Edexcel IGCSE Chemistry 复习笔记 2.7.6 Prepare a Soluble Salt II

Aim:

To prepare a sample of a dry salt starting from an acid and an alkali

Diagram:

Diagram showing the apparatus needed to prepare a salt by titration

 Method:

• Use a pipette to measure the alkali into a conical flask and add a few drops of indicator (phenolphthalein or methyl orange)
• Add the acid into the burette and note the starting volume
• Add the acid very slowly from the burette to the conical flask until the indicator changes to appropriate colour
• Note and record the final volume of acid in burette and calculate the volume of acid added (starting volume of acid - final volume of acid)
• Add this same volume of acid into the same volume of alkali without the indicator
• Heat to partially evaporate, leaving a saturated solution
• Leave to crystallise decant excess solution and allow crystals to dry

Results:A dry sample of a salt is obtained