ap chem

• Safety in the lab


  Wear safety goggles, never touch chemicals with fingers, add concentrated acid to water (not the other way around), neutralize acid spills with weak base (like baking soda), neutralize base spills with weak acid (like vinegar), do not neutralize with strong acid/base
• Ionic solution colors


  • Copper ion solutions are blue, iron ion solutions are yellow or orange, nickel ion solutions are green, cobalt ion solutions are pink, chromium ion solutions are yellowish or orange
• Volumetric pipette

  Used to dispense a very specific volume of liquid or solution, usually available in 1 mL, 5 mL, 10 mL, and 25 mL varieties
• Buret


  Used to measure precisely how much solution has been dispensed, usually in titrations
• Graduated cylinder


  Can be used to dispense a somewhat precise volume, accurate to within a couple of milliliters
• Beaker


  Used to contain a liquid or solution, not for precise measurement
• Florence flask


  Basically a storage container for a solution or distilled water, usually round with no measuring marks
• Erlenmeyer flask


  Has a narrow neck, used to swirl and shake solutions without splashing
• Volumetric flask


  Used to produce solutions with very precise concentration, add solid, dissolve, then fill to line to get desired volume
• Acid-base titration

  Dispense acid into Erlenmeyer flask, add indicator, use buret to dispense base until indicator changes color (endpoint)
• Titration equation


  Molarity of acid x volume of acid = molarity of base x volume of base (at equivalence point)
• pKa


  Negative log of the Ka of the weak acid, equal to the pH halfway to the equivalence point on the titration curve
• Equivalence point


  Moles of acid = Moles of base
• Separation techniques


  • Filtration
  • Distillation
  • Chromatography
• Filtration


  Used to separate a solid from a liquid, like isolating a precipitate
• Distillation


  Used to separate liquids with distinctly different boiling points, like alcohol and water
• Chromatography


  Used to separate relatively small amounts of different components in a solution, like column chromatography
• Spectrophotometry


  Select wavelength with highest absorbance, create calibration curve, use to estimate unknown concentration
• Errors in experiments


  Can be analyzed using the relevant equations (e.g. Beer-Lambert Law, Ideal Gas Law)
• Percent error


  Absolute value of (calculated answer - correct answer) / correct answer x 100