beer law

• What is the formula for absorbance (A)?

  A = a × b × c
• What does A represent in the absorbance formula?

  Absorbance (no units)
• What does 'a' represent in the absorbance formula?

  Molar absorptivity (L·mol⁻¹·cm⁻¹)
• What does 'b' represent in the absorbance formula?

  Path length of light (cm)
• What does 'c' represent in the absorbance formula?

  Concentration of the solution (mol/L)
• How is absorbance related to concentration and path length?

  Absorbance is directly proportional to both
• What should a plot of absorbance vs. concentration yield?

  A straight line
• What does molar absorptivity (a) measure?

  How strongly a substance absorbs light
• What is the unit for molar absorptivity (ε)?

  L·mol⁻¹·cm⁻¹
• What is the path length (b) in the absorbance formula?

  Always 1 cm
• What happens to absorbance if concentration increases?

  Absorbance increases
• What is the relationship between absorbance and path length?

  Absorbance increases with longer path length
• How does changing the molar absorptivity affect absorbance?

  Higher molar absorptivity increases absorbance
• What are two common sources of error in a Beer-Lambert Law experiment? Not wiping cuvette, incorrect concentration, wrong wavelength
• What happens to absorbance if the cuvette is dirty or smudged?

  Absorbance readings increase inaccurately
• What are two possible reasons for the breakdown of linearity in a calibration curve for concentrations above 0.01 M?

  High concentration effects and solvent absorption
• What are common instrumental errors in Beer-Lambert Law experiments?

  • Calibration issues
  • Stray light interference
  • Path length inaccuracies
• What are common sample errors in Beer-Lambert Law experiments?

  • Concentration errors
  • Bubbles in the cuvette
  • Impurities in the solution
• What are common procedural errors in Beer-Lambert Law experiments?

  • Incorrect wavelength selection
  • Residual liquid in cuvette
• What are theoretical/conceptual errors in Beer-Lambert Law experiments?

  • Deviations from linearity
  • Solvent absorption
  • Refractive index effects
• How can errors be minimized in Beer-Lambert Law experiments?

  • Regular calibration of the spectrophotometer
  • Proper cuvette cleaning
  • Double-checking wavelength selection
• What equipment and materials are needed for a Beer-Lambert Law experiment?

  • Functional spectrophotometer
  • Clean cuvettes
  • Accurate pipettes and volumetric flasks
  • Known stock solutions
  • Pure solvents
• What is the preparation phase for a Beer-Lambert Law experiment?

  • Calibrate the spectrophotometer
  • Prepare dilutions from stock solutions
  • Clean cuvettes properly
• What is the execution phase in a Beer-Lambert Law experiment?

  • Proper cuvette filling
  • Wiping cuvettes to remove smudges
  • Handling cuvettes by non-optical sides
• What is the data analysis phase in a Beer-Lambert Law experiment?

  • Create a calibration curve
  • Verify linearity of data points
  • Calculate unknown concentrations
• What are common errors and how to avoid them in Beer-Lambert Law experiments?

  • Use the correct blank
  • Double-check dilution steps
  • Inspect cuvettes for contamination