chemical tests Flashcards
describe the method of flame tests
- dip wire into nichrome wire into hydrochloric acid
- dip wire into a sample of solid
- place tip of wire into roaring flame of a bunsen burner
what colour does Li+ produce in a flame test
red
what colour does Na- produce in a flame test
yellow
what colour does K+ produce in a flame test
Lilac
what colour does Ca+ produce in a flame test
orange
what colour does Cu+ produce in a flame test
green
describe the method for forming precipitate
- dissolve sample in water
- add a few drops of NaOH
what colour does the Cu2+ precipitate form
Blue
what colour does the Fe2+ precipitate form
green
what colour does the Fe3+ precipitate form
brown
describe the test for ammonia
- dissolve sample in water
- add NaOH and heat it
- test gas with damp red litmus paper
- red litmus will turn blue if NH3 ions are present
what is the test for hydrogen
- place lit splint into a tube of hydrogen
- will make a squeaky pop noise
what is the test for oxygen
- place in a glowing splint into a tube
- splint will relight
test for carbon dioxide
bubble through with limewater solution will turn cloudy
test for chlorine
- bleaches damp blue litmus paper white
describe the method for testing for halides using silver nitrate
- dissolve sample in water
- add nitric acid
- add silver nitrate
what colour precipitate is formed from Cl-
white
what colour precipitate is formed from Br-
cream
what colour precipitate is formed from I-
yellow
describe the method for testing for carbonates
- add HCl
- if effervescence occurs bubble through with limewater and if it turns cloudy it is carbonate
describe the method for testing for sulphate
- add HCl
- if effervescence doesnt occur add Barium chloride and it will form a white precipitate
