UNIT 6: Chemical Reactions

• Law of Conservation of Mass states that the mass can neither be created nor destroyed but is transformed from one form to another.
• Law of Definite Composition states when two elements combine to form a given compound, they always do so in fixed proportions.
• Law of Multiple Proportions states whenever the same two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.
• Chemical Reaction


  a substance is converted to one or more substances.
• Percent Composition


  the percent by mass of each element in a compound.
• Chemical Equations


  symbolic representations of chemical reactions
• Inhibitors


  slows down a chemical rxn
• catalyst


  speeds up a chem rxn
• What type of Chem Rxn is this?

  A + B -> AB

  Synthesis
• What type of Chem Rxn is this?

  AB -> A+B

  Decomposition
• What type of Chem Rxn is this?

  A + BC -> AB+C

  Single Replacement
• What type of Chem Rxn is this?

  AB + CD -> AD+CB

  Double Replacement
• Stoichiometry


  the determination of the proportions in which elements or compounds react with one another
• Limiting Reactant


  reactant that is all used up in a chem rxn.
• Actual yield


  amount obtained in the experiment
• Theoretical yield


  quantity calculated from the chem eq.
• What type of rxn is this:

  Hydrocarbon + O2 -> Heat and light + H2O + CO2

  Combustion
• Redox


  What type of rxn is this?

  
• Reduction


  gains e-, decrease in oxidation #s
• Oxidation


  loss of e-, increase in oxidation #s
• Mole Ratio


  Conversion factor between any two chem species in a chem rxn
• Lewis Acid


  accepts electron-pair to form a bond.
• Bronsted-Lowry Acid


  Proton (H+) donor
• Arrhenius Acid


  Dissociates into [H+] in a solution of water
• Lewis Base


  donates electron-pair to form a bond.
• Bronsted-Lowry Base


  Proton [H+] acceptor
• Arrhenius Base


  Dissociates into [OH-] in a solution of water
• pH level is 7.

  Neutral
• Neutralization


  a chemical reaction in which an acid and base quantitatively react together to form a salt and water as products
• pOH


  a scale used to determine the hydroxide ion (OH–) concentration in a solution.
• pH


  a scale used to determine the hydrogen ion (H+) concentration in a solution
• Indicators


  acid-base system in which weak acid (conjugate acid) has one acid & its conjugate base has another color.
• Buffer Solution


  has the ability to maintain almost constant pH using strong acid & base
• Titration


  process where there is progressive addition of a solution of known concentration to a known amt of an acid or base of unknown concentration.