experiment 2

• Dilution formula: C1V1 = C2V2

  • C1 = original concentration
  • V1 = volume of the undiluted reagent
  • C2 = desired concentration
  • V2 = desired volume of the diluted reagent
• Percent by mass formula: %m = (msolute / msolution) x 100
• Most reactions in chemistry happen in aqueous systems
• In determining the concentration of acetic acid in vinegar, we react with a certain volume of a base (like NaOH) of known concentration
• Preparation of reagents used in analytical chemistry is done using a specialized glassware called a volumetric flask
• Volumetric flask is among the most accurate glassware with a tolerance of less than 0.2%
• A volumetric flask is a bulb-like glassware with a very long and slender neck which makes it easier to read the meniscus precisely
• In preparing solutions, you first must identify the correct amount of the reagent to be used and the final volume of the desired solution
• The flask is first filled with water to at least a third its volume, then the reagent and water are swirled to ensure full dissolution
• Additional water will be added into the flask using a wash bottle or droppers until the calibration mark is reached
• When preparing a solution using a liquid reagent, it is advisable to use a pipette to deliver the solution into the flask
• The precision of mass and the volume of water added will determine the accuracy of the concentration of the prepared solution
• The amount of the reagent needed to be placed into the volumetric flask can be calculated using concentration formula or dilution formula
• The common concentration unit in analytical laboratories is molarity
• The formula for molarity is given as M = mol / V(L), where mol = amount of substance (mass MM), V(L) = volume of solution in liters
• When preparing solutions from a concentrated liquid reagent, the dilution formula is used instead