Identifying compounds Flashcards
What is the test for carbonates and hydrocarbonates?
Add acid to the carbonate (HCl)
Connect to test tube with limewater
If present the CO2 produced will turn limewater cloudy
What is the result of the flame-test of Sodium?
Yellow-orange flame
What is the result of the flame-test of Potassium?
Lilac flame
What is the result of the flame-test of Calcium?
Brick red flame
What is the result of the flame-test of Lithium?
Crimson red flame
What is the result of the flame-test of Rubidium?
Reddish-violet
What is the result of the flame-test of Caesium?
Blue-violet
What is the result of the flame-test of Strontium?
Red
What is the result of the flame-test of Barium?
Pale green
What is the result of the flame-test of Copper?
Blue-green
How do you perform a flame test?
Clean a nichrome wire in conc hydrochloric acid and put into Bunsen flame
Dip into small amount of solid and put into the Bunsen flame
How is the test for halide ions done?
Dissolve solid in pure water
Acidified using dilute nitric acid
Silver nitrate (aqueous) added
Why is dilute nitric acid when testing for halide ions?
Reacts with and removes other ions which may give a precipitate with silver nitrate
What coloured precipitate forms if F- ions are present in a compound?
No precipitate
What coloured precipitate forms if Cl- ions are present in a compound?
White precipitate
What coloured precipitate forms if Br- ions are present in a compound?
Cream precipitate
What coloured precipitate forms if I- ions are present in a compound?
Yellow precipitate
How does AgCl react with ammonia solution?
Dissolves in dilute ammonia solution
How does AgBr react with ammonia solution?
Precipitate doesn’t dissolve in dilute ammonia solution
Precipitate dissolves in conc ammonia solution giving colourless solution