Topic 15- Transition metals

Question 1

What colour is produced when copper ions react with HCL?

Answer 1

Yellow solution

Question 2

What is meant by the coordination number?

Answer 2

number of dative bonds in a complex

Question 3

What colour precipitate is Iron(II) Hydroxide?

Answer 3

Green precipitate

Question 4

What is the colour of solution of Hexaquacobalt(II)

Answer 4

Pink solution

Question 5

Colour of tetraaminediaquacopper(II)

Answer 5

Dark Blue solution

Question 6

What colour precipitate is Iron(III) hydroxide

Answer 6

Brown precipitate

Question 7

Colour of V2+

Answer 7

purple

Question 8

Colour of V3+

Answer 8

green

Question 9

Colour of VO 2+

Answer 9

blue

Question 10

What is meant by a Ligand?

Answer 10

a species which uses lone pair of electrons to form a dative bond with a metal ion

Question 11

3 steps of Catalytic converters

Answer 11

-adsorption of CO and NO molecules onto the surface of the catalyst
-weakening of bonds and chemical reaction
-desorption of CO2 and N2 product molecules from the surface of the catalyst

Question 12

Properties of transition metals

Answer 12

Have variable oxidation states
Good catalysts
Form coloured ions in solutions

Question 13

Why do transition metals have variable oxidation states?

Answer 13

The outer electrons sit in the 4s and 3d sub shells which are very close in energy levels

Question 14

Why is Scandium not a transition metal?

Answer 14

Forms Sc3+ ion only has one stable ion
Has an empty d-subshell

Question 15

Why is zinc not a transition metal?

Answer 15

The Zn2+ ion forms a full d-subshell

Question 16

Examples of bidentate ligands

Answer 16

Ethanedioate (C2O4 2-)
Ethane-1,2-diamine (NH2CH2CH2NH2)

Question 17

Examples of multi dentate ligands

Answer 17

EDTA4- can form 6 bonds (coordination number of 6)

Question 18

Haemoglobin shape

Answer 18

Octahedral

Question 19

What can haemoglobin carry and replace the ligand with

Answer 19

Can replace H2O with O2 to form oxyhaemoglobin
Can also bond to carbon monoxide- harder to replace ligand because has a very strong bond

Question 20

Square planar examples

Answer 20

Cis-Platin and Trans-platin (90 degrees)

Question 21

When does the d-orbital split

Answer 21

When ligands begin to attach to the central metal ion

Question 22

Why do colours show

Answer 22

When white light is absorbed from electrons in the ground state they become excited and move further up to their excited state. Drop back down to ground level releasing visible light on electromagnetic spectrum

Question 23

What is colour dependent on?

Answer 23

The central metal ion
The type of ligand
The shape of the ligand

Question 24

What do redox potentials tell us about transition metals?

Answer 24

Tells us how easy a complex is reduced

Question 25

What is meant if a transition metal has a larger Ecell value?

Answer 25

It is unstable

Question 26

Why are zinc ions colourless?

Answer 26

They have a full d-subshell and therefore electrons cannot be promoted

Question 27

Equation for reaction between amphoteric chromium hydroxide with base (OH-)

Answer 27

Cr(H2O)3(OH)3 + 3OH- --> [Cr(OH)6]3+ +3H2O

Question 28

Equation for reaction between amphoteric chromium hydroxide and acid (H+)

Answer 28

Cr(H2O)3(OH)3 + 3H+ --> [Cr(H2O)6]3+ +3H2O

Question 29

Reaction between iodine and thiosulfate ions

Answer 29

2S2O3(2-) + I2 --> 2I- + S4O6(2-)

Question 30

what colour is the [Co(Η2Ο)6]2+ ion

Answer 30

pink solution

Question 31

what colour is the [CoCl4]2− ion

Answer 31

blue in solution

Question 32

How V2O5 acts as a catalyst in the contact process

Answer 32

V 2 O 5 is used as a catalyst to reduce the higher temperature requirements and it increases the rate of reaction as well

Question 33

colour of Cr2O7 2- (dichromate)

Answer 33

orange

Question 34

colour of CrO4 2- (chromate)

Answer 34

yellow

Question 35

colour of Cr3+

Answer 35

green

Question 36

colour of Cr2+

Answer 36

blue

Question 37

equilibrium reaction between chromate(VI) and dichromate(VI)

Answer 37

Cr2O7 2- + OH- <--> CrO4 2- + H+

Question 38

Addition of acid to reaction between dichromate and chromate equilibrium

Answer 38

Will shift to the left, produce more dichromate

Question 39

Addition of alkali to reaction between dichromate and chromate equilibrium

Answer 39

Will shift yo the right, produce more chromate ions