Chemical Tests 2h Flashcards
Test for hydrogen
Lit splint goes out with a squeaky pop
Test for oxygen
Glowing splint relights
Test for carbon dioxide
Limewater turns milky/cloudy
Test for ammonia (NH3)
Damp red litmus turns blue
Test for chlorine
Damp blue litmus paper bleaches/turns white
Flame test
Clean platinum wire with concentrated HCl
Dip into salt
Hold wire into roaring flame
Flame colour for:
Lithium, Sodium, Potassium, Calcium, Copper (II)
Lithium: Red
Sodium: Orange
Potassium: Lilac
Calcium: Red
Copper (II): Green - Blue
Test for ammonium (NH4)
Red litmus paper & NaOh
- Damp red litmus paper turns blue
- Add warm NaOH and aluminium as catalyst. Strong odour, gas produced (NH3)
Cu (II) with NaOH
Blue precipitate formed
Fe (II) with NaOH
Green precipitate formed
Fe (III) with NaOH
Brown precipitate formed
Tests for halides
Add nitric acid to remove impurities
Add silver nitrate to cause precipitation
Chloride: white precipitate
Bromide: Cream precipitate
Iodide: Yellow predipitate
Sulphate test
Add hydrochloric acid to remove imputites
Add barium chloride
White precipitate forms if sulphate ion is present
Carbonate test
Add any acid
Should bubble
Test bubbles for carbon dioxide
Tests for water
- Anhydrous copper(II) sulphate turns from white to blue
- Cobalt chloride from blue to pink
