Chemical testing Flashcards
Method for testing cations
- Clean the wire (dip the end of the wire into the acid and then burn in a flame, repeat this three times)
- Dip the wire into the acid and then the solid sample
- Burn the sample in the flame
- Note the colour observed and compare to known colours
Lithium flame test
Red flame
Sodium flame test
Yellow flame
Potassium flame test
Lilac flame
Calcium flame test
Orange/red flame
Copper flame test
Blue/green flame
Method for testing for cations (Copper, Iron)
Add sodium hydroxide in excess
Copper II results (test for cations)
Blue precipitate forms of Cu(OH)2
Iron (II) results (test for cations)
Green precipitate forms of Fe(OH)2
Iron (III) results (testing for cations)
Rust coloured precipitate forms of Fe(OH)3
Describe test for ammonium ions
Add sodium hydroxide, Heat the reacting mixture, test the gas produced using damp red litmus paper
Results of testing for ammonium ions
- No precipitate formed
- Gas turns damp red litmus blue
Testing for halides method
Add dilute nitric acid then Add a small amount of silver nitrate solution
chloride test results (testing for anions)
Turns to a white precipitate
bromide test results
Cream precipitate formed
iodide test results (testing for anions)
Yellow precipitate formed
Describe test for sulphates
Dissolve in water, add barium chloride
Sulphates test results
White precipitate formed (of barium sulphate)
Describe test for carbonates
Add hydrochloric acid, bubble gas through limewater
Carbonate test results
Calcium carbonate effervesces
Limewater turns cloudy white
Test for chlorine
Add damp blue litmus paper
Result for test for chlorine
Turns from blue to pink then it is bleached
Test for oxygen
Add a glowing splint
Results for test for oxygen
The splint relights
