Chemistry 5070 · O Level · Separation and purification
Separation and purification — practice question
Carbon and copper(II) oxide are each black solids. Copper(II) oxide reacts with dilute sulfuric acid to give an aqueous solution, whereas carbon neither reacts with nor dissolves in dilute sulfuric acid. In addition, neither carbon nor copper(II) oxide dissolve in water.
The mixture contains only carbon and copper(II) oxide.
(main)[5]
Plan an experiment that will produce a pure carbon sample from the mixture. You may use dilute sulfuric acid, distilled water and any apparatus normally available in a chemistry laboratory. No other chemicals are provided. Your plan should describe how to dissolve the copper(II) oxide, how to separate the carbon, how to purify the carbon, and what is observed at each stage. Chemical equations are not required.
Worked solution & mark scheme
This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Place the mixture in acid and shake / stir / heat it” …