Reactions of Transition Metal Ions in Solution Flashcards
Iron(II) Aqueous ion
[Fe(H2O)6]2+(aq)
green solution
Iron(II) Action of NaOH
Fe(H2O)4(OH)2(s)
green ppt goes brown on standing in air
Iron(II) Action of an excess of
NaOH(aq)
No further change
Iron(II) Action of NH3(aq)
Fe(H2O)4(OH)2(s)
green ppt goes brown
on standing in air
Iron(II) Action of an excess
of NH3(aq)
No further change
Iron(II) Action of Na2CO3(aq)
FeCO3(s)
green ppt
Copper(II) Aqueous ion
[Cu(H2O)6]2+(aq)
blue solution
Copper(II) Action of NaOH
Cu(H2O)4(OH)2(s)
blue ppt
Copper(II) Action of an excess of NaOH(aq)
No further change
Copper(II) Action of NH3(aq)
Cu(H2O)4(OH)2(s)
blue ppt
Copper(II) Action of an excess of NH3(aq)
[Cu(H2O)2(NH3)4]2+(aq)
deep blue solution
Copper(II) Action of
Na2CO3(aq)
CuCO3(s)
blue-green ppt
Iron(III) Aqueous ion
[Fe(H2O)6]3+(aq)
purple solution may look yellow-brown due to some [Fe(H2O)5(OH)]2+(aq)
Iron(III) Action of NaOH
Fe(H2O)3(OH)3(s)
brown ppt
(ppt may look orange-brown)
Iron(III) Action of an excess of NaOH(aq)
No further change
Iron(III) Action of NH3(aq)
Fe(H2O)3(OH)3(s)
brown ppt
(ppt may look orangebrown)
Iron(III) Action of an excess of NH3(aq)
No further change
Iron(III) Action of Na2CO3(aq)
Fe(H2O)3(OH)3(s)
brown ppt
(ppt may look orange-brown)
and CO2 gas evolved
Aluminium(III) Aqueous ion
[Al(H2O)6]3+(aq)
colourless solution
Aluminium(III) Action of NaOH
Al(H2O)3(OH)3(s)
white ppt
Aluminium(III) Action of an
excess of NaOH(aq)
[Al(OH)4]–(aq)
colourless solution
Aluminium(III) Action of NH3(aq)
Al(H2O)3(OH)3(s)
white ppt
Aluminium(III) Action of an excess of NH3(aq)
No further change
Aluminium(III) Action of
Na2CO3(aq)
Al(H2O)3(OH)3(s)
white ppt and CO2 gas evolved
V(V) Species in acidic solution and colour of solution
[VO2(H2O)4]+
yellow
V(IV) Species in acidic solution and colour of solution
[VO(H2O)5]2+
blue
V(III) Species in acidic solution and colour of solution
[V(H2O)6]3+
green
V(II) Species in acidic solution and colour of solution
[V(H2O)6]2+
purple
what are transition metals and its properties
metals that form one or more stable ions with a partially filled d subshell
-form complexes
-form coloured ions
-have variable oxidation states
-are good catalysts
what is a complex
central metal atom or ion surrounded by ligands
what is a ligand
molecule or ion that joins to a central transition metal atom or ion via a co ordinate bond by donating a pair of electrons
what is a coordintation number
the number of coordinate bonds to the central metal atom or ion
monodentate, bidentate, polydentate ligand
mono- ligand donates one pair
poly- 2 or more pairs
bi- 2 pairs
examples of monodentate ligands
Cl-, CN-
NH3 and H2O
examples of bidentate ligands
C2O4^2-
NH2CH2CH2NH2
example of a hexadentate ligand
EDTA^4-
what is coordination number affected by
-size of metal ion and ligands
-electronic configuration of metal ion
why do transition metal ions appear coloured
they absorb certain frequencies of light causing electrons in d sub-shell to become excited
the colour observed is the light not absorbed/the light transmitted
what factors affect the size of the energy gap between d block compounds
-transition metal ion
-oxidation state
-ligands
-shape
how to calculate energy difference
energy= planck x frequency
velocity of light= wavelength x frequency
therefore, energy= (planck x velocity) / wavelength
how to find conc of unknown solution
-make up standard solutions of coloured compounds
-choose suitable filter
-zero the colorimeter with tube of pure solvent
-measure absorbance of standard solutions and plot calibration curve
-measure absorbance of unknown solution and read off conc from calibration curve
redox of MnO4^-, Fe^2+ and C2O4^2-
MnO4^- –> Mn^2+
Fe^2+ –> Fe^3+
C2O4^2- –> CO2
what is a homogenous catalyst
-catalyst in the same phase as the reactants
-forms an intermediate compound
-intermediate breaks down to form product and catalyst reforms
show how Fe2+ acts as a catalyst for S2O8^2- to SO4^2-
slow reaction because negative ions repel
S2O8^2- + 2Fe^2+ –> 2SO4^2- + 2Fe^3+ (intermediate)
2Fe^3+ + 2I- –> I2 + 2Fe2+
what is a heterogenous catalyst and how does it work
catalyst in a different phase from the reactants
-reactants adsorb onto surface of catalyst
-the bonds in the reactant are weakened
-products desorb from catalyst surface
what is catalyst poisoning
-if the bonds are too strong, the products may remain fixed to the catalyst
-active sites blocked
what are the stages of the contact process used to make sulfuric acid
S + O2 –> SO2
2SO2 + O2 <–> 2SO3
SO3 + H2O –> H2SO4
what are the equations for the contact process with a vanadium oxide catalyst
V2O5 + SO2 –> V2O4 + SO3
2V2O4 + O2 –> 2V2O5
what does the graph for autocatalysis look like
-starts slowly as not much catalyst product has formed
-slope increases as catalyst forms
-slope decreases as reactants are being used up
why are aqua ions with a 3+ charge more acidic than those with a 2+ charge
3+ ions have a higher charge density so the OH bond is weakened
tendency to donate a H+ ions increases making the solution acidic
overall equation of reacting [M(H2O)6]3+ with XS OH-
[M(H2O)6]3+ + 3OH- –> M(H2O)3(OH)3 + 3H2O
overall equation of reacting [M(H2O)6]2+ with XS OH-
[M(H2O)6]2+ +2OH- –> M(H2O)4(OH)2 +2H2O
[M(H2O)6]3+ with NH3
[M(H2O)6]3+ + 3NH3 –> M(H2O)3(OH)3 + 3NH4+
[M(H2O)6]2+ with NH3
[M(H2O)6]2+ +2NH3 –> M(H2O)4(OH)2 + 2NH4+
reaction of Cu(H2O)4(OH)2 with XS NH3
[Cu(H2O)6]2+ + 4NH3 –> [Cu(NH3)4(H2O)2]2+ + 2H2O + 2OH-
[M(H2O)6]3+ with CO3^2-
2[M(H2O)6]3+ + 3CO3^2- –> 2M(H2O)3(OH)3 + 3CO2 + 3H2O
[M(H2O)6]2+ with CO3^2-
[M(H2O)6]2+ + CO3^2- –> MCO3 + 6H2O
reactions of Al(H2O)3(OH)3 with acid and base
Al(H2O)3(OH)3 + H+ –> [Al(H2O)6]3+
Al(H2O)3(OH)3 + OH- –> [Al(OH)4]- + 3H2O
[M(H2O)6]2+ with H2O
[M(H2O)6]3+ + H2O –>
[M(OH)(H2O)5]+ + H3O+
[M(H2O)6]3+ + H2O
[M(H2O)6]3+ + H2O –>
[M(OH)(H2O)5]2+ + H3O+
