Unit 3.5.4 - Transition Metals Flashcards
What catalyst is used in the haber process?
Iron
Name three unidentate ligands.
Ammonia, chloride ions and water
What formal can be used to find the amount of energy absorbed when electrons jump between states in the d subshell?
∆E = hv
What is the shape and bond angle for complex ions with the coordination number of 4?
Tetrahedral - 109.5
What is the equation for what is happening in catalytic converters?
2CO + 2NO → 2CO₂ + N
Draw what [Cu(Cl)4]2- looks like.
What do you have to produce before you can do spectrometry to find the concentration of a complex ion in a solution? And how? And Why?
A calibration graph - by measuring absorbances of known concentrations of solution and plotting a graph - so you can measure the absorbance of the sample off the graph to find its concentraion
Why is there two energy levels within the 3d subshell in complex ions?
When a ligand bonds to the metal ion some orbitals are give more than others splitting the energy level in two
Draw what Tollen’s reagent looks like.
What is the lowest energy level within the 3d subshell called?
Ground state
What is meant by coordination number?
The number of coordinate bonds that are formed with the central metal ions
What is the intermediate species in between S₂O₈²⁻ and I⁻ ?
Fe³⁺
What is the intermediate species in the reaction between MnO₄⁻ and C₂O₄²⁻?
Mn³⁺
Name two ways you can maximise the efficiency and minimise the costs of an expensive catalyst.
1.) increase their surface area 2.) remove catalyst poisons from the reactants
What colour is [Co(H₂O)₄(OH)₂]?
Blue precipitate
What is the general equation for the reaction between an aldehyde and Tollen’s reagent?
RCHO + 2[Ag(NH₃)₂]⁺ 3OH⁻ → RCOO⁻ + 2Ag + 4NH₃ + 2H₂O
What colour is the Cr²⁺ ion?
Blue
What is a complex ion?
A metal ion surrounded by co-ordinately bonded ligands
What is a unidentate ligand?
Ligands that only form one coordinate bond
What colour is the CrO₄²⁻ ion?
Yellow
What is haemoglobin called when it has an oxygen ligand?
Oxyhaemoglobin
Name a biological complex ion.
Haemoglobin
What is the vanadium ion with the oxidation state +3?
V³⁺
Draw what 1,2-diaminoethane looks like.
Why are transition metals far to the right of period 5 and 6 not good catalysts?
They absorb reactants too weakly
What is the usual coordination number when metal ions are bonded to smaller ligands?
6
What do aldehydes and ketones produced when reacted with Tollen’s reagent?
Aldehydes - silver mirror Ketones - no visible change
What can poison the catalyst in the haber process?
Sulphur
What catalyst is use during the manufacturing of methanol?
Chromium (III) oxide - Cr₂O₃
What happens if you add H⁺ ions to this reaction : Cr₂O₇²⁻ + H₂O ⇋ 2CrO₄²⁻ + 2H⁺ ?
The increased concentration of H⁺ ions moves the position of equilibrium to the left producing more Cr₂O₇²⁻ ions
What is catalyst poisoning?
Where impurities bind to the catalysts surface and block reactants from being absorbed
What does h and v stand for in: ∆E = hv?
v - frequency of light absorbed in Hz h - planck’s constant
Name a multidentate ligand and how many bonds it forms.
EDTA⁴⁻ - it forms 6 bonds
When oxidised Co²⁺ to Co³⁺ why is the method of using ammonia used more often?
It is easier to oxidised [Co(NH₃)₆]²⁺ than [Co(H₂O)₆]²⁺
What colour is the Fe³⁺ ion?
Yellow
What is the initial equation for what is happening when MnO₄⁻ reacts with C₂O₄²⁻ ?
2MnO₄⁻ + 16H⁺ + 5C₂O₄²⁻→ 2Mn²⁺ + 8H₂O + 10CO₂
What colour is the end point of the titration between Fe²⁺ and MnO₄⁻?
Purple
What is the equation for the titration off Fe²⁺ against MnO₄⁻?
MnO₄⁻ + 8H⁺ + 5Fe²⁺→ Mn²⁺ + 4H₂O + 5Fe³⁺
What is the overall equation for what methanol is manufacture from carbon monoxide and hydrogen?
CO + 2H₂ → CH₃OH
What can you use spectrometry of a solution containing a complex ion to find?
The concentration of the solution
Why does a reaction speed up increasing if autocatalysis is taking place?
As the reaction progresses the amount of product increases there is more catalyst and so the reaction speeds up over time
How does haemoglobin transport oxygen around the body?
In the lungs where oxygen concentration is high its water ligand is substituted for an oxygen ligand In the respiring cells where the oxygen concentration is low its oxygen ligand is substituted for a water ligand
Why are transition metals far to the left of period 5 and 6 not good catalysts?
They absorb the reactants too strongly
How do homogeneous catalysts work in two steps?
1.) The reactant combines with the catalyst to form an intermediate species 2.) The intermediate species than reacts with the other reactants to form the products and catalyst faster than the original reactants would off
How can you turn Cr₂O₇²⁻ into CrO₄²⁻ ions?
Putting it into alkali solution - OH⁻ ions
What are the there steps to change [Co(H₂O)₆]²⁺ to [Co(NH₃)₆]³⁺?
1.) add a small amount of NH₃ to the solution to form [Co(H₂O)₄(OH)₂] 2.) add excess NH₃ to the solution to form [Co(NH₃)₆]²⁺ 3.) leave to stand in air so it is oxidised to [Co(NH₃)₆]³⁺
What is the colour change in this reaction: 2Cr³⁺ + 10OH⁻ + 3H₂O₂ → 2CrO₄²⁻ + 8H₂O?
Green to Yellow
What is the overall reaction for what is happening during the contact process?
SO₂ + 1/2O₂ → SO₃
Name a silver complex with the shape linear. And give its common name.
[Ag(NH₃)₂]⁺ - Tollen’s reagent
Draw what [Fe(H2O)6]2+ looks like.
What is cisplatin? And what does it look like?
A platinium (II) complex, it has two ammonia ligands and two chloride ligands
What does a haemoglobin complex ion look like?
A central Fe²⁺ ions which is hexa-coordinated to four nitrogen atoms, a global molecule and either an oxygen or water molecule
Why doesn’t chromium follow the usual rules for electronic configuration?
Chromium prefers to have one electron in each orbital of the 3d subshell and just one in the 4s subshell
Why is cisplatin used as an anticancer drug?
It forms coordinate bonds with nitrogen atoms in the DNA, preventing it from unwinding and so replicating, meaning the cancer cells can’t replicate
What is the usual coordination number when metal ions are bonded to larger ligands?
4
What are the two types of catalysts?
Heterogeneous and homogenous
How do you form Cr³⁺ from Cr₂O₇²⁻ ions?
Cr₂O₇²⁻ is reduced by Zn in acidic conditions
Where is the d block in the periodic table? And what type of elements make it up?
The middle - Transition metals
Name four processes where heterogeneous catalysts are use.
Catalytic converters, contact process, manufacturing of methanol and the haber process
What is the highest energy level within the 3d subshell called?
Excited state
What is the vanadium ion with the oxidation state +2?
V²⁺
What is autocatalysis?
Where the products of the recantation catalyse the reaction
What is a downside to cisplatin?
It prevents normal cells like blood and hair cells from replicating
Why do some transition metals have variable oxidation states?
The energy levels of 4s and 3d subshells are very close together so different number of electrons can be lost using a fairly similar amount of energy
What is the overall equation for reaction between S₂O₈²⁻ and I⁻ ions?
S₂O₈²⁻ + 2I⁻→ I₂ + 2SO₄²⁻
What colour is the Cr³⁺ ion?
Violet
What is multidentate ligand?
Ligands that form more than two coordinate bonds
Draw what EDTA4- looks like
What is the shape and bond angle for complex ions with the coordination number of 2?
Linear - 180
What is a catalyst?
Something that speeds up the rate of reaction without being used up or changed
What is the contact process used to make?
Sulphuric acid
Which electrons are removed first when transition metals become positive ions?
S and then d
What is the manganese ion with the oxidation state +2?
Mn²⁺
What is the colour of the V²⁺ ion?
Violet
How do you form Cr²⁺ ions from Cr³⁺ ions?
Cr³⁺ is reduced by Zn in acidic conditions
What is the vanadium ion with the oxidation state +4?
VO²⁺
What are the two equations in the reaction between S₂O₈²⁻ and I⁻ ions when there is an Fe²⁺ catalyst?
1.) S₂O₈²⁻ + 2Fe²⁺ → 2Fe³⁺ + 2SO₄²⁻ 2.) 2Fe³⁺ + 2I⁻ → I₂ + 2Fe²⁺