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Flashcards in Flame tests Deck (9)
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Why is analysis important

to check composition of substances eg quality control manufacturing and detect polution


Define flame test

analytical technique using fact that when heated atoms of different metals emit different frequencies of light a and are seen as different colours


What is a flame test an eg of?

emission spectroscopy


Colours in flame test for cations.

Barium (Ba2+) - apple green flame
Calcium (Ca2+) - orange/red flame
Copper (Cu+ and Cu2+) - Blue green flame
Potassium (K+) - Lilac
Sodium (Na+) - Orange


Cause of coloured light?

Electrons orbit nucleus in a distant energy levels.
if energy supplied to atom , some electrons may absorb a quantum of extra energy and jump to a higher (outer) energy level.
These electrons are in excited state.
Eventually excited electron falls back to original position.- ground state- giving out extra energy as drops.
Extra energy emitted as visible light.
Amount of energy determines wave length and colour of light.


Each element has own

Unique electron configuration.
Characteristic pattern of wavelengths absorbed and emitted.
Called element's spectrum


Element's spectrum can identify what

To measure how much element is present in sample being tested.


What component of salts is responsible for colours observed?



Why must clean watch glass be used for each test?

If salt left from previous test, may mix with intended salt to use next causing inaccurate results.