unit 4 chemistry cover Flashcards
What is percentage by mass?
The mass of solute made up to 100 cm3 of solution.
How is the percentage yield reduced?
By:
♦ mass transfer or mechanical losses
♦ purification of product
♦ side reactions
♦ equilibrium position
What is gravimetric analysis used for?
To determine the mass of an element or compound in a substance.
What is an important complexometric reagent?
EDTA and can be used to determine the concentration of metal ions in solution.
What are the steps of recrystallisation?
♦ dissolving an impure solid gently in a minimum volume of a hot solvent
♦ hot filtration of the resulting mixture to remove any insoluble impurities
♦ cooling the filtrate slowly to allow crystals of the pure compound to form, leaving soluble impurities dissolved in the solvent.
♦ filtering, washing and drying the pure crystals
What does thin-layer chromatography (TLC) use?
A fine film of silica or aluminium oxide spread over glass, aluminium foil or plastic.
