AQA - Unit 5 - Energetics, Redox and Inorganic Chemistry

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Something about why is Copper(II) ions blue?

I said the d subshell splits when ligands attach, forming levels of different energy. The electrons in it require energy = delta E to make the jump to higher energy level. They get this energy by absorbing light, in copper then absorb red light, and reflect the rest, because red is absorbed this mean blue gets reflected and is visible at this colour :smile:

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Not 100% about my physicsy stuff but it's along those lines :tongue:

i wrote blue is absorbed lol but the rest looks similar

Reply 1401

al_habib

Original post by Betsss

For why copper (II) ions are blue, i put:
- Cu2+ is a transition metal ion, so it has an incomplete d-sublevel
- it can undergo d-to-d transitions
- the electrons absorb light, which excites them to a higher energy level
- they then emit light to fall back to ground state
- Cu2+ ions absorb red light from the visible spectrum; so they will appear the complementary colour (blue)

Is this ok, this was the section i was least confident with :frown:

and it had to come up!!

wow thats full mark!

Reply 1402

king101

Original post by al_habib

wow thats full mark!

Was just a standard 'Learn this' question :biggrin:

How does everyone else feel about the exam?

Reply 1403

happi_minnie

what did everyone get for the enthalpy of the 2 mol of NH3?
Also NO POINT IN LERANING ALL THE COLOURS! absolute waste of time

Reply 1404

king101

Agreed on the pointlessness of learning colors, although there was a fair amount of applying what you learn from equations on the paper

Reply 1405

happi_minnie

Original post by Zakir

what were the two shapes that the palladium complex could have and the coordination number?

i put tetrahedral and square planar.... but i could be wrong.. :/

Reply 1406

lou12

what did people put for the ionic equation for Al203 and Hcl. i just wrote the full equation, as i didn't think it could be simplified

Reply 1407

king101

Original post by happi_minnie

i put tetrahedral and square planar.... but i could be wrong.. :/

That looks about right, they are the only ones a 4 bonded species.

Reply 1408

king101

Original post by lou12

what did people put for the ionic equation for Al203 and Hcl. i just wrote the full equation, as i didn't think it could be simplified

I don't think it did simplify, was another "Just Learn" question.

Reply 1409

User544981

how did everyone find the exam
i thought it was k but hated the deltaE=hv question cos i didnt learn it as i was least confident with that section
and wtf no colours well only 2 marks and i wasted my time learning them all
overall im k with the paper but some people in my class found it hard
and i liked the two questions on entropy and the question on periodicity
my predicted grade boundaries will be same as jan 2011 grade boundaries i think but it also depends on how other people did

Reply 1410

-jessica

What did people get for the percentage in the last question?

Reply 1411

User544981

Original post by happi_minnie

what did everyone get for the enthalpy of the 2 mol of NH3?
Also NO POINT IN LERANING ALL THE COLOURS! absolute waste of time

i got +38 i think cant remember it was a bit of a trick question cos it sed one mole of ammonia but it showed 2 moles in the question

Reply 1412

Betsss

Original post by king101

I don't think it did simplify, was another "Just Learn" question.

I did Al3+ + 4OH- -> [Al(OH)4]-
because the Na and water were spectator ions?

Reply 1413

User544981

Original post by -jessica

What did people get for the percentage in the last question?

i think my answer was 53.6 or 58.3 percent cant remember hoping someone else got one of these answers too

Reply 1414

happi_minnie

Original post by -jessica

What did people get for the percentage in the last question?

i got something like 53.7%

Reply 1415

king101

Original post by -jessica

What did people get for the percentage in the last question?

Something in the range of 53.7, cannot really remember.

Reply 1416

User544981

for the ligand question was the answer hydrogen because it doesnt have a lone pair of electrons it cud donate

and also for the redox what was the answer to 5f where there were 2 graphs