Chemistry Review

Cards (33)

  • Element: A substance that cannot be broken down into other kinds of substances by ordinary chemical means
  • Atom: The smallest unit of an element that retains all of the element’s properties
  • Proton: mass = about 1 unit, electric charge = +1 unit
  • Neutron: mass = about 1 unit, electric charge = 0
  • Electron: mass = about 0 units, electric charge = -1 unit
  • The number of protons in an atom determines the element
  • Isotopes: Atoms with the same number of protons (the same element), but different numbers of neutrons
  • Valence Shell: The outermost shell that contains one or more electrons
  • Covalent Bond: A chemical bond in which two atoms share one pair of valence electrons
  • Molecule: Two or more atoms held together by chemical bonding
  • Compound: Molecules with two or more elements
  • Emergent Properties: The properties of a compound are not simply a combination of the properties of its elements
  • Polar Molecule: A molecule with an uneven distribution of electric charge
  • Hydrogen Bond: Weak attraction between polar molecules
  • Ion: Atom (or molecule) with a net electric charge
  • Ionic Bond: A chemical bond resulting from the attraction between oppositely charged ions
  • Crystal: A regular three-dimensional lattice of atoms
  • Homogeneous Mixture/Solution: Components cannot be distinguished with a light microscope
  • Heterogeneous Mixture: Components can be distinguished visually
  • Chemical Reaction: The making and breaking of chemical bonds
  • Enzyme: Makes a chemical reaction take place more easily (a catalyst)
  • Molecules always have kinetic energy, they are moving
  • Temperature is just a measure of the average kinetic energy of molecules
  • Diffusion: The net movement of a substance from an area of high concentration to an area of low concentration
  • Osmosis: The diffusion of water across a semi-permeable membrane
  • Four Classes of Biologically Important Macromolecules:
    • Lipids (e.g., fat, oil, wax): non-polar, high in chemical energy
    • Carbohydrates (e.g., sugars, starch, cellulose): polar, high in chemical energy
    • Nucleic Acids (e.g., DNA, RNA)
    • Proteins (e.g., enzymes, hormones, structural proteins)
  • Monosaccharides: single sugar unit (e.g., glucose, fructose, galactose)
    • Disaccharides: two sugar units (e.g., sucrose, lactose, maltose)
    • Polysaccharides: many sugar units (e.g., starch, cellulose, glycogen)
  • Proteins:
    • Folded chain of amino acids (unfolded: polypeptide)
    • Some parts polar, other parts non-polar
    • Primary structure: the sequence of amino acids
    • Secondary structure: repeated coils or folds of the primary structure
    • Tertiary structure: irregular folding of the primary and secondary structure
    • Quaternary structure (not always present): two or more tertiary structures integrated into a functional unit
    • Hydrophobic (water fearing) vs. hydrophilic (water loving)
  • What is acidity?
    The concentration of hydrogen ions.
  • What is acid?
    A substance that in water increases the concentration of hydrogen ions.
  • What is a base?
    A substance that in water increases the concentration of hydroxide ions.
  • Acidity of Water:
    • high pH = low concentration of hydrogen ions
    • low pH = high concentration of hydrogen ions
  • What is the movement of a substance from a high concentration to a low concentration?
    Diffusion