unit 4 chemistry cover Flashcards

1
Q

What is percentage by mass?

A

The mass of solute made up to 100 cm3 of solution.

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2
Q

How is the percentage yield reduced?

A

By:
♦ mass transfer or mechanical losses
♦ purification of product
♦ side reactions
♦ equilibrium position

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3
Q

What is gravimetric analysis used for?

A

To determine the mass of an element or compound in a substance.

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4
Q

What is an important complexometric reagent?

A

EDTA and can be used to determine the concentration of metal ions in solution.

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5
Q

What are the steps of recrystallisation?

A

♦ 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

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6
Q

What does thin-layer chromatography (TLC) use?

A

A fine film of silica or aluminium oxide spread over glass, aluminium foil or plastic.

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