Quantitative Analysis Quiz

Quantitative Analysis

• Determines the amount of a substance in a sample.

Volumetric Analysis (Titration)

• Method of quantitative analysis that measures the volume of a solution of known concentration (standard solution) required to react completely with a sample of unknown concentration.
• Acid-base, precipitation, complex-formation, and redox titrations are types of volumetric analysis.

Gravimetric Analysis

• Method of quantitative analysis that measures the weight of a substance in a sample.

Instrumental Analysis

• Method of quantitative analysis that relies on instruments to measure the amount of a substance in a sample.

Standard Solutions

• Solutions of known concentration used in volumetric analysis.
• Classified as primary or secondary depending on their preparation and stability.

Equivalence Point

• Point in a titration where the amount of titrant added is stoichiometrically equivalent to the amount of analyte in the sample.

End Point

• Point in a titration where a visual indicator signals the completion of the reaction.

Titration Methods

• Direct Titration: Titrant is added directly to the analyte until the end point is reached.
• Back Titration: A known excess of titrant is added to the analyte, then a second titrant is used to react with the excess titrant to determine the amount of analyte.
• Displacement Titration: A reagent reacts with the analyte to displace a substance that is then titrated with a standard solution.

Acid-Base Theories

• Arrhenius Theory: Acids produce hydrogen ions (H⁺) in solution, while bases produce hydroxide ions (OH⁻).
• Bronsted-Lowry Theory: Acids donate protons (H⁺), while bases accept protons.
• Lewis Theory: Acids accept electron pairs, while bases donate electron pairs.

Buffer Solutions

• Solutions that resist changes in pH upon the addition of small amounts of acid or base.
• Composed of a weak acid and its conjugate base, or a weak base and its conjugate acid.

Acid-Base Indicators

• Substances that change color in response to changes in pH.
• Used to visually detect the end point of a titration.

Titration Curves

• Plots of pH versus volume of titrant added during a titration.
• Used to determine the equivalence point and choose an appropriate indicator.

Applications of Acid-Base Titrations

• Determination of:
  • Acids (weak and strong)
  • Bases (weak and strong)
  • Salts
  • Mixture of acids
  • Mixture of bases
  • Proteins and nitrogen compounds (Kjeldahl method)
  • Biphasic Titration