Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chem > Redox and Transition Metals > Flashcards

Redox and Transition Metals Flashcards

1
Q

What is a transition element?

A

A d block element that can form at least one stable ion with a partially filled d subshell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the electron configuration of Cr and Cu?

A

Cr [Ar] 4s1 3d5

Cu [Ar] 4s1 3d10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are properties of the transition metals?

A

Form coloured ions, good catalysts, exist in variable oxidation states, form complex ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a mono, bi and multidentate ligand?

Name a example of each.

A

Monodentate ligands can only form one dative covalent bond e.g. NH3, Cl-, CN- H2O.

Bidentate ligands can form two dative covalent bonds e.g. ethane-1, 2-diamine (en).

multidentate ligands can form 2 or more dative covalent bonds e.g. EDTA4- (6 bonds).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the co-ordination number of a complex ion?

A

The number of dative covalent bonds that form around the central transition metal ion.

(6 = octahedral/4 =tetrahedral or square planar)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What types of complex ion show cis-trans isomerism?

A

Square planar complex ions with 2 pairs of ligands and octahedral complex ions with 4 ligands of one type and 2 ligands of another type.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What types of complex ion show optical isomerism?

A

Octahedral complex ions with 3 bidentate ligands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the formula and colour of a complex ion with Cr3+
a) with water
b) with OH-/NH3
c) with excess OH-
d) with excess NH3

A

a) [Cr(H2O)6]3+ green

b) [Cr(H2O)3(OH)3] grey - green ppt

c) [Cr(OH)6]3- dark green

d) [Cr(NH3)6]3+ purple

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the formula and colour of a complex ion with Fe2+
a) with water
b) with OH-/NH3

A

a) [Fe(H2O)6]2+ pale green

b) [Fe(H2O)4(OH)2] dark green ppt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the formula and colour of a complex ion with Fe3+
a) with water
b) with OH-/NH3

A

a) [Fe(H2O)6]3+ yellow

b) [Fe(H2O)3(OH)3] orange-brown ppt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the formula and colour of a complex ion with Mn2+
a) with water
b) with OH-/NH3

A

a) [Mn(H2O)6]2+ pale pink

b) [Mn(H2O)4(OH)2] pale brown/buff ppt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the formula and colour of a complex ion with Cu2+
a) with water
b) with OH-/NH3
c) with excess NH3

A

a) [Cu(H2O)6]2+ pale blue

b) [Cu(H2O)4(OH)2] pale blue ppt

c) [Cu(NH3)4(H2O)2]2+ dark blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does haemoglobin work?

A

Water and oxygen bond to Fe2+ as ligands.

In the lungs, water ligands are substituted for oxygen to form oxyhaemoglobin.

Oxyhaemoglobin can substitute oxygen for water at places where oxygen is needed.

Carbon monoxide forms a strong dative covalent bond with Fe2+ and oxygen cannot substitute carbon monoxide.

This is fatal because haemoglobin can no longer bond with oxygen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the equation for the ligand substitution of [Cr(H2O)6]3+ with NH3 (with colours and shape)

A

[Cr(H2O)6]3+ + 6NH3 –> [Cr(NH3)6]3+ + 6H2O

Pale purple (pale green visibly) –> purple Octahedral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the equation for the ligand substitution of [Cu(H2O)6]2+ with NH3 (with colours and shape)

A

[Cu(H2O)6]2+ + 4NH3 –> [Cu(NH3)4(H2O)2]2+ + 4H2O

Pale blue –> deep blue

Octahedral –> elongated octahedral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the equation for the ligand substitution of [Cu(H2O)6]2+ with Cl- (with colours and shape)

A

[Cu(H2O)6]2+ + 4Cl- –> [CuCl4]2- + 6H2O

Pale blue –> yellow - green

octahedral –> tetrahedral

17
Q

What is the equation for the reduction of manganate (VII) with iron (II) and what are the colour changes?

A

MnO4- + 8H+ + 5Fe2+ –> Mn2+ + 4H2O + 5Fe3+

pale green –> yellow

18
Q

What is the equation of the reduction of Fe3+ with iodide ions and what are the colour changes?

A

2Fe3+ + 2I- –> 2Fe2+ + I2

orange brown –> brown

19
Q

What is the equation for the oxidation of chromium with H2O2 and what is the colour change?

A

[Cr(OH)6]3- + 3H2O2 –> 2OH- + 2CrO4- + 8H2O

dark green –> yellow

20
Q

What is the oxidation of chromate (VI) with sulphuric acid and what is the colour change?

A

2CrO4- + 2H+ –> Cr2O72- + H2O

yellow –> orange

21
Q

What is equation for the reduction of dichromate ions with zinc and what is the colour change?

A

Cr2O72- + 14H+ + 3Zn –> 2Cr3+ + 7H2O + 3Zn2+

orange –> dark green

22
Q

What is the equation for the reduction of Cu2+ with iodide ions and what is the colour change?

A

2Cu2+ + 4I- –> 2CuI + I2

pale blue –> white ppt and brown

23
Q

What is a electrochemical cell?

A

Made from two different metals dipped in salt solutions of their own ions and connect by a wire and a salt bridge.

Each metal electrode dipped in solution is a half cell.

There will be a reduction reaction in one half cell and oxidation reaction in the other.

24
Q

How do you calculate the standard cell potential?

A

Standard electrode potential of the reduction half cell (the one that is most positive) - standard electrode potential of the oxidation half cell (the one that is most negative).

The cell will work if the cell potential is positive.

25
Q

What is the standard electrode potential value?

A

The voltage measured under standard conditions (concentrations 1 moldm-3, 298K and 100kPa) when the half cell is connected to a standard hydrogen electrode (0.00V)

26
Q

What are the advantages and disadvantages of electrochemical cells?

A

Cheap, high power densities/use of toxic chemicals that need to be disposed of when they reach the end of their life span, chemical used are flammable

27
Q

Explain what would happen if these two half cells were connected in an electrochemical cell (Cr3+ + 3e- <– –> Cr E = -0.77 Ag+ + e- <– –> Ag E = +0.80)

A

Cr system is more negative so will be the oxidation half cell.

Ag system is more positive so will be the reduction half cell.

Cr system shifts to the left and Ag system shifts to the right.

28
Q

Explain what would happen if these two half cells were connected in an electrochemical cell (Cu2+ + 2e- <– –> Cu E = +0.34 Zn2+ + 2e- <– –> Zn E = -0.76)

A

Zn system is more negative so will be the oxidation half cell.

Cu system is more positive so will be the reduction half cell.

Zn system shifts to the left and Cu system shifts to the right.

29
Q

What are the half equations and overall equations for an alkaline hydrogen fuel cell?

A

H2 + 2OH- –> 2H2O + 2e-

1/2O2 + H2O + 2e- –> 2OH-

30
Q

What are the half equations and overall equations for an acidic hydrogen fuel cell?

A

H2 –> 2H+ + 2e-

1/2O2 + 2H+ + 2e- –> H2O

Chem (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions