Chemistry unit 2

• Empirical formula


  A formula which shows the simplest whole number ratio of atoms of each element in a compound
• Molecular formula


  A formula which shows the actual number of atoms of each element in a molecule
• Molar gas volume


  The volume of one mole of gas under specified conditions of temperature and pressure e.g. 24 dm' at 20 °C (293K) and one atmosphere pressure
• Percentage yield


  actual yield / theoretical yield x 100
• Atom economy


  mass of desired product / total mass of products x 100
• Homologous series


  Compounds which have the same general formula, similar chemical properties, show a gradation in physical properties and successive members differ by a CH₂ unit
• Functional group


  Reactive group within a compound
• Structural isomers


  Molecules which have the same molecular formula but a different structural formula
• Geometric isomers


  Molecules with the same structural formula, but different arrangement of atoms due to the presence of one or more C=C bond
• Saturated hydrocarbon


  Contains no C=C or CEC bond
• Hydrocarbon


  Contains hydrogen and carbon only
• Substitution


  Replacing one atom or group with a different atom or group
• Homolytic fission


  Bond breaking in which one of the shared electrons goes to each atom
• Heterolytic fission


  Bond breaking in which both electrons in the shared pair go to a single atom
• Radical


  A particle with an unpaired electron
• Unsaturated hydrocarbon


  Contains at least one C=C or C=C bond
• Sigma bond


  A covalent bond formed by the linear overlap of atomic orbitals
• Pi bond


  A covalent bond formed by the sideways overlap of p orbitals
• Bond length


  The distance between the nuclei of two covalently bonded atoms
• Homogeneous (equilibria)


  A reaction in which all the reactants and products are in the same physical state
• Heterogeneous (equilibria)


  A reaction in which all the reactants and products are not in the same physical state
• Kc


  [C][D]d / [A] [B]b
• Heterogeneous (catalyst)


  The catalyst is in a different phase from the reactants
• 1. block element


  An element which has an atom with highest energy/outer electron in an s-subshell (orbital)
• Solubility


  The maximum mass of solute that will dissolve in 100 g of solvent at a stated temperature