24 reaction of aqueous ions

Question 1

define hydration enthalpy

Answer 1

the standard enthalpy change when one mole of gaseous ions is converted to one mole of aqueous ions

Question 2

when ions are hydrated what are positive ions attracted to?

Answer 2

slightly negative oxygen in water molecules

Question 3

when ions are hydrated what are negative ions attracted to?

Answer 3

slightly positive hydrogens in water molecules

Question 4

what is a complex ion?

Answer 4

central atom or ion surrounded by ligands

Question 5

what is a coordinate bond?

Answer 5

shared pair of electrons that have both come from the same atom

Question 6

define ligand

Answer 6

ion or molecule with a lone pair of electrons which can form a coordinate bond with a transition metal ion

Question 7

define coordination number

Answer 7

number of coordinate bonds a transition metal ion forms

Question 8

what are 4 hexa aqua complex ions?

Answer 8

[Cu(H2O)6]2+
[Fe(H2O)6]2+
[Fe(H2O)6]3+
[Al(H2O)6]3+

Question 9

what is each hexa aqua complex ion’s colour?

Answer 9

[Cu(H2O)6]2+ = blue solution
[Fe(H2O)6]2+ = pale green solution
[Fe(H2O)6]3+ = yellow brown solution
[Al(H2O)6]3+ = colourless solution

Question 10

what colour is [Cu(H2O)6]2+?

Answer 10

blue solution

Question 11

what colour is [Fe(H2O)6]2+?

Answer 11

pale green solution

Question 12

what colour is [Fe(H2O)6]3+?

Answer 12

yellow brown solution

Question 13

what colour is [Al(H2O)6]3+

Answer 13

colourless solution

Question 14

which hexa aqua complex ions are more acidic?

Answer 14

3+ ions

Question 15

why are the 3+ ions more acidic?

Answer 15

smaller with higher charge
more polarising
attracts lone pair in O
weakens O-H
can release H+ more easily

Question 16

write an equation to show [Fe(H2O)6]3+ acting as an acid

Answer 16

[Fe(H2O)6]3+ -> [Fe(H2O)5(OH)]2+ + H+

Question 17

what 3 things do all the hexa aqua complex ions react with?

Answer 17

Na2CO3
NaOH
NH3

Question 18

how does [Fe(H2O6)]2+ react with Na2CO3?
state the observation

Answer 18

[Fe(H2O)6]2+ + CO3 2- -> FeCO3 (s) + 6H2O
green solution -> green precipitate

Question 19

how does [Fe(H2O6)]2+ react with NaOH?
state the observation

Answer 19

[Fe(H2O6)]2+ + 2OH- -> [Fe(H2O)4(OH)2] (s)+ 2H2O
green solution -> green precipitate

Question 20

how does [Fe(H2O6)]2+ react with NH3?
state the observation

Answer 20

[Fe(H2O6)]2+ + 2NH3 -> [Fe(H2O)4(OH)2] (s) + 2NH4+
green solution -> green precipitate

Question 21

how does [Cu(H2O)6]2+ react with Na2CO3?
state the observation

Answer 21

[Cu(H2O)]2+ + CO3 2- -> CuCO3 (s) + 6H2O
blue solution -> blue green precipitate

Question 22

how does [Cu(H2O)6]2+ react with NaOH?
state the observation

Answer 22

[Cu(H2O)6]2+ + 2OH- -> [Cu(H2O)4(OH)2] (s) + 2H2O
blue solution -> blue precipitate

Question 23

how does [Cu(H2O)6]2+ react with NH3?
state the observation

Answer 23

[Cu(H2O)6]2+ + 2NH3 -> [Cu(H2O)4(OH)2] (s) + 2NH4+
blue solution -> blue precipitate

Question 24

what other equation can also happen after [Cu(H2O)6] has reacted with 2NH3?

Answer 24

can react with an excess of ammonia

Question 25

how does [Cu(H2O)4(OH)2] react with an excess of ammonia? state the observation

Answer 25

[Cu(H2O)4(OH)2] + 2NH3 -> [Cu(H2O)2(NH3)4]2+ + 2H2O + 2OH- blue precipitate -> deep blue solution

Question 26

how does [Fe(H2O)6]3+ react with Na2CO3? state the observation

Answer 26

[Fe(H2O)6]3+ + 3CO3 2- -> 2[Fe(H2O)3(OH)3] + 3CO2 + 3H2O yellow brown solution -> brown precipitate with effervescence

Question 27

how does [Fe(H2O)6]3+ react with NaOH? state the observation

Answer 27

[Fe(H2O)6]3+ + 3OH- -> [Fe(H2O)3(OH)3] + 3H2O yellow brown solution -> brown precipitate

Question 28

how does [Fe(H2O)6]3+ react with NH3? state the observation

Answer 28

[Fe(H2O)6]3+ + 3NH3 -> [Fe(H2O)3(OH)3] + 3NH4+ yellow brown solution -> brown precipitate

Question 29

how does [Al(H2O)6]3+ react with Na2CO3? state the observation

Answer 29

[Al(H2O)6]3+ + 3CO3 2- -> [Al(H2O)3(OH)3] + 3CO2 +3H2O colourless solution -> white precipitate with effervescence

Question 30

how does [Al(H2O)6]3+ react with NaOH? state the observation

Answer 30

[Al(H2O)6]3+ + 3OH- -> [Al(H2O)3(OH)3] + 3H2O colourless solution -> white precipitate

Question 31

how does [Al(H2O)6]3+ react with NH3? state the observation

Answer 31

[Al(H2O)6]3+ + 3NH3 -> [Al(H2O)3(OH)3] + 3NH4+ colourless solution -> white precipitate

Question 32

what other equation can happen after [Al(H2O)6]3+ reacts with NaOH?

Answer 32

can react with another NaOH

Question 33

how does [Al(H2O)3(OH)3] react with an another OH? state the observation

Answer 33

[Al(H2O)3(OH)3] + OH- -> [Al(H2O)2(OH)4]- + H2O white precipitate -> colourless solution

Question 34

what does amphoteric mean?

Answer 34

can act as an acid or a base

Question 35

show [Al(H2O)3(OH)3] acting as a base

Answer 35

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

Question 36

show [Al(H2O)3(OH)3] acting as an acid

Answer 36

[Al(H2O)3(OH)3] + OH- -> [Al(H2O)2(OH)4]- + H2O

Question 37

how does [Cu(H2O)6]2+ react with HCl? state the observation

Answer 37

[Cu(H2O)6]2+ + 4Cl- -> [CuCl4]2- + 6H2O blue solution -> yellow solution