Flame tests

Question 1

Why is analysis important

Answer 1

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

Question 2

Define flame test

Answer 2

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

Question 3

What is a flame test an eg of?

Answer 3

emission spectroscopy

Question 4

Colours in flame test for cations.

Answer 4

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

Question 5

Cause of coloured light?

Answer 5

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.

Question 6

Each element has own

Answer 6

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

Question 7

Element’s spectrum can identify what

Answer 7

Element.

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

Question 8

What component of salts is responsible for colours observed?

Answer 8

Metals

Question 9

Why must clean watch glass be used for each test?

Answer 9

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