sc25 Flashcards
Why is the test for any ion unique?
Otherwise you would never know which specific ion it was if more than 1 ion gave the same result
How would you carry out a flame test?
- hold a sample of the ion on a wire
- put it in a roaring Bunsen burner flame
- observe result colour
What colour is lithium ions (Li+)?
Red
What colour are sodium ions (Na+)?
Yellow
What colour are potassium ions (K+)?
Lilac
What colour are calcium ions (Ca2+)?
Orange-red
What colour are copper ions (Cu2+)?
Blue-green
How would you identify aluminium ions (Al3+) in a sodium hydroxide solution?
A white precipitate forms
How would you identify calcium ions (Ca2+) in a sodium hydroxide solution?
A white precipitate forms
How would you identify copper ions (Cu2+) in a sodium hydroxide solution?
A blue precipitate forms
How would you identify iron(ll) ions (Fe2+) in a sodium hydroxide solution?
A green precipitate forms
How would you identify iron(lll) ions (Fe3+) in a sodium hydroxide solution?
A brown precipitate will form
What is the chemical test for ammonia?
- makes damp litmus paper turn blue
- forms white smoke of ammonium chloride when hydrogen chloride is held near it
how do you test for carbonate ions (CO3 2-) and identify the carbon dioxide evolved?
- use dilute acid
- bubble gas through limewater
- if limewater goes cloudy then co2 present (carbonates react with dilute acids to produce co2)
how do you test for a sulfate ion? (SO4 2-)
- add dilute hydrochloric acid
- add barium chloride solution
- white precipitate forms
