analysis lec

Subdecks (3)

Cards (161)

  • Volumetric Analysis
    A method that involves the measurement of the volume of a solution of known concentration which is used in order to determine the concentration of the analyte
  • Standard Solution
    Also known as Volumetric Analysis
  • Titrimetric Analysis
    The concentration of a solution is determined by causing the solution to react with another solution of known concentration
  • Normal Solution
    Contains gram-equivalent of substance that is dissolved in 1 liter of solution (Normality of the Solution)
  • Molar solution

    Contains 1 mol of the substance that is dissolved in 1 liter of solution
  • Quantitative analysis
    How much is present in a specific solution
  • Volumetric Analysis
    1. A + B = C
    2. Volume
  • Gravimetric analysis
    1. A + B = C
    2. Weight
  • Volumetric Apparatus
    • Beaker
    • Erlenmeyer
    • Graduated cylinder
  • Volumetric Apparatus (made to deliver)
    • Burette
    • Pipette
    • Graduated cylinder
  • Types of Burette
    • Mohr Burette - alkalimetry: 1 ml subd
    • Geissler Burette - acidimetry
  • Sources of Error in The Use of Volumetric Apparatus
    • Improper cleaning of the apparatus
    • Parallax Error
    • Variation in Temperature
    • Air bubbles that trap
  • Standard Solution
    A solution whose concentration is known
  • Primary Standard
    A highly purified compound that serves as a reference material in all volumetric methods
  • Properties of Primary Standard
    • Chemically Pure
    • Chemically Stable
    • Easily Prepared
    • Water Soluble
    • Reacts stoichiometrically with the sample
    • With fairly high equivalent weight
  • Secondary Standard
    A compound whose purity has been established by chemical analysis and it would be preserved as the reference material for the titrimetric method of analysis
  • Analyte
    The solution whose concentration has to be determined
  • Indicator
    A substance that changes color of the solution in response to a chemical change
  • Standardization
    A process that is used to determine the concentration of a solution of known concentration by titration
  • Equivalent Point
    The point in titration when stoichiometrically different amounts of analyte and titrant react
  • Endpoint
    The point in titration where we stop adding the titrant
  • Titration error

    The determinate error in titration due to the difference between the endpoint and equivalence point
  • Types of Chemical Reaction
    • Neutralization Titration
    • Complexometric Titration
    • Precipitation Titration
    • REDOX Titration
  • LEORA
    Less Electron Oxidized Reducing Agent
  • GEORA
    Gain Electron Reduced Oxidizing Agent
  • Theories in the change of color of INDICATORS
    • Physiochemical Theory
    • Organic Theory
    • Colloidal Theory
  • Properties used to detect End Points (Volumetric Analysis)
    • Color change
    • Turbidity changes resulting from the formation or disappeared of solid phase
    • Electric conductivity of the solution
    • Electric potential between a pair of electrodes immersed in the solution
    • Temperature of the solution
  • Elements of Manual Titration
    • Burette
    • Titrant
    • Analyte
    • Indicator
    • Processor
    • Detector
  • Difficulties in Manual Titration
    • Reading the meniscus
    • Filling of burette with titrant
    • Reading the volume of the titrant
    • Determination of end point
    • Standardization of titrant
    • Error in computation
  • Automatic Titration

    Involves electrochemical sensing technique
  • Applications of Titrimetry in Pharmaceutical Analysis
    • Provide standard pharmacopeial methods for assay of unformulated drugs and excipients
    • Used for standardization of raw materials and intermediates used in drug synthesis in industry
    • Certain specialist titrations, such as the Karl Fischer titration used to estimate water content, are widely used in the pharmaceutical industry
  • Types of Titration
    • Direct Titration
    • Indirect Titration
    • Residual/Back Titration
  • Direct Titration
    The analyte is reacted with the titrant after rendering its solubility in the titration medium
  • Indirect Titration
    The sample is converted to an intermediate product that is titrated with the standard solution
  • Residual/Back Titration
    Measured excess of the standard solution is added to the sample to accomplish a desired reaction and the excess is back titrated with a 2nd standard solution
  • Reasons for performing back titration
    • When the reaction between the analyte and titrant proceeds slowly
    • When the reaction between titrant and analyte does not give a sharp endpoint with the indicator
    • When the sample or analyte cannot be brought to solution without changing the chemical nature upon which the titration reaction is based
  • Acid/Base Titration

    Also known as Neutralization Titration
  • Neutralization Reaction
    A solution of an acid is usually added to a solution of a base until the base is exactly neutralized and neither acid nor base exists
  • Properties of Acids
    • Taste sour
    • React with some metals to give off hydrogen gas
    • Conduct electricity in solution
  • Properties of Bases
    • Taste bitter
    • Feel slippery
    • Dissolve fats and oils