chemistry qualitive analysis, materials and nanoparticles

Flame tests (metal ions~)

• light a blue flame

• Clean a platinum/ nichrome metal wire loop (with hydrochloric acid)

• Pick up sample → edge of flame

What colour :)?

Strontium -

Sodium-

Potassium -

Barium -

Calcium -

Lead -

Crimson

Orange

Lilac

Apple-green

Brick-red

Blue/white

Why is flame photometry good?

More accurate/ sensitive

How do we test for positive ions?

Add sodium hydroxide solution → form precipitate

How to test difference between magnesium, calcium, aluminium, copper and iron ion precipitates?

Mg2+ - white Precipitate

Ca2+ - ‘ ‘ Red flame

Al3+ - ‘ ‘ dissolves in excess sodium hydroxide solution

Cu2+ - blue

Fe2+ - green

Fe3+ - brown

How do we test for ammonium ions? (NH4+)

• add sodium hydroxide solution

• Warm gently

• Ammonium gas produced (rly stinky NH3)

• Changes damp red litmus → bluee

How do we test for carbonate ions - CO3 2-

Add dilute acid

CO2 produced

Gas bubbled through limewater → cloudy

Sulphate ions SO4 2-

Add hydrochloric acid (removes CO3 2-)

Add barium chloride solution

Barium sulphate precipitate form

Halide ions F-/ Cl-/ Br-/ I-

Add nitric acid

Add silver nitrate solution → precipitate

Cl- white

Br- cream

I- yellow

67 = :P …

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