- wire dipped in hydrochloric acid
- lithium L1+ bright red
- sodium Na+ golden yellow / orange
- potassium K+ lillac (purple)
- calcium Ca2+ brick red
- barium Ba+ apple green
-
ions in solution
-
ionic compunds
-
dissolve in water
- solutions
-
add sodium hydroxide
- insoluble metal hydroxide
- ca2+ (aq)
- Ca(OH)2 (s)
- white
- not dissolve in excees NaOH
- Cu2+ (aq)
- Cu(OH)2 (s)
- light blue
- Fe2+ (aq)
- Fe(OH)2 (s)
- green
- +air
- oxidises
- Fe3+ / Fe(OH)3
- reddish brown
- Mg2+ (Aq)
- Mg(OH)2 (s)
- white
- not dissolve in excess NaOH
-
ammonium ions
-
NH4+
- ammonium solution
- add dilute NaOH
-
damp red litmus paper
- blu eif ammonia formed
-
Anions
-
Solid
- + dilute hydrochloric acid
- + dilute sulphuric acid
- gas into lime water
- cloudy = solid contains carbonate
- 2HCl + Na2CO3 (carbonate) ---> 2NaCl + H2O + CO2
- 2HNO3 (nitric acid) + ZnCO3 (carbonate) ---> Zn(NO3)2 (nitrate) +H2O + CO2
-
thermal decomposition
- copper (II) carbonate (green) ---> copper (II) oxide (black) + CO2
- CuCO3 (s) ---> CiO (s) + CO2 (g)
- not all decompose on heating!
-
in solution
-
like chloride ion
- Br- (aq)
- AgBr
- ceram precipitate
- I- (aq)
- Agl
- yellow precipitate
- silver halides
- + light
- reduced to silver
- dark grey / black
- photographic process
-
NO3- (aq)
- + NaOH
- warm
- + aluminium powder
- red litmus paper goes blue
-
gases
-
hydrogen
-
lighted splint
- pop / squeaky
-
oxygen
-
glowing splint
- flame
-
carbon dioxide
-
limewater
- cloudy
-
ammonia
-
NH3
-
damp red litmus / universal indicator paper
- blue
-
sulphur dioxide
-
SO2
-
damp potassium dichromate (VI) paper
- orange to green
-
solubility of salts in water
- all common sodium, potassium, ammonia salts are soluble
- all nitrates are soluble
- common chlorides soluble, except silver chloride
- common sulphates soluble, except barium & calcium
- common carbonates and hydroxides are INSOLUBLE, except those of sodium, potassium and ammonium.
-
making insoluble salts
-
precipitate
- solid made in solution
- soluble salt (aq) + soluble salt (aq) ---> insoluble salt (precipitate) + soluble salt (aq)
- Na2CO3(aq) + CuSO4 (aq) ---> CuCO3 (s) + Na2SO4(aq)