Transition metals

Question 1

What are the properties of transition elements that are typical of all metals?

Answer 1

1. They have high melting points
2. They have high densities
3. They are hard and rigid, and so are useful as construction materials.
4. They are good conductors of electricity and heat.

Question 2

How do the physical properties of calcium compare to the physical properties of a transition element?

Answer 2

Melting point - Calcium is lower
Density - Calcium is lower
Atomic radius - Calcium is larger
Ionic radius - Calcium is larger
First ionization energy - Calcium is lower
Electrical conductivity - Calcium is higher

Question 3

Colour change in the reduction of Iron?

Answer 3

Fe3+(aq) + e -> Fe2+

Pale yellow -> Pale green

Question 4

Colour Change in the Reduction of MnO4-?

Answer 4

MnO4-(aq) + 8H+ +5e -> Mn2+(aq) + 4H2O(l)

Purple -> Pale pink

Question 5

Why is potassium dichromate preferred over manganate for iron titration?

Answer 5

it can be prepared for a higher degree of purity

Question 6

The reaction and colour change of adding OH- ions to the copper solution?

Answer 6

[Cu(H2O)6]2+(aq) + 2OH-(aq) -> Cu(OH)2(H2O)4(s) + 2H2O(l)

blue solution -> pale blue precipitate

Question 7

Adding concentrated ammonia to Cu(OH)2(H2O)4(s

Answer 7

Cu(OH)2(H2O)4(s) + 4NH3(aq) -> [Cu(H2O)2(NH3)4]2+(aq) + 2H2O(l) + 2Oh-(aq)
Pale blue precipitate -> deep blue solution

Question 8

The reaction of copper solution with HCl

Colour?

Answer 8

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

Yellow solution

Question 9

Colour of cobalt solution?

Answer 9

[Co(H2O)6]2+ is pink colour

Question 10

Cobalt Solution

1. Adding sodium hydroxide solution
2. Warm with excess alkali.

Answer 10

Pink colour

1. blue precipitate of cobalt (II) hydroxide
2. Turns red

Question 11

Reaction of aqueous cobalt with NH3

Answer 11

[Co(H2O)6]2+(aq) + 6NH3 -> [Co(NH3)6]2+(aq) +6H2O (l)

Question 12

The addition of concentrated hydrochloric acid drop by drop to aqueous cobalt.

Answer 12

[Co(H2O)6]2+(aq) + 4Cl-(aq) -> [CoCl4]2- + 6H2O(l)

Pink solution -> Blue solution