Tests For Gases And Water Flashcards
Test for oxygen-
Oxygen relights a glowing splint.
Test for carbon dioxide-
Turns limewater cloudy.
Test for hydrogen-
Makes a ‘squeaky pop’ with a lighted splint.
Test for ammonia-
Turns damp rep litmus paper blue (strong smell)
Test for water-
When copper sulfate is bound to water, it forms blue crystals.
If you heat the blue hydrated copper sulfate crystals, it drives the water off.
It leaves a white anhydrous copper sulfate, which doesn’t have any water bound to it.
If you then add a couple of drops of water to the white powder, you get the blue crystals back again .
OR
boiling point- 100°c
Freezing point-0°c
Test for carbonates-
Add dilute hydrochloride acid to sample if carbonates are present- bubbles of carbon dioxide will be released.
Test for sulfates-
Add dilute hydrochloride acid, then barium chloride.
A white precipitate of barium sulfate means the original compound was a sulfate.
Test for halides( Cl-, Br-, I-)
Add dilute nitric acid, followed by silver nitrate solution
Outcomes:
-chloride: white precipitate of silver chloride
-bromine: cream precipitate of silver bromide
-iodine:yellow precipitate of silver iodide
Colour for flame test of cations
Lithium- crimson red
Sodium-yellow-orange
Potassium-lilac
Calcium-brick-red
Some metals form a coloured precipitate with NaOH, what are the colours formed with
- copper (||), Cu2+
- iron(||),Fe2+
- iron(||), Fe3+
Cu2+ is blue
Fe2+ is sludgy green
Fe3+ is reddish brown
Alkane +oxygen —->
Carbon dioxide + water
Halogens react with alkanes to form….
In the presence of …..
In these reactions, a hydrogen is replaced by a chlorine or bromine, making it a ….. Reaction.
Haloalkanes
Ultraviolet light
Substitution reaction
Test for chlorine-
Bleaches damp litmus paper, turning it white. (It may turn red for a moment because a solution of chlorine is acidic.
