RP 01 Making standard solution+acid-base titrations

• What is a standard solution?

  A standard solution is a solution of known concentration.
• How do you make a standard solution?

  • Measure, using a balance, the mass of solid required.
  • Transfer this to a volumetric flash and rinse the remaining weighing bottle content (with distilled water) into the flask so no solid is lost
  • Add a volume of distilled water to dissolve the solid. Swirl to mix.
  • Then add more distilled water up to the line on the volumetric flask. Invert multiple times to mix.
• What is the weighing by difference technique?

  Mass of substance = mass of weighing dish and substance - mass of dish after substance has been transferred
• What equipment is used to carry out a titration?

  • Pipette + pipette filler used to accurately measure out the volume of a reactant before transferring it to a conical flask
  • Burette to add small volumes of one reatant to the other reactant until end point
• How do you carry out a titration?

  • Once pipette has been used to place one reactant into the conical flash, fill the burette with the other reactant. Record initial volume
  • Add a few drops of indicator to the conical flask
  • Open burette tap and allow for the reactant to flow into the conical flask, swirling it to mix the contents
  • Close the burette tap once expected colour change occurs, and use a white tile for better visibility of colour change
  • Record final burette volume
  • Repeat until concordant results are found and calculate mean titre
• Why are acid-base indicators used?

  To detect when a reaction reaches completion usually by the presence of a colour change