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Btec applied science level 3 extended diploma

please may i have some help with Unit 4 (scientific practical techniques) Assignment 2 (separating substances and estimating purity)
i need to describe the techniques used in producing aspirin using precipitation, crystallisation, filtration and drying. thanks

Reply 1

loyal.1

Original post by PP0121

hello, I know you posted this 4 years ago but right now it is what I want help on haha
if you remember could you help me with it thank you.

Reply 2

Claisen

Original post by loyal.1

hello, I know you posted this 4 years ago but right now it is what I want help on haha
if you remember could you help me with it thank you.

Crystallisation - minimum amount of hot solvent (to ensure maximum yield) until the crude sample dissolves. Add water and the (now) pure sample should crash out. This is because it is insoluble in water. May need to scratch the sides - read about nucleation point. All soluble impurities remain in the solvent.

Filtration - remove solid impurities, also allows you to wash the remaining crystals.

Drying - remove excess water.

This is all in the CGP Chemistry textbook.