BIOL 189 Exam 1 Chemistry

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BIOL 189 Exam 1 Chemistry
2015-02-10 11:37:31
biol189 exam1
nevada state college
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  1. What is matter?
    • Anything that has
    • space and has mass (anything that occupies space)
  2. What is an element?
    • A substance which
    • cannot be broken down into other substances by chemical reaction (gold, carbon,
    • etc).
  3. What are the four elements that make up more than 96% of the elements in living things?


    C: Carbon

    H: Hydrogen

    O: Oxygen

    N: Nitrogen
  4. What is trace element?
    • A chemical
    • element present only in minute amounts in a particular sample or environment.


    • (Boron [B],
    • Chromium [Cr], Cobalt [Co], Copper [Cu], Fluorine [Fl], Iodine [I], Iron [Fe],
    • Manganese [Mn], Molybdenum [Mo], Selenium [Se], Silicon [Si], Tin [Sn],
    • Vanadium [V], Zinc [Zn].
  5. Make up of Atom:
    • Proton: proton is positively charged
    • inside the nucleus


    • Neutron: neutron is not charged,
    • located inside the nucleus


    • Electron: electrons are negatively
    • charged, located outside the nucleus
  6. What does the
    number of protons tell us about an atom?
    • The atomic number is the number
    • of protons in an atom of
    • an element.
  7. What does the
    number of neutrons tell us about an atom? (isotopes)
    • Protons + neutrons = mass #, so if more neutrons are
    • present, it can become and isotope
  8. What are
    radioisotopes, and what are they doing?
    • Unstable isotopes are called radioisotopes, they give
    • off radioactivity (unstable nuclei decay into different elements by emitting
    • subatomic particles and gamma rays) 
    • Unstable isotopes will lose protons, other subatomic particles, or energy
    • to form a more stable element
  9. What does the
    number of electrons tell us about an atom?
    • -Whether or not the atom has a vacancy
    • to form bonds

    • -Configuration of electrons determine
    • the chemical properties of an element (interactions)

    • -Electrons move near the speed of
    • light

    • -Electrons with higher energy can
    • sustain a larger orbit around the nucleus

    • -Only certain energy levels are found
    • in atoms; these define the electron shells
  10. What are ionic
    and covalent bonds? Which bond is strongest?
    • Ionic bonds- a bond between ions-when
    • a positive and negative elements bond

    • Ion-charges atom or molecule due to
    • loss or gain of an electron



    • Atoms SHARE electrons to form a
    • molecule


    • The strongest bond is Covalent Bonds,
    • because it shares an electron between two elements.
  11. What is a
    Two or more atoms attached by covalent bonds
  12. What is chemical
    Two or more elements in a fixed ratio
  13. What are
    hydrogen bonds?
    • Weak bonds associated with attraction
    • among polar molecules

    • (Polar molecules have unequal
    • distribution of charge around their peremeter)

    • Slightly positive, and slightly negative
    • charges of polar covalent molecules
  14. What is a
    molecules polarity based on?
    The amount of protons and electrons
  15. How do the
    properties of water favor life?
    • Water has properties that favor life
    • due to its polarity and hydrogen bonding

    Stabilizes temp

    Excellent solvent

  16. How does the pH
    scale work, and why is it important in cells?
    • The pH scale
    • measures the amount of hydrogen ions in a substance


    pH: potential hydrogen

    • Acid: donates H+ ions to solution
    • (pH<7)

    • Base: accepts H+ ions from solution
    • (pH>7)


    pH scale ranges from 0-14

    • Each step indicates of 10 folds. Water has a pH of 7,
    • because it accepts as many H+ as it donates.
  17. Essay question: Explain how
    electrons enable different types of bonds to form. Discuss covalent, ionic, and
    hydrogen bonds.