copper (II) sulphate salt
Each working group will require:
Glass beaker (100 cm3)
Conical flask (100 cm3)
Glass stirring rod
Filter funnel (Note 1)
Filter paper (Note 2)
Bunsen burner, tripod and gauze
Heat resistant mat
a Add 20 cm3 of the 0.5 M sulfuric acid to the 100 cm3 beaker. Heat carefully on the tripod with a gentle blue flame until nearly boiling. SAFETY: Be very careful not to knock the tripod while the beaker is on it.
b When the acid is hot enough (just before it starts to boil), use a spatula to add small portions of copper(II) oxide to the beaker. Stir the mixture gently for up to half a minute after each addition. SAFETY: When adding the solid to the beaker, take care to avoid knocking the beaker. c When all the copper(II) oxide has been added, continue to heat gently for 1 to 2 minutes to ensure reaction is complete. Then turn out the Bunsen burner. It may be wise to check (using pH or litmus paper) that no acid remains. If the acid has not been hot enough, excess acid can co-exist with copper oxide. If someone should decide to attempt to evaporate the acid after filtering, the lab would fill with fumes. d Allow the beaker to cool slightly while you set up Stage 2.
e Place the filter funnel in the neck of the conical flask. f Fold the filter paper to fit the filter funnel, and put it in the funnel. g Make sure the beaker is cool enough to hold at the top. The contents should still be hot. h Gently swirl the contents to mix, and then pour into the filter paper in the funnel. Allow to filter through. i A clear blue solution should collect in the flask. If the solution is not clear, and black powder remains in it, you will need to repeat the filtration.
Stage 3 (optional)
j Rinse the beaker, and pour the clear blue solution back into it. Label the beaker with your name(s). Leave the beaker in a warm place, where it won't be disturbed, for a week or so. This...
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