Topic 10 - Analysis Flashcards
1
Q
what are flame tests used for?
A
You can carry out a flame test to test for metal ions within compounds.
2
Q
how are flame tests carried out
A
- clean a nichrome wire loop by dipping in hydrochloric acid and rinsing with distilled water
- dip the loop into the sample you want to test
- put it in the clear blue part of the flame
- record colour of flame
3
Q
potassium flame test colour
A
lilac
4
Q
cooper flame test colour
A
green
5
Q
sodium flame test colour
A
yellow
6
Q
lithium flame test colour
A
crimson - red
7
Q
calcium flame test colour
A
orange - red
8
Q
Precipitation reaction
A
- the metal hydroxide formed is insoluble and precipitates out of solution when formed
- add Sodium Hydroxide to solution of metal ions and note down the colour of precipitate
9
Q
calcium precipitate
A
white
10
Q
copper precipitate
A
blue
11
Q
iron ( Fe2+) precipitate
A
green
12
Q
iron ( Fe3+ ) precipitate
A
brown
13
Q
aluminium precipitate
A
white , redissolves in excess NaOH to become colourless
14
Q
Ammonium ions test (NH4+)
A
- hold a piece of damp, red litmus paper over ammonia gas
- if the gas is ammonia, it will turn blue
15
Q
testing for Carbonate ions
A
- if you add acid to a carbonate it should react to produce carbon dioxide gas as one of its products
- bubble the gas produced through limewater
- if the limewater turns cloudy it is a carbonate
