O-Level Chemistry Practical: Qualitative Analysis and Gas Tests

anion

A negatively charged ion.

carbonate (CO32-)

An anion that consists of one carbon atom and three oxygen atoms.

chloride (C/-)

An anion formed from chlorine.

iodide (I-)

An anion formed from iodine.

nitrate (NO3)

An anion consisting of one nitrogen atom and three oxygen atoms.

sulfate (SO42-)

An anion that consists of one sulfur atom and four oxygen atoms.

dilute nitric acid

A diluted solution of nitric acid used to acidify solutions.

aqueous silver nitrate

A solution containing silver nitrate used in qualitative analysis.

aqueous sodium hydroxide

A solution of sodium hydroxide used to test for cations.

aluminium (Al3+)

A cation that forms a white precipitate, soluble in excess.

ammonium (NH4)

A cation that produces ammonia when warmed.

calcium (Ca2+)

A cation that forms a white precipitate.

copper(II) (Cu2+)

A cation that forms a light blue precipitate, insoluble in excess.

iron(II) (Fe2+)

A cation that forms a green precipitate, insoluble in excess.

iron(III) (Fe3+)

A cation that forms a red-brown precipitate, insoluble in excess.

lead(II) (Pb2+)

A cation that forms a white precipitate, soluble in excess.

zinc (Zn2+)

A cation that forms a white precipitate, soluble in excess.

ammonia (NH3)

A gas that turns damp red litmus paper blue.

carbon dioxide (CO2)

A gas that gives a white precipitate with limewater.

chlorine (Cl)

A gas that bleaches damp litmus paper.

hydrogen (H2)

A gas that 'pops' with a lighted splint.

oxygen (O2)

A gas that relights a glowing splint.

sulfur dioxide (SO2)

A gas that turns aqueous acidified potassium manganate(VII) from purple to colourless.