FLAME TESTS Flashcards
1
Q
explain the process of preparing and doing a flame test
A
pass the nichrome wire through a bunsen burner
add the sample to nichrome wire
pass through the blue flame on a bunsen
the color of the flame can be used to work out the metal ion present
2
Q
Lithium (Li+)
A
crimson red
3
Q
Sodium (Na+)
A
yellow
4
Q
Potassium (K+)
A
lilac
5
Q
Calcium (Ca+)
A
orangey red
6
Q
Copper ion
A
green
7
Q
problems with using flame tests
A
- the color of the flame test can be difficult to distinguish if there is a low concentration of the metal ion
- if the sample contains a mixture of metal ions it can mask the color of the flame
8
Q
explain the process of flame emission spectroscopy
A
- a sample of the metal ion in solution is placed into a flame
- the light given out is passed into a spectroscope
- which converts the light into a line spectrum
- THE POSITIONS OF THE SPECTRUM ARE SPECIFIC FOR THE GIVEN METAL ION AND CAN TELL YOU THE CONCENTRATION OF A METAL ION (the lines become more intense at a higher concentration)
9
Q
what type of method is flame emission spectroscopy an example of
A
instrumental method
10
Q
3 advantages to instrumental methods
A
- rapid (analyse samples more quickly)
- sensitive ( flame emission spectroscopy will work even on a tiny sample of a metal compound)
- accurate (flame emission spectroscopy is more likely to identify a metal ion correctly than a flame test)