ALL IGCSE EDEXCEL CHEMISTRY TESTS

Test to identify H2 and observation

test: Lighted splinter

observation: Burns with a squeaky pop

Chemical test to identify H2O and observation

Test: Add anhydrous CuSO4 to liquid

Observation: White crystals turn blue (hydrated CuSO4 formed)

Physical test to identify H2O

Test: measure boiling point

observation: 100C confirms pure H20 or freezing temperature is 0C

Test to identify O2 gas and observation

test: glowing splint

observation: relights the splint

Test to identify CO2 gas and observation

Test: Bubbling through limewater

Observation: limewater turns milky/ cloudy

Test to identify CL2 gas and observation:

Test: Damp blue litmus paper or damp starch-

iodide paper

Observation: Litmus paper turns red then

bleaches it white

starch-iodide paper turns blue-black

sharp choking smell

Test for cations

Flame test:

1- Clean a Pt or Nichrome wire by dipping it into concentrated HCL acid

2- Place it in a roaring bunsen flame

3-repeat until the wire produces no colour in flame

4- then dip into fresh HCL (aq) and into solid sample

5-place in a non-roaring, non-luminous bunsen flame

flame colour for lithium

Li+ =carmine-red

flame colour for Potassium

K+=Lilac

Flame colour for sodium

Na+= yellow/orange

flame colour for calcium

Ca2+ = orange-red

flame colour for barium

Ba2+= Apple Green

flame colour for strontium

Sr2+= Crimson- Red

Flame colour for copper

blue-green

Flame colour for Fe 2+ / Fe3+

Gold

Test for ammonium and observation (NH4+)

Test: add aqueous NaOH to solid / solution under test, warm the mixture.observation: pungent smelling gas produced, the gas produced turns damp red litmus paper blue

Test for ammonia (NH3) and observation

Test: Damp red litmus paperobservation: litmus paper turns blue and pungent smell

Test for precipitation reactions

Add Reagent, aqueous NaOH dropwise to the solution undertest.

Observation for Cu2+

blue precipitate

Observation for Fe2+

grey-green precipitate

Observation for Fe 3+

reddish-brown precipitate

Test for Halide ions

Add diluted HNO3 acid followed by a few drops of AgNO3 solution, to an aqeuous solution of the solution undertest

observation for Cl-

White precipitate

observation for Br-

cream precipitate

Observation for I-

Yellow precipitate

Test for sulphate ion( SO4^2- ) and observation

Test: add diluted HCL acid followed by a few drops of BaCL2 solution or Ba(NO3)2Observation: white precipitate