Colour Changes Flashcards
How do you test for hydrogen?
Use a lit splint and hold it at the end of the test tube.
A ‘squeaky pop’ should sound.
How do you test for oxygen?
Use a glowing splint inserted into a test tube.
It should relight if oxygen is present.
How do you test for carbon dioxide gas?
Bubble the gas through limewater.
It will turn cloudy.
How do you test for chlorine?
Use damp litmus paper.
The litmus paper should turn white.
What colour flame does lithium produce?
Crimson.
What colour flame does sodium produce?
Yellow.
What colour flame does potassium produce?
Lilac.
What colour flame does calcium produce?
Orange-red.
What colour flame does copper produce?
Green.
What happens when NaOH is added to copper (II) ions?
A blue precipitate forms.
What happens when NaOH is added to iron (II) ions?
A green precipitate forms.
What happens when NaOH is added to iron (III) ions?
A brown precipitate is produced.
What happens when NaOH is added to aluminium ions?
A white precipitate will form which will then dissolve with excess sodium hydroxide.
How do you test for carbonate ions?
React with a dilute acid such as HCl.
Bubble the gas through limewater.
If it turns cloudy then carbonate ions are present.
How do you test for halide ions?
Add dilute nitric acid, followed by silver nitrate solution.
Chloride gives a white precipitate.
Bromide gives a cream precipitate.
Iodine gives a yellow precipitate.
