DM

Question 1

What is oxidised in a manganate (IV) titration?

Answer 1

Fe ions

Question 2

Equations in titration

Answer 2

MnO4- + 5e- + 8H+ –> Mn2+ + 4H2O

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

Question 3

Voltage equation

Answer 3

V = JC^-1

Question 4

Standard conditions for electrochemical cell

Answer 4

298K
1 moldm-3
1atm/10^5 Pa

Question 5

How to calculate e-cell

Answer 5

More positive - more negative

Question 6

What do electron potentials measure?

Answer 6

Tendency to accept electrons

Question 7

How do you know if an electrochemical cell reaction is feasible?

Answer 7

Ecell is positive in value

Question 8

Nail rusting experiment results

Answer 8

Air and water must be present for rusting
Phenolphthalein turns pink - OH- ions
Blue = Fe2+

Question 9

What is a transition metal?

Answer 9

D-block element
Forms one or more stable ions
Incomplete d-orbitals

Question 10

Which transition metals have a different arrangement and why?

Answer 10

Chromium and copper
4s orbital is full, and one of the s orbitals is empty/only has one electron

Instead of 2 in 4s, one moves to 3d to reduce repulsion in 4s orbital

Question 11

What is a ligand?

Answer 11

Ion or molecule that binds to a central metal atom/ion
Dative covalent bond

Question 12

Iron complexes

Answer 12

[Fe(H2O)6]2+
[Fe(H2O)6]3+ yellow-brown

Question 13

Copper complexes

Answer 13

[Cu(H2O)6]2+ = blue
[Cu(NH3)4]2+ = deep blue/violet
[CuCl4]2– = yellow

Question 14

Ethanedioate ion

Answer 14

2 x O=C
C-C
2 X C-O
2 x O-M

Question 15

Heterogeneous catalysis

Answer 15

Use 3d/4s electrons on metal surface to form weak bonds (chemisorption)

Question 16

Homogeneous catalysis

Answer 16

Forms intermediate
Several oxidation states