key practicals

Question 1

crystilisation

Answer 1

Add 50 cm3 dilute acid into a beaker and warm gently using a Bunsen burner

Add the copper(II) oxide slowly to the hot dilute acid and stir until the base is in excess (i.e. until the base stops dissolving and a suspension of the base forms in the acid)

Filter the mixture into an evaporating basin to remove the excess base

Gently heat the solution in a water bath or with an electric heater to evaporate the water and to make the solution saturated

Check the solution is saturated by dipping a cold glass rod into the solution and seeing if crystals form on the end

Leave the filtrate in a warm place to dry and crystallise

Decant excess solution and allow the crystals to dry