transition metal Flashcards
1
Q
VO2+ (+5)
A
Yellow
2
Q
VO 2+ (+4)
A
Blue
3
Q
V3+
A
green
4
Q
V2+
A
violet
5
Q
cobalt
A
cobaltate
6
Q
aluminium
A
aluminate
7
Q
chromium
A
chromate
8
Q
vanadium
A
vanadate
9
Q
copper
A
cuprate
10
Q
iron
A
ferrate
11
Q
excess NH3
A
copper
chromium
cobalt
dissolve with excess NH3
12
Q
hexaaquacopper(II)ion + conc HCl
A
blue –> yellow [CuCl4]2- + 6H2O (l)
colour appears green
13
Q
Cu(H2O)4(OH)2 ppt
A
pale blue (Dropwise NH3/OH-)
14
Q
[Cu(NH3)4 (H2O)2]2+
A
deep blue solution (excess ammonia)
15
Q
Cr(OH)3 (H2O)3 ppt
A
green ppt (dropwise NH3/OH-)
16
Q
[Cr(NH3)6]3+
A
Purple solution
17
Q
Co(H2O)4(OH)2 ppt
A
blue ppt
18
Q
[Co(NH3)6]2+
A
pale brown solution that eventually darkens
19
Q
[Co(H2O)6]2+
A
PINK
20
Q
[Fe(H20)6] 2+
A
PALE GREEN
21
Q
[Fe(H2O)6]3+
A
YELLOW
22
Q
Fe(H2O)4(OH)2
A
green ppt with dropwise NaOH/NH3
23
Q
Fe(H2O)3(OH)3
A
browny-red ppt with dropwise NaOH/NH3
24
Q
[Cr(H2O)6]3+
A
GREEN
25
Cr(H2O)3(OH)3
Green ppt
26
[Cr(OH)6]3-
Dark green solution
27
what is the only tm ion that dissolves in excess hydroxide ions
chromium
28
amphoteric hydroxide/ion
acting both as an acid/base therefore can dissolve in either acid/alkali
29
How many oxidation states can does chromium have?
+2 +3 +6
30
what conditions are needed to oxidise chromium 3+ ions to chromate ions? (cro4 2-)
alkaline + H2O2
31
CrO4 2-
yellow
32
reduction of H2O2 --> 2OH-
H2O2 + 2H+ + 2e- --> 2OH-
33
oxidation of Cr3+ --> CrO4 2-
Cr 3+ + 8OH- ---> CrO4 2- + 4H2O + 3e-
34
What conditions are needed to reduce Cr 3+ --> Cr2+
zn using acidic condtions
35
oxidation of zn
zn --> zn2+ + 2e-
36
reduction of Cr3+
cr3+ + e- --> cr2+
37
what conditions are needed as well as zn and acid and explain why?
anaerobic conditions
| because zn2+ are very powerful reducing agents which are therefore rapidly oxidised back to cr3+ by oxygen
38
cr2+
blue-violet
39
what does chromium's colour in the +6 state rely on?
2CrO4 2- + 2H+ ---> Cr2O7 2- + H2O
40
Kstab
equilibrium constant for a TM ligand substitution
41
[CoCl4] 2-
blue
42
haber process
Fe (s)
43
hydrogenation
Ni
44
contact process
V2O5
45
Reforming
Pt
46
desorption
molecules/ions released from solid surface
47
adsorption
molecules/ions are held onto the surface of a solid
