purification Flashcards
explain each step in recrystallisation
the minimum amount of hot water
yo ensure the hot solution would be saturated/ crystals would form on cooling
explain each step in recrystallisation
the flask was cooled to room temperature before the crystals were filtered off
the yield would be lower if warm/ solubility higher if warm
the crystals were compressed in the funnel
air passes through the sample not just around it
allow better drying but not water squeezed out
a little cold water was poured through the crystals
to wash away soluble impurities
the melting point of the sample in the sample was found to be lower than a databook
suggest the most likely impurity to have caused this low value and an improvement to the method so that a more accurate value for the melting point would be obtained
impurity: water
improvement: press the sample of crystals between filter papers
