chap 2 - flashcards - mader bio.txt

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chap 2 - flashcards - mader bio.txt
2010-09-18 10:42:27

Bio Chap 2 - Basic Chemistry
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  1. Acid
    Molecules tending to raise the hydrogen ion concentration in a solution and to lower its pH numerically.
  2. Atom
    Smallest particle of an element that displays the properties of the element.
  3. atomic mass
    Average of atom mass units for all the isotopes of an atom.
  4. atomic number
    Number of protons within the nucleus of an atom.
  5. atomic symbol
    One or two letters that represent the name of an element�e.g.- H stands for a hydrogen atom- and Na stands for a sodium atom.
  6. Base
    Molecules tending to lower the hydrogen ion concentration in a solution and raise the pH numerically.
  7. Buffer
    Substance or group of substances that tend to resist pH changes of a solution- thus stabilizing its relative acidity and basicity.
  8. Calorie
    Amount of heat energy required to raise the temperature of one gram of water 1�C.
  9. Compound
    Substance having two or more different elements united chemically in fixed ratio.
  10. covalent bond
    Chemical bond in which atoms share one pair of electrons.
  11. Electron
    Negative subatomic particle- moving about in an energy level around the nucleus of an atom.
  12. electron shell
    Concentric energy levels in which electrons orbit.
  13. Electronegativity
    The ability of an atom to attract electrons toward itself in a chemical bond.
  14. Element
    Substance that cannot be broken down into substances with different properties; composed of only one type atom.
  15. Evaporate
    Conversion of a liquid or a solid into a gas.
  16. Formula
    A group of symbols and numbers used to express the composition of a compound.
  17. hydrogen bond
    Weak bond that arises between a slightly positive hydrogen atom of one molecule and a slightly negative atom of another molecule or between parts of the same molecule.
  18. hydrogen ion (H_)
    Hydrogen atom that has lost its electron and therefore bears a positive charge.
  19. Hydrophilic
    Type of molecule that interacts with water by dissolving in water and/or by forming hydrogen bonds with water molecules.
  20. Hydrophobic
    Type of molecule that does not interact with water because it is nonpolar.
  21. hydroxide ion (OH_)
    One of two ions that results when a water molecule dissociates; it has gained an electron and therefore bears a negative charge.
  22. Ion
    Charged particle that carries a negative or positive charge.
  23. ionic bond
    Chemical bond in which ions are attracted to one another by opposite charges.
  24. Isotope
    Atom of the same element having the same atomic number but a different mass number due to the number of neutrons.
  25. mass number
    Mass of an atom equal to the number of protons plus the number of neutrons within the nucleus.
  26. Matter
    Anything that takes up space and has mass.
  27. Molecule
    Union of two or more atoms of the same element; also- the smallest part of a compound that retains the properties of the compound.
  28. Neutron
    Neutral subatomic particle- located in the nucleus and assigned one atomic mass unit.
  29. nonpolar covalent bond
    Bond in which the sharing of electrons between atoms is fairly equal.
  30. octet rule
    The observation that an atom is most stable when its outer shell is complete and contains eight electrons; an exception is hydrogen which requires only two electrons in its outer shell to have a completed shell.
  31. pH scale
    Measurement scale for hydrogen ion concentration.
  32. polar covalent bond
    Bond in which the sharing of electrons between atoms is unequal.
  33. Proton
    Positive subatomic particle located in the nucleus and assigned one atomic mass unit.
  34. Salt
    Ionic compound that results from a classical acid-base reaction.
  35. Solute
    Substance that is dissolved in a solvent- forming a solution.
  36. Solution
    Fluid (the solvent) that contains a dissolved solid (the solute).
  37. surface tension
    Force that holds moist membranes together due to the attraction of water molecules.
  38. Tracer
    Substance having an attached radioactive isotope that allows a researcher to track its whereabouts in a biological system.
  39. valence shell
    Outer shell of an atom.