Complex Ions

Question 1

What colour is Vanadium 5?

Answer 1

Yellow

Question 2

what colour is vanadium 4?

Answer 2

Blue

Question 3

What colour is vanadium 3?

Answer 3

Green

Question 4

What colour is vanadium 2?

Answer 4

Purple

Question 5

What is a metal Aqua ion?

Answer 5

Complex ion that only contains water ligands

Question 6

Describe the charge of a metal aqua ion

Answer 6

-Neutral charge
-Charge is determined by metal centre

Question 7

State the colour of Hexaaquairon II and its formula

Answer 7

Green

[Fe(H2O)6]^2+

Question 8

State the colour of Hexaaquacopper II and its formula

Answer 8

Blue

[Cu(H2O)6]^2+

Question 9

State the colour of Hexaaquairon III and its formula

Answer 9

Yellow

[Fe(H2O)6]^3+

Question 10

State the colour of Hexaaquaaluminium III and its formula

Answer 10

Colourless

[Al(H2O)6]^3+

Question 11

Colour change: iron II with NaOH

Answer 11

Green ppt

Question 12

Colour change: Copper II with NaOH

Answer 12

Blue ppt

Question 13

Colour change: iron III with NaOH

Answer 13

Brown ppt

Question 14

Colour change: aluminium III with NaOH

Answer 14

White ppt

Question 15

What happens if the green ppt formed when iron II is with NaOH is exposed to air?

Answer 15

Goes brown

Question 16

Which is the only metal to react with excess NaOH and what is the colour change?

Answer 16

Aluminium III

White ppt dissolves-> colourless solution

Question 17

What is the name for something that can react with acids and bases?

Answer 17

Amphoteric

Question 18

What colours do the metals go when Ammonia is added?

Answer 18

Same as with NaOH:

Iron II: green ppt
Copper II: blue ppt
Iron III: brown ppt
Aluminium III: white ppt

Question 19

What colour do the metals go when excess ammonia is added?

Answer 19

All stay the same apart from copper II:

Blue ppt dissolves-> forms a deep blue solution

Question 20

Colour change: iron II with Na2CO3

Answer 20

Green ppt

no bubbles

metal carbonate formed: FeCO3

Question 21

Colour change: copper II with Na2CO3

Answer 21

Blue-green ppt

no bubbles

metal carbonate formed: CuCO3

Question 22

Colour change: Iron III with Na2CO3

Answer 22

Brown ppt

Bubbles of CO2 gas

Question 23

Colour change: Aluminium III with Na2CO3

Answer 23

White ppt

Bubbles of CO2 gas

Question 24

Why are 3+ metal aqua ions stronger acids than 2+, but form a lower pH?

Answer 24

• 3+ have a higher nuclear charge, so more attraction of its electrons making it a smaller ion
• 3+ will have a higher charge/ size ratio
• Smaller ions are more acidic metal aqua ions

Question 25

What charge do precipitates have?

Answer 25

Neutral

Question 26

Use an equation to show how metal aqua ions can act as an acid in water (use copper II as an example)

Answer 26

[Cu(H2O)6]^2+ + H2O. --> [Cu(OH)(H2O)5]^+ +. H3O^+ the complex ion releases a H+ *this is an equilibrium

Question 27

When NaOH is added, what does it act as?

Answer 27

Splits into Na+ and OH- OH- now acts as a base and will remove a H+ from a metal aqua ion

Question 28

Give an example equation of the reaction between NaOH and iron II

Answer 28

[Fe(H2O)6]^2+. +. 2OH- -->. Fe(OH)2(H2O)4. + 2H2O Takes 2 H+

Question 29

Give an example equation for the reaction of Aluminium III with NaOH

Answer 29

[Al(H2O)6]^3+ +. 3OH- -->. Al(OH)3(H2O)3. + 3H2O Takes 3 H+

Question 30

Give an example reaction of aluminium III with ammonia

Answer 30

(same as with NaOH) [Al(H2O)6]^3+ +. 3NH3. --->. Al(OH)3(H2O)3. + 3NH4+ Takes 3 H+

Question 31

Give the equation for when Cu(OH)2(H2O)4 reacts with excess ammonia

Answer 31

Cu(OH)2(H2O)4. + 4NH3 --> [Cu(NH3)4(H2O)2]^2+. + 2OH- + 2H2O a ligand substitution reaction

Question 32

Give an example of an equation for iron III with Na2CO3

Answer 32

2[Fe(H2O)6]^3+. + 3CO3^2- --> 2Fe(H2O)3(OH)3. + 3CO2. + 3H2O

Question 33

Give an example equation for copper II with Na2CO3

Answer 33

[Cu(H2O)6]^2+. + CO3^2- --> CuCO3 +. 6H2O