Chemistry Lab

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Chemistry Lab

• Division C

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• Andy Shaw
• Sr. Research Biochemist
• Merck Co.
• West Point, PA
• Ph.D. in Chemistry
• University of Illinois

• 7 years involvement with Science Olympiad
• 5 years State Event Supervisor
• 3 years Regional Event Supervisor
• 2005 National Event Supervisor
• 2006 Coaches Clinic Presenter

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Chemistry Lab Basics

• Two-Person Event
• It is recommended, but not required, that teams
  include one student who has already completed one
  year of chemistry
• Two-Part Event
• Chemistry Lab is typically split into two main
  topics
• Each topic may be divided into multiple
  experiments or multiple observation stations
• Questions will cover both topics two tiebreakers
• Time Limit 50 Minutes
• Work AND cleanup must be completed in 50 minutes
• Depending on the setup, students may have the
  option to work individually on each part

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Rule Changes

• NONE
• (YEAH!!)

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Safety in the Laboratory

• Students must bring and wear at all times
• Aprons or lab coats
• OSHA approved splash goggles with indirect vents
• No open-toed shoes may be worn
• Pants or skirts must cover legs to ankles
• Gloves are recommended
• Students lacking the proper attire or protective
  equipment will not be allowed to compete!

• No tasting or touchingof powders is allowed
• Chemical waste must be disposed of in the waste
  containers provided
• No mouth pipetting
• Students who perform unsafe procedures will be
  disqualified from the event!

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Typical Penalties

• Incomplete Bench Cleanup
• At the end of 50 minutes, the work area must be
  cleaned and chemicals returned to their original
  location
• Safety Violations
• Goggles must be worn when handling chemicals
• Poor Laboratory Technique
• Significant Figures Errors
• Incorrect or Omitted Units

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Yearly Requirements

• Recording observations from one or more
  observation stations
• Interpretation of data, both graphical and
  tabular
• Stoichiometry mole conversions, percent yield
• Calculations using relevant equations
• Nomenclature and formula writing
• Elemental forms
• Derive symbols/charges for monatomic ions, such
  as Na, O2, and Br- from the periodic table
• Memorize symbols/charges for the polyatomic ions
  nitrate(-ite), carbonate, phosphate(-ite),
  acetate, sulfate(-ite), ammonium, bicarbonate,
  and hydroxide

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Yearly Changes

• Topics
• The two topics of focus change each year
• Experiments
• Accordingly, the experiments change along with
  the topics and vary in length and in design
• Questions and Equations
• The set of equations needed to answer questions
  varies with the topic students are expected to
  know relevant equations and the variables they
  contain
• Division of Labor
• Because of equipment limitations, students may
  have a decided amount of time to work on each
  experiment or observation station before moving
  on
• Depending on the setup, students may or may not
  be able to work individually on the different
  experiments

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Strategies for Success

• Read directions completely!
• Answer questions as directly as possible
• Balance equations when necessary
• Show work!
• Write down everything relevant to the question
  partial credit is sometimes given, and if nothing
  else, the equation usually provides a good
  starting point
• Work efficiently
• If a question is particularly difficult, move on
• Ask the proctors questions if confused
• Safety is the foremost concern! If there are
  procedural questions, it is better to ask than to
  be unsafe!

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Preparation - Teamwork

• Prepare together
• Teams will benefit from doing experiments
  together ahead of time
• Determine individual strengths
• Divide tasks during competition
• Check teammates work
• Teammates should check one another for time
  management purposes, too

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Preparation - Material

• Know the equations
• Know what variables represent
• Equations are sometimes given, but are useless
  without the units or values for the variables
• Look for the most common experiments, by topic,
  and do them
• Understand conversions (i.e. L ? mol, C ? J)

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2006 Chemistry Lab - Topics

• Thermodynamics
• Direction of heat flow, phase diagrams
• Endothermic vs. exothermic processes
• Heat capacity and calorimetry
• Heats of fusion, vaporization, and reaction
• Entropy, Gibbs free energy
• Physical Properties
• Elasticity and brittleness
• Conductivity and electrical resistance, magnetism
• Density
• Melting and boiling points
• Solubility

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2006 ChemLab - Equations
Thermodynamics n?Hdissolution -qsurr
-mC?Twhere n of moles, C 4.184 J/(mol
C) ?G ?H T?S ?G -RT ln(K) qsys
-qsurr n mass / formula weight error
(actual experimental) / actual 100
Physical Properties ? (density) m / V M
grams solute / L solvent Intermolecular forces
ion-ion gt ion-dipole gt H-bonding gt dipole-dipole
gt London Dispersion Forces
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2006 ChemLab - Experiments

• Thermodynamics
• Determine the specific heat of a metal or of a
  liquid
• Determine the heat of reaction (?Hrxn) coffee
  cup calorimetry
• Determine heat of fusion of ice
• Determine heat of combustion
• Apply Hess Law
• Determine heat exchange between water samples

• Physical Properties
• Determine the density of an object
• Use density to identify unknowns
• Use Hookes Law to determine the elasticity of a
  solid
• Separate a mixture by physical means
• Explore the relationship between solubility and
  temperature
• Explore the relationship between chemical
  structure and boiling or melting points

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2006 ChemLab - Questions

• Thermodynamics
• Sulfur trioxide decomposes to sulfur dioxide and
  oxygen gas.
• Write out and balance the decomposition reaction.
• 2SO3 ? 2SO2 O2
• Calculate ?Grxn given ?Gf for the above
  compounds
• ?Grxn 2?Gf(SO2) - 2 ?Gf(SO3)
• Are reactants or products favored at room
  temperature, 25C?
• ?G is positive - reactants
• At which temperature would the reaction favor the
  other?
• Calculate T from ?G ?H T?S, where ?G 0 T
  is in units of K

• Physical Properties
• Ethanol, water, and silicone oil are heated on a
  hot plate and receive the same amount of heat,
  but are at different temps.
• Given the structure of these compounds, a) why
  are they at different temperatures, b) what is
  the label for the x-axis above, including units,
  and c) to which liquids could A and B correspond?

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2007 Chemistry Lab

• Nuclear Chemistry
• Observation station with a Geiger counter to
  detect emissions
• Calculate half-lives for compounds, such as
  carbon-dating using 14C emission
• Differentiate between types of radiation (a, ß, ?
  particles) and effectiveness of radiation
  shielding
• Gas Laws
• Ideal gas law Understand the relationship
  between P, V, and T, and how changing one affects
  the others
• Determine the partial pressure of a wet gas, and
  predict its volume at a different temperature
• Calculate the densities and relative effusion
  rates of different gases

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2008 Chemistry Lab

• Chemical Reactions
• Investigate an activities series
• Investigate different types of reactions
• Investigate solubility rules
• Energy
• Determine specific heat, heat of vaporization or
  fusion
• Determine the amount of energy in a fuel
• Use Hesss Law
• Explore heating or cooling curves

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Tips from the Supervisor

• Read the instructions through first!!
• Students should to plan their time for an event
  by reading the experiments before they begin
• Divide and conquer know individual strengths
  and work separately to complete tasks if needed
• Have a good foundation in making physical
  measurements (mass, pH, etc.)

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Additional Resources

• Visit the Chemistry Lab webpage at the Science
  Olympiad website
• http//www.soinc.org/events/chemlab/index.htm
• Doesnt look like its been updated for this year
  yet, but keep checking back.