Separation of Mixtures/Solubility

At a stage in the process of extracting sucrose from sugar cane, lime is added to the sucrose solution in order to

• lower the pH of the solution

• raise the pH of the solution

• stop the sucrose changing into sugars

• increase the percentage of sugar that would crystallize out

A mixture of copper(II) oxide and copper(II) sulfate is BEST separated by

• distilling the mixture

• heating the mixture and condensing

• shaking with excess water and then filtering

• shaking with excess water followed by fractional distillation

A separating funnel can be used to separate a mixture of

• kerosene and water

• kerosene and ethanol

• solid sodium chloride and water

• solid sodium chloride and kerosene

The pH of fresh sugar cane juice which is usually in the range 5.0 - 5.5 can be changed to 7.5 - 8.0 for more efficient processing by adding

• acetic(ethanoic) acid, CH₃CO₂H

• limestone, CaCO₃

• slaked lime, Ca(OH)₂

• sodium chloride, NaCl

From which of the following substances can a solid be obtained by process of sedimentation?

• Gels

• Foams

• Emulsions

• Suspensions

Which of the following statements correctly describes the effect of temperature on the solubility of solids in water?

• As temperature increases, the solid melts

• As temperature increases, less solid dissolves

• As temperature decreases, solubility decreases

• As temperature decreases, there is no change in solubility

Which of the following techniques may be used to separate a mixture of plant pigments into their individual components?

• Centrifugation

• Solvent extraction

• Fractional distillation

• Paper chromatography

Separation of mixtures is based on specific properties of the components in the mixture. Which of the following properties is used to separate a mixture of oil and water?

• Solubility

• Viscosity

• Particle size

• Boiling point

Which of the following separation techniques is NOT used during the extraction of sucrose from sugar cane?

• Filtration

• Precipitation

• Centrifugation

• Chromatography

A protein, X, is hydrolysed using a dilute acid. The BEST method of separating and identifying the products is by

• Chromatography

• Crystallization

• Distillation

• Fractional distillation