CO2

Chemical Bonds

  • Compounds are created by atoms Bonding together

  • Most bonds involve Valence Electrons

    • Octet Rule - Atoms look for bonding partners that will allow them to have 8 Valence Electrons

      • more stable

  • Ionic Bonds

    • Formed when one atom’s electron(s) are Transferred to another atom

    • When an atom Gains or Loses Electrons

    • # of Protons ≠ # of Electrons

    • Ionic Compounds = combined Ions

      • Ions are Positively OR Negatively charged atoms

      • Caions - Positive ions (lose electrons)

      • Anions - Negative ions (gain electrons)

      • Oppositely charged ions have strong Attraction for each other

  • Covalent Bonds

    • Formed when 2+ electrons are Shared between the Nuclei of 2+ atoms

    • Intramolecular Forces - the Forces created from Sharing Electrons

      • Holds covalently-bonded molecules together

      • Intra = within

  • Polar Covalent Bonds

    • Covalent bond where electrons are Not shared equally between atoms

      • Leads to 2 Poles Forming

      • ex. Electrons are Not equally shared in H2O

        • Oxygen is More Electronegative than Hydrogen

          • Oxygen takes a slight Negative Charge

          • Hydrogen takes a slight Positive Charge

    • Electronegative - Tendency for an atom to Attract electrons to Itself

  • Hydrogen Bonds

    • Weak bond that forms between the Slight Positive Pole of one molecule and the Slight Negative Pole of another molecule

    • Water and other Polar Covalently bonded molecules can create hydrogen bonds with each other

    • Intermolecular Force - force that exists between 2 Molecules

      • Inter = “between”/”among”

Acids and Bases

  • Occasionally, the Hydrogen Bonds between Water Molecules are Strong Enough to Rip Hydrogens Off

  • About 1 in every 10 million molecules

  • Pure Water is Neutral

    • Equal Number of Positive and Negative Ions

Acids - substances that Release More hydrogen ions (H+) than hydroxide ions (OH-) in solution

  • pH Less Than 7

  • Lower the number, stronger the Acid

Bases - substances the Release More hydroxide ions (OH-) than hydrogen ions (H+) in solution

  • pH Greater Than 7

  • Higher the number, stronger the Base

pH - power of Hydrogen (as in Hydrogen Ions)

  • Measures the H+ concentration in solution

  • Log Scale - increases by Powers of 10

    • ex. pH2 = 100x more acidic than pH 4

    • 0- 14

    • Acidic - Neutral (7) - Basic (Alkaline)

Buffers - Solution that Prevents Sharp and Sudden Changes in pH

  • many animals have buffers in their Blood that Maintain a Constant pH

  • Ocean water acts as a buffer and Resists Changes in pH for marine organisms

  • Maintain Homeostasis of pH

    • otherwise Proteins Change Shape and Stop Working

Water

  • Human bodies are 60% water

    5 Properties of Water:

Cohesion:

  • Act of Molecules of the Same Substance Sticking Together

  • ex. 2 water molecules make hydrogen bonds

  • Causes High Surface Tension Strength

    • Difficult to break through

  • water = Viscous - difficult to Move Through

Adhesion

  • Act of Molecules of Different Substances Sticking Together

    • ex. water molecules sticking to glass

Capillary Action - Water’s Ability to Travel in Narrow Spaces Against the force of Gravity

  • Adhesion, Cohesion and Surface Tension working together

  • ex, water moving up the stem, water moving through a sponge, groundwater travels through soil

Universal Solvent

  • Water can Mix with Other Polar Molecules

    • Polar Molecules - Hydrophilic - “water-loving”

      • ex. water, ethanol, ammonia

    • Nonpolar Molecules - Hydrophobic = “water-hating”

      • ex. plant oils, carbon dioxide, benzene

    • Hydrophilic/Polar and Hydrophobic/Nonpolar molecules do Not mix together

  • Water can Dissolve Any Ionic Substances

    • Solute - substance being Dissolved

    • Solvent - substance Doing the dissolving

  • Water is the Universal Solvent

Heat Capacity

  • the Amount of Heat Needed to Raise the Temperature of the substance

  • Water has the Highest heat capacity of any Natural Substance

  • Heat energy must

    • 1. First be used to Break the Hydrogen Bonds

    • 2. Before the molecules can Move Faster and Increase Temperature

  • Water Protects organisms from Drastic changes in Temperature

    • Maintain Homeostasis

Less Dense as a Solid

  • 3 States of Water

    • Gas

    • Liquid

    • Solid

  • Water Vapor (Gas)

    • Occurs when water molecules have Enough Energy to Break Free from Hydrogen Bonds

    • Water molecules Spread Further Apart

    • Increasing Temperature = Increasing Evaporation

  • Liquid Water

    • Hydrogen bonds Hold water molecules Together, But they Can still Slip Past each other

    • Hydrogen Bonds are Constantly being Broken and Reformed As water molecules Move

    • Cold Water is More Dense because the molecules are moving Slower and are More Densely Packed

    • Warm Water is Less Dense because the molecules are moving Faster and Spread Out

  • Solid Water (Ice)

    • `Frozen water Locks water molecules into a Lattice Structure

    • Causes Ice to Expand

    • Ice Molecules are Further Apart Than Liquid

    • Therefore: Ice is less dense as a solid