Ch 281 Chapter 2

  1. Acid
    Proton donor that releases H+ (and anions) when dissolved in water.
  2. Acidity
    The concentration of H+ in a water solution, as compared with the concentration of OH–.
  3. Adhension
    The adherence of molecules to the walls of conducting tubes, as in plants.
  4. anion
    A negatively charged ion.
  5. atom
    The smallest unit that retains the chemical and physical properties of an element.
  6. atomic nucleus
    The nucleus of an atom, containing protons and neutrons.
  7. atomic number
    The number of protons in the nucleus of an atom.
  8. atomic weight
    The weight of an element in grams, equal to the mass number.
  9. Avogadro's number
    The number 6.022 × 1023, derived by dividing the atomic weight of any element by the weight of an atom of that element.
  10. base
    Proton acceptor that reduces the H+ concentration of a solution.
  11. bilayer
    A membrane with two molecular layers.
  12. bioremediation
    Applications of chemical and biological knowledge to decontaminate polluted environments.
  13. buffer
    Substance that compensates for pH changes by absorbing or releasing H+.
  14. calorie (cal)
    The amount of heat required to raise 1 g of water by 1°C, known as a "small" calorie; when capitalized, a unit equal to 1,000 small calories.
  15. cation
    A positively charged ion.
  16. chemical bond
    Link formed when atoms of reactive elements combine into molecules.
  17. Chemical Equation
    A chemical reaction written in balanced form.
  18. cohesion
    The high resistance of water molecules to separation.
  19. compound
    A molecule whose component atoms are different.
  20. concentration
    The number of molecules or ions of a substance in a unit volume of space.
  21. covalent bond
    Bond formed by electron sharing between atoms.
  22. dalton
    A standard unit of mass, about 1.66 × 10–24 grams.
  23. dissociation
    The separation of water to produce hydrogen ions and hydroxide ions.
  24. electron
    Negatively charged particle outside the nucleus of an atom.
  25. electronegativity
    The measure of an atom's attraction for the electrons it shares in a chemical bond with another atom.
  26. element
    A pure substance that cannot be broken down into simpler substances by ordinary chemical or physical techniques.
  27. energy levels
    Regions of space within an atom where electrons are found. Also referred to as shells.
  28. formula
    The name of a molecule written in chemical shorthand.
  29. heat of vaporization
    The heat required to give water molecules enough energy of motion to break loose from liquid water and form a gas.
  30. hydration layer
    A surface coat of water molecules that covers other polar and charged molecules and ions.
  31. hydrogen bond
    Noncovalent bond formed by unequal electron sharing between hydrogen atoms and oxygen, nitrogen, or sulfur atoms.
  32. hydrophilic
    Polar molecules that associate readily with water.
  33. hydrophobic
    Nonpolar substances that are excluded by water and other polar molecules.
  34. ice lattice
    A rigid, crystalline structure formed when a water molecule in ice forms four hydrogen bonds with neighboring molecules.
  35. Ion
    A positively or negatively charged atom.
  36. ionic bond
    Bond that results from electrical attractions between atoms that have lost or gained electrons.
  37. isotope
    A distinct form of the atoms of an element, with the same number of protons but different number of neutrons.
  38. kilocalorie (kcal)
    The scientific unit equivalent to a Calorie and equal to 1,000 small calories.
  39. mass
    The amount of matter in an object.
  40. mass number
    The total number of protons and neutrons in the atomic nucleus.
  41. matter
    Anything that occupies space and has mass.
  42. molarity (M)
    The number of moles of a substance dissolved in 1 L of solution.
  43. mole (mol)
    Amount of substance that contains as many atoms or molecules as there are atoms in exactly 12 g of carbon-12, which is 6.022 × 1023.
  44. molecular weight
    The weight of a molecule in grams, equal to the total mass number of its atoms.
  45. molecule
    A unit composed of atoms combined chemically in fixed numbers and ratios.
  46. neutron
    Uncharged particle in the nucleus of an atom.
  47. nonpolar association
    Association that occurs when nonpolar molecules clump together.
  48. nonpolar covalent bond
    Bond in which electrons are shared equally.
  49. orbital
    The region of space where the electron "lives" most of the time.
  50. pH scale
    The numerical scale used by scientists to measure acidity.
  51. polar association
    Association that occurs when polar molecules attract and align themselves with other polar molecules and with charged ions and molecules.
  52. polar covalent bond
    Bond in which electrons are shared unequally.
  53. product
    An atom or molecule leaving a chemical reaction.
  54. proton
    Positively charged particle in the nucleus of an atom.
  55. radioactivity
    The giving off of particles of matter and energy by decaying nuclei.
  56. radioisotope
    An unstable, radioactive isotope.
  57. reactants
    The atoms or molecules entering a chemical reaction
  58. reversible
    The term indicating that a reaction may go from left to right or from right to left, depending on conditions.
  59. shells
    Regions of space within an atom where electrons are found.
  60. solute
    The molecules of a substance dissolved in water.
  61. solution
    Substance formed when molecules and ions separate and are suspended individually, surrounded by water molecules.
  62. solvent
    The water in a solution in which the hydration layer prevents polar molecules or ions from reassociating.
  63. specific heat
    The amount of heat required to increase the temperature of a given quantity of water.
  64. surface tension
    The force that places surface water molecules under tension, making them more resistant to separation than the underlying water molecules.
  65. trace element
    An element that occurs in organisms in very small quantities (< 0.01%); in nutrition, a mineral required by organisms only in small amounts.
  66. tracer
    Isotope used to label molecules so that they can be tracked as they pass through biochemical reactions.
  67. valence electron
    An electron in the outermost energy level of an atom.
  68. Van der Waals forces
    Weak molecular attractions over short distances.
  69. water lattice
    An arrangement formed when a water molecule in liquid water establishes an average of 3.4 hydrogen bonds with its neighbors.
  70. weight
    A measure of the pull of gravity on an object.
Card Set
Ch 281 Chapter 2
Ch 281 Chapter 2 vocab