chemical tests

inorganic chemistry

test for hydrogen gas

lit splint produces squeaky pop in gas (makes water)

equation for hydrogen gas test

2H2(g) + O2(g) → 2H2O(l)

test for oxygen gas

relight a glowing splint

test for carbon dioxide gas

bubble gas through limewater, limewater turns cloudy (white precipitate)

equation for CO2 gas test

Ca(OH)2(aq) + CO2(g) → CaCO3(s) + H2O(l)

test for chlorine gas

damp blue litmus paper (or universal indicator paper), the green chlorine gas bleaches the paper (turns the blue litmus paper to red first)

why is chlorine test done under a fume cupboard?

chlorine gas is toxic

test for pure water

if liquid boils at 100C it is pure

test for lithium ions

flame test - red flame

test for sodium ions

flame test - yellow flame

test for potassium ions

flame test - lilac flame

test for calcium ions

flame test - red-orange flame

test for copper (II) ions

flame test - blue-green flame

are metal ion cations or anions

cations

test for copper (II) ions

dilute sodium hydroxide - forms blue precipitate

test for iron (III) ions

dilute sodium hydroxide - forms orange-brown precipitate

test for Iron (II) ions

green precipitate reacting from sodium hydroxide solution (the precipitate is Fe(OH)2)

test for ammonium gas

red litmus paper

test for ammonium ions

sodium hydroxide reacts to form ammonia gas, which (the alkaline) turns red litmus paper or universal indicator paper to blue ; this also works in a solid solution as you aren’t looking for a precipitate

test for carbonates

dilute hydrochloric acid and solution will start to bubble (fizz). bubble gas through limewater - limewater turns cloudy

test for pure and impure water

white anhydrous CuSO4 turns blue because hydrates copper (II) sulfate is formed

test for sulfates

sulfate in distilled water, add dilute hydrochloric acid and barium chloride solution - solution will produce white precipitate (of barium sulfate) 

test for chloride ion

nitric acid and silver nitrate to form white precipitate

test for bromide ions

nitric acid and silver nitrate to form cream precipitate

test for iodide ions

nitric acid and silver nitrate to form yellow precipitate