RP1

• Make up a volumetric solution and carry out a simple acid-base titration


  1. Stage 1: Transferring a known mass of the solid

  Weigh by difference

  2. Stage 2: Dissolving the solid in distilled water

  Add minimum distilled water and stir in breaker with glass rod as you want some water to rinse equipment

  3. Stage 3: Rinsing all glassware and making up the solution

  All solute must be transferred

  Invert so mixture is homogenous
• Carrying out an acid-base titration

  1. Stage 1: Preparing the conical flask

  2. Stage 2: Preparing the burette

  3. Stage 3: Performing the titration
• Effect of air bubble on first titration result

  The value of the titre would be higher (than the true value)
• Effect of air bubble on average titre

  It should have no effect as the first titration can be ignored / subsequent titrations would be accurate
• Reason for removing the funnel after filling the burette

  As a droplet from the funnel could enter the burette affect volume / readings / titre
• Other source of error in using a burette


  Air bubble in jet
• Why rinsing the conical flask improves accuracy


  (Returns) reagent on the sides of the flask to the reaction mixture (to ensure that all of the acid / alkali reacts)

  Water is not a reagent and does not change number of moles of reagent
• Why repeating a titration can increase reliability

  Idea that a single titration could be flawed / anomalous
• Why a 250cm3 conical flask is preferred over a 250cm3 beaker


  Less chance of losing liquid on swirling
• Desirable titration volume


  A titre of 40cm3 may be more desirable than 10cm3, but greater than 50cm3 would be undesirable
• Back titration to calculate the relative formula mass of a solid

  1. Stage 1: Acknowledging that the acid must be in excess

  2. Stage 2: Experimental procedure

  3. Stage 3: Calculating the molecular mass from the experimental results
• Redox titration to determine the concentration of iron(II) ions


  1. Write an equation for the reaction between iron(II) ions and manganate(VII) ions

  2. Use this equation and the information given to calculate the concentration of iron(II) ions in the original solution X