Question 27 – Elements, compounds and mixtures - Questions

The table below shows some mixtures and possible separation techniques.

Identify the most suitable separation method for each of the mixtures listed.

Mixture	Chromatography	Simple distillation	Filtration	Fractional distillation
W: red pigment from a mixture of food dyes
X: methanol from a mixture of methanol and water
Y: calcium carbonate from a suspension of calcium carbonate in water
Z: pure water from a solution of potassium chloride

Which of the mixtures, W, X, Y, or Z, contains an insoluble solid?

Pure dry crystals of nickel(II) sulfate can be prepared from a nickel(II) sulfate solution using crystallisation.

The steps below describe this experimental procedure, but they are currently in the wrong order:

V: gently heat the solution in an evaporating basin to evaporate some of the water
W: place the wet crystals in a desktop or warm oven to dry
X: allow the saturated solution to cool slowly so crystals can form
Y: dip a cold glass rod into the hot solution to check for crystal formation
Z: filter the mixture using a funnel and filter paper to collect the crystals

Show the correct sequence of steps by writing the correct letters in the empty boxes below. One letter has been filled in for you:

\boxed{\phantom{\text{V}}} \quad \boxed{\text{Y}} \quad \boxed{\phantom{\text{V}}} \quad \boxed{\phantom{\text{V}}} \quad \boxed{\phantom{\text{V}}}