BIO Chap 2 Self test

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BIO Chap 2 Self test
2012-02-16 13:36:12

Chapter 2 self test
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  1. The basic structural units of chemistry and life are __________.
  2. The atomic number of carbon is 6. A carbon atom has __________ protons and __________ electrons.
    6, 6
  3. Ions are atoms that have __________.
    gained or lost an electron
  4. Chemical bonds __________.
    • are the forces that hold atoms together in molecules
    • result when atoms share one or more electrons
    • are interactions between the outermost electron shells of atoms
    • result when atoms gain or lose one or more electrons
  5. Ionic bonds form between atoms that have __________.
    nearly empty and nearly full outermost electron shells
  6. Covalent bonds __________.
    • are interactions between the outermost electron shells of atoms
    • result when atoms share one or more electrons
    • are the forces that hold atoms together in molecules such as water
  7. Chemical reactions __________.
    • are interactions between the outermost electron shells of atoms
    • are the forces that hold atoms together in molecules
    • result when atoms share one or more electrons
    • result when atoms gain or lose one or more electrons
  8. How many single covalent bonds can the phosphorus atom form?
  9. Nonpolar covalent bonds are different from polar covalent bonds because __________.
    electrons are shared equally in nonpolar covalent bonds and are shared unequally in polar covalent bonds
  10. Why is water so essential for life?
    • Water is a good solvent.
    • Water takes part in many biochemical reactions.
    • Water moderates the effects of temperature.
    • The atoms in water molecules are held together in polar covalent bonds.
    • When water freezes, it forms ice that floats.
  11. Oxygen atoms have an atomic number of 8. Neon atoms
    have 10 electrons. Predict whether or not these atoms are generally reactive (i.e., can form chemical bonds with other atoms). Explain your answer. (Note that this question is not asking whether oxygen can react with neon.)
    Oxygen is reactive because its outermost electron shell contains electrons (is not filled); neon is not reactive because its outermost electron shell contains 8 electrons (is filled).
  12. Which of the following lists of terms is in the correct order of size, going from smallest to largest?
    electron, proton, atomic nucleus, electron shell, atom, molecule
  13. Why are hydrophobic molecules such as fats and oils unable to dissolve in watery solutions?
    Water molecules form hydrogen bonds with each other, excluding the hydrophobic molecules.
  14. You are waiting backstage for your cue to come onstage when you notice that you are breathing rapidly and beginning to feel light-headed. As you try to control your anxiety and slow your breathing, you think about what you learned in your biology class this week and realize that your hyperventilation is changing your blood pH. Explain. Reminder: Blood pH is maintained by carbonate buffer, which is related to the amount of CO2 you breathe in or out. One way that your body controls the amount of carbonate in your blood is to change the rate of breathing. When you breathe out, you remove CO2 and lower the amount of arbonic acid in the blood. As a result, the amount of H+ ions in the blood decreases. Take your time on this one; relating pH to changes in H+ concentration can be confusing.
    Rapid breathing increases the pH of my blood, making it more basic.
  15. Imagine that you wanted to make a time capsule in
    which you would seal important artifacts from your life (pictures,
    poems, a lock of your baby hair, etc.), to be opened by your heirs 1000
    years from now. To prevent these artifacts from decaying, you want to
    fill the capsule with a gas that would be least reactive. Which of these gases would you choose: oxygen gas (O2); carbon dioxide (CO2); argon gas (Ar); hydrogen gas (H2). (The atomic numbers of the atoms in these molecules are: oxygen = 8; carbon = 6; hydrogen = 2; and argon = 18.)
    argon gas
  16. Atoms are the basic building block of elements. Each atom, and therefore the elements themselves, are made up of subatomic bits of matter that are electrically negative (electrons), electrically positive (protons), and electrically neutral or uncharged (neutrons). Which subatomic component defines (characterizes) the fundamental nature of each element?
  17. What allows one atom to physically interact with a second atom?
    properties of the electrons
  18. One atom can form a chemical bond with a second atom as a result of __________.
    both atoms possessing incompletely filled outer electron shells
  19. Covalent bonds __________.
    all of the above
  20. Water's ability to act as a "universal" solvent is due to _________
    both the second and third answers above
  21. Why does water so greatly resist increases in temperature?
    It takes great energy to break the huge number of hydrogen bonds that hold water molecules togethe
  22. A solution of pH 7 has ________ times _________ H+ ions than a solution of pH 9.
    100; more
  23. Which of the following is not a subatomic particle?
  24. Which of the following best explains why neon (Ne) atoms would not form bonds with other atoms?
    The outer shells of neon atoms are completely full with eight electrons.
  25. The atoms Mg+ and Cl– would most likely be attached to each other by a(n) __________.
    ionic bond
  26. The atomic nucleus contains two types of subatomic particles; __________ are uncharged.
    protons neutrons
  27. Atoms of the same element with a different number of neutrons are called __________.
  28. The results of losing, gaining, or sharing electrons are __________.
    chemical bonds
  29. Atoms that have gained or lost electrons are called __________.
  30. Atoms with partially filled outermost electron shells
    can become stable by sharing electrons with another atom, forming a __________.
    covalent bond
  31. Ions and polar molecules are termed __________.
    hydrophillic hydrophobic
  32. Indicate which of the figures below depict neutral atoms and which depict ions.
    • A sodium atom (neutral)
    • B chlorine atom (neutral)
    • C sodium ion (+)
    • D chloride ion (–)
    • E sodium chloride (an ionic compound)
  33. Find the protons, neutrons, and electrons in this depiction of helium.
    • A proton
    • B neutron (no charge)
    • C electron (–)
  34. Identify the electrons, oxygen nucleus, hydrogen nucleus, and type of bond seen in the diagram below.

    • A electron
    • B hydrogen ion
    • C oxygen ion
    • D slightly positive end of molecule
    • E slightly negative end of molecule
  35. Hydrogen bonding is all based on a slight charge difference created when only 2 electrons circle the relatively larger nucleus of the hydrogen atom. Indicate on the figure below Which end of the water molecule will be positive and which will be negative. The red dashes indicate attractive forces.
    • A positive end of the water molecule
    • B negative end of the water molecule
  36. Below is the pH scale. Indicate which area is acidic, which is basic, and which is neutral.
    • A neutral pH
    • B basic end of the pH scale
    • C acidic end of the pH scale
  37. What is the purest form of matter that cannot be separated
    into different substances by chemical means?
  38. Which phrase best describes chemical bonds?
    attractive forces
  39. When an atom ionizes, what happens?
    It gives up or takes up one or more electrons.
  40. If electrons in water molecules were equally attracted to hydrogen nuclei and oxygen nuclei, water molecules would be
    less polar
  41. A covalent bond forms
    when two atoms share electrons
  42. What is the defining characteristic of an acid?
    It donates hydrogen ions.