FLAME TESTS

Question 1

explain the process of preparing and doing a flame test

Answer 1

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

Question 2

Lithium (Li+)

Answer 2

crimson red

Question 3

Sodium (Na+)

Answer 3

yellow

Question 4

Potassium (K+)

Answer 4

lilac

Question 5

Calcium (Ca+)

Answer 5

orangey red

Question 6

Copper ion

Answer 6

green

Question 7

problems with using flame tests

Answer 7

• 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

Question 8

explain the process of flame emission spectroscopy

Answer 8

• 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)

Question 9

what type of method is flame emission spectroscopy an example of

Answer 9

instrumental method

Question 10

3 advantages to instrumental methods

Answer 10

• 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)