Topic 4- Flame tests Flashcards
1
Q
Problems with flame tests
A
- Many compounds contain sodium impurities, intense colour of sodium can mask other colours
-People have different levels of colour vision
2
Q
Test for ammonium ions
A
-Add sodium hydroxide and warm the mixture
3
Q
Reaction for testing for ammonium ions
A
NH4+ + OH- –> NH3 + H2O
4
Q
Why is concentrated HCL used in flame tests?
A
To convert a metal compound to a chloride- chlorides are more volatile than other salts give better results
5
Q
Colour of Li+
A
red
6
Q
Colour of Na+
A
yellow/ orange
7
Q
Colour of K+
A
lilac
8
Q
Colour of Rb+
A
red/ purple
9
Q
Colour of Cs+
A
blue/ violet
10
Q
Colour of Be2+
A
(no colour)
11
Q
Colour of Mg2+
A
(no colour)
12
Q
Colour of Ca2+
A
brick red
13
Q
Colour of Sr2+
A
crimson red
14
Q
Colour of Ba2+
A
apple green
15
Q
What type of wire for flame tests?
A
platinum or nichrome wire
