TRANSITION METALS

Question 1

TRANSITION METALS

Answer 1

Forms at least one stable ion with a partially filled D-sub shell

Question 2

What are the 2 exseption ?

Answer 2

Sc- 1s2 2s2 2p6 3s2 3p6 4s2 3d1
Zn- 1s2 2s2 2p6 3s2 3p6 4s2 3d10

Question 3

Key features of transition metals

Answer 3

Complex ion
Coloured ion
Catalytic properties
Variable oxidation state

Question 4

What is a coordinate bond

Answer 4

Shared pair of e- which both come from same atom

Question 5

Ligand definition

Answer 5

Ion or molecule eith a lone pair of e- which can form a coordinate bond with a transtiom metal ion

Question 6

Coordinate number definition

Answer 6

Number kf coordinate bonds a transition metals ions forms

Question 7

Complex ion definition

Answer 7

Transition metals ions form surrounded by ligands

Question 8

Monodentate ligands example

Answer 8

H2O:
-:CN
:NH3
-:OH
CL:-

Question 9

Bidentandate ligands example

Answer 9

1,2-diaminoethane
Ethanedioate ion

Question 10

How many bond does EDTA4- form

Answer 10

6

Question 11

What is the chellate effect

Answer 11

Occurs when a monidentate ligand substituetes by bidentate
If there is an increase in moles on the products side
Entropy AS decreases as more disorder
So reaction is feasible

Question 12

How does HB work

Answer 12

O2 forms a coordinate bond to Fe2+ in haemoglobin enabling oxygen to be transported in the blood
CO toxic because CO bind more strongly to the Fe2+ in haemoglobin this orevents oxygen from bonding to Fe2+ causing soffication

Question 13

Difference between cis/trans

Answer 13

Trans- 180 degrees between ligands
Cus - 90 degrees between ligands

Question 14

How does plactin works

Answer 14

Binds to DNA in cancerous cells
Stops cell replication
Preventing DNA. From unwinding so cancerous cells cant replicate which prevents spreading of cancerous celks

Question 15

Rormation of coloured ions

Answer 15

Due to patrtially filled d sub-shell absirb some of the colours from white light and reflects other
ROY- low energy
BIV- high energy

Question 16

Why are some complexes colourless

Answer 16

No e- in d shell
/
Full d-sub shell

Question 17

What causes alterstion of a compund colour

Answer 17

Change in ligands
Changd in oxidation state
Change in shape
Change in coordination number

Question 18

How to find concentration of unkown sample form calibration curve

Answer 18

Measure absorbance for a range of known concentration
Plot a graph of concentration against absorbance/transmission
Read value of the concentration for measured absorbance from graph

Question 19

What is a catalyst ?

Answer 19

Substance increases rate of reaction of a chemical reaction without being used up

Question 20

How do catalust work?

Answer 20

Provides an alternative pathway with lower activation energy

Question 21

Heterogeneous catalyst

Answer 21

Catalyst is in a different phase to the reactants

Question 22

Homogeneous catalyst

Answer 22

Catalyst in same phase to the reactant

Question 23

How xo heterogenous catalyst work

Answer 23

Reactant adsorb onto surface if catalust on active site
Reaction occurs on surface of catalyst
Products desorb form surface of catalyst

Question 24

How to make catalyst more efficient? (2)

Answer 24

Increase surface area
Spread catalust over aninert support medium

Question 25

Why dont catalyst last forever?

Answer 25

Immpurities can blocj active sites Prevents reactants from adsorbing Purifying reactants in the best way to prevent poisoning

Question 26

Why is rate slow initially

Answer 26

No catalyst initially 2 negatively charged reactants collide with very high Ea As reactant that act as catalyst formed rate increases as reaction is being increasingly catalysed Rare then decreases and levels off as reactant get used up

Question 27

Small E ROY ABS

Answer 27

Small AE between d sub shell Low energy light Will be absorbed to excite the e- Blue indingo purple will be reflected

Question 28

Big E BIV abs

Answer 28

Large AE between d subshell High energy lost Will bd absorbed to excite e- Red yellow oranfe will be reflected

Question 29

Harber process Equations + catalyst

Answer 29

Catalyst: iron N2(g) +3H2(g) <———> 2NH3(g)

Question 30

Contact process Equation + catalyst

Answer 30

Catalyst: V2O5 SO2(g) + V2O5(s) <——-> SO3(g) + V2O4(s) 2V2O4(s) +O2(g) <———-> 2V2O5(g) Overall equation 2SO2(g) +O2(g) ————> 2SO3(g)

Question 31

Manufucture of methanol Catalust + equation

Answer 31

CH4(g) + H2O(g) ———-> CO(g)+ 3H2(g) Catalyst: Cr2O3 CO(g) + 2H2(g) ———-> CH3OH(g)

Question 32

uncatalyzed reaction Catalyst + equation

Answer 32

2MnO4-(aq) + 16H+(aq) + 5C2O42-(aq) → 2Mn2+(aq) + 8H2O(l) + 10CO2(g) Catalyst Mn2+ 4Mn2+(aq) + MnO4-(aq) + 8H+(aq) → 5Mn3+(aq) + 4H2O(l) 2Mn3+(aq) + C2O4 2-(aq) ——> 2CO2 + 2Mn2+

Question 33

Homogeneous catalyst

Answer 33

S2O82-(aq) + 2I-(aq)→2SO42-(aq) + I2(aq) Catalyst:Fe2+ S2O82-(aq) + 2Fe2+(aq)→2SO42-(aq) + 2Fe3+(aq) 2I-(aq) + 2Fe3+(aq)→I2(aq) + 2Fe2+(aq)