Chemistry C3: Chemical Detection

Chemistry C3 Topic 3 - Chemical Detection

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  • Created by: Sarah
  • Created on: 03-05-10 16:22

Tests for Positive Ions

Flame Test-Compound want to know what’s in it:

· Sodium: Yellow

· Potassium: Lilac

· Calcium: Brick Red

· Copper: Blue-Green ♫ S, P, C, C, yellow, lilac red and green!!! ♫

Coloured Precipitate-Add Sodium Hydroxide: Many metal hydroxides = insoluble and precipitate out of solution, coloured.

Metal Colour of Precipitate Ionic Reaction

Calcium, Ca²+ White Ca²+(aq) + 20H-(aq) → Ca(OH) 2(s)

Copper(II), Cu²+ Blue Cu²+(aq) + 20H-(aq) → Cu(OH)2(s)

Iron(II), Fe²+ Sludgy Green Fe²+(aq) + 20H-(aq) → Fe(OH)2(s)

Iron(III) Fe³+ Reddish Brown Fe³+(aq) + 30H-(aq) → Fe(OH)3(s)

Aluminium, Al³+ White then redissolves Al³+(aq) + 30H-(aq) → Al(OH)3(s)

→ colourless Then Al(OH)3(s) + 0H- → Al(OH)4-(aq)

Ammonium, NH4+ No precipitate but smells

of NH4+

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Tests for Positive Ions continued...

Cool women catch birds in gross icky round arched cottages

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Tests for Negative Ions

Hydrochloric Acid - Detects Carbonates and Sulphites

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flame test bit is useful but the rest is unclear

i meant to rate it 3

Rebecca dell

The rhymes are really useful, thanks

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