Final Exam

• How do you convert mass to moles

  Multiply by a conversion factor
• what is the literal meaning of stiochiometry

  Element measure
• the four basic steps of stiochiometry

  1. balanced chemical equation
  2. convert to moles
  3. mole ratio
  4. convert from moles
• What’s a limiting reactant

  when you have two reactants, unless they are present in exactly the correct amount, one will run out first
• What is Theoretical Value

  Prediction of the amount of product from any amount of reactant
• What is Experimental Value

  When you do the actual procedure, most likely you will get a smaller number then the theoretical value
• What is Percent Value

  expression relating the theoretical and experimental value
• What does percent yield tell you

  What fraction of the whole you obtained
• What does Percent difference tell you

  how far off you were
• Solid phase


  Particles are close together in a fixed position
• Liquid Phase


  particles are close together, but not in a fixed position
• Gaseous Phase 


  particles are far apart, and not inn a fixed position
• Kinetic Molecular Theory

  1. Particles move quickly and randomly
  2. Fast moving particles = warm/ hot gases and vice versa
  3. Temperature is the average kinetic energy of all the particles )i.e. not all particles move at the same speed)
  4. Particles collide with no loss of energy
  5. When particles collide with the sides of their container, they exert a force pressure
• Boyle’s law 


  If you increase pressure, the volume decreased by the same measure
• Charles’ law

  volume and temperature were directly proportional
• Avogadro’s Hypothesis (Law of combining Gas volumes)

  The spaces between gaseous molecules is so vast that molecular size is irrelevant.

  Thus equal volumes of any two gases at the same temperature and pressure will contain the same number of moles of that gas
• What is a solution

  A homogenous mixture compromised of a solute and a solvent
• Solute 


  typically a solid that separates into individual, invisible components
• Solvent 


  Typically water; the solvent is what bonds with the solute particles and tears them into individual entities
• When a solute dissolves, there are two types of bonds involved

  • The bonds holding the solute particles together are being broken
  • New bonds between the solute and solvent are being formed
• Breaking bonds absorbs energy
• Making bonds releases energy
• endothermic 


  when heat is absorbed
• Exothermic 


  when heat is released
• Some solute-solute bonds are very hard to break. Those solutions will absorb more energy than they release when they dissolve

  They will feel cold
• Some solute-solute bonds are very easy to break. Those solutions will release more energy than they consume when they dissolve

  They will feel hot
• What does solubility mean

  the maximum amount of solute that can dissolve in a given solvent
• A solution that contains its maximum amount of solute is said to be saturated
• How do you get a supersaturated solution

  start with. solution, then you heat it until all the solid dissolves. If you let it cool slowly, the extra solute will not precipitate
• The solubility of solids generally increase with increasing temperature
• The solubility of gases generally decreases with increasing temperature
• You need moving electrons or moving ions to conduct electricity
• Ionic solutions conduct electricity

  Molecular solutions do not conduct electricity
• More ions = more conductivity
• Solid ionic compounds do not conduct electricity
• Molten Ionic compounds do conduct electricity
• What are electrolytes 


  Solutions that conduct electricity
• what are non-electrolytes 


  Solutions that do not conduct electricity
• grams and milliliters are equivalent units
• What is an entity

  an individual component that is present