Chalter 24.4 Onwards Colour Memorisaition Etc Flashcards
INITAL [Cu (H2o)6 ] 2+ colour
How is it made
Thus js PALE BLUE
This is formed when copper SUKFATE is dissolved in excess ammonia
[Cu (H2O)6] 2+ with ammonia full colours and reactions
Start = pale blue
Adding dropwise ammonia = baby blue precipate of Cu(OH)2 s formed
Adding more = DARK blue solution of [Cu(Nh3)4(H2O)2]2+ formed finally
What happens is the copped hydroxide dissolved in excess ammonia ti form the new complex
Copper water complex with CHLORINE IONS?
what is the SOURCE OF THE CHLORINE IONS
1) colour with chlorine
2) colour if add water again?
3) why is a green colour observed half way through ?
Source = concentrated excess HYDROCHLORIC ACID
1) Adding 4 chlorine ions will make copper chloride with 2- complex which is PALE YELLOW
2) If you add water back, it’s reversible so ti will go back to pale blue, but more pale
3) half way through green intermediate as yellow and light blue mixed,
What happens with copper water and chlorine charge and shape of new comolex
After substation , as chlorine ions big, only 4 held = tetrahedral , and 4 cl- cancels charge to 2- too
What is the base colour for hexa aquar chromium 3+?
This is pale purple to begin with
What is the colour change and reaction when hexa Aqua chromium reacts with EXCESS AMMONIA
[Cr (H2O)6]3+ + 6NH3 = [Cr(NH3)6] 3+ + 6 H2O
VIOLET TO PURPLE
What happens in the reaction with hexa chromium and excess ammonia drops aide
Dropwise
1) intial,t a grey predicate of Cr (OH)3 made
2) then dissolves to make Chromium ammonia purple
Same thing for copper water and ammonia, first copper hydroxide blue, then copper ammonia water which is dark blue
What does haemobloin have allows for things to bind
Role of haemoglonin in the body for breathing in AND out
What happens if CARBIN monoxide breathed and what is problem
1) each harmogolobin molecule has 4 proteins attached that all have a haem group attached , which has an FE 2+ central ion which allows to bind to oxygen etc
2) role breathing in to bind with oxygen , role breathing out to bind with co2 to release
3) CO BINDS MUCH MORE readily to hamelglonin compared to oxygen, and is NON REVERSIBLE. A small conc of CO is enough to prevent oxygen transport and thus death. Odourless and no colour = killer
Hexa aqua copper (2) and chromium (1) reactions and colours
3 reactions in total
Hexa aqua copper = pale blue
React with 4 ammonia = Co(Oh2) (blue) and then copper 4 ammonia and 2 water = DARK BLUE
hexa aqua copper with 4 chlorine ions = PALE YELLOW tetrahedral chlorine
Reversible!! Becomes blue again with addition of water
Green intermediate when colours mix
Hexa aqua chromium + 6 ammonia = VIOLET TO PURPLE
What is a predication reaction
How we gonna see this in this topic?
When two aqeuous solutions containing ions react to form an INSOLUBLE SOLID = PRECIPATE
-> in this topic NaOH and Nh3 react with transition metal ion solutions to give precipated and then further dissolved to give compex ions again
4 ions soltuons colours need to know before
Cu2+
Fe2+
Fe3+
Mn2+
Blue
Pale green
Yellow
Pale pink
4 ions when added with NAOH ?
What happens when you add continuous NaOH?
Cu2+ —> Cu(OH)2 s BLUE
Fe2+ —> FE(OH)2 green
Fe 3+ —> Fe (OH)3 orange brown
Mn 2+ —> Mn(OH)2 Light browm
All are INSOLUBLE with excess NaOH
What happens when Fe 2 + reacts with NaOH but then reacts with air too?
Pale green —> GREEN—> BROWM at surface
This is because Iron (2) becomes oxidised to Iron (3) in air
Chromium 3+ ion solution colour + NAOH colour + EXCESS NaOH colour
Chromium 3+ = violet
With NaOH = Grey predicate (remember from before)
BUT THIS DISSOLVES IN EXCESS NaOH to form [ Cr(OH)6 ] 3-
All predication reaction summary
Cu2+ Blue = Copper hydroxide blue
Fe 2 +. (Pale green) = Green = Brown with air as Fe2+ oxidised ti Fe3+
Fe 3+ yellow = Orange brown
Mn2+ PALE PINK = Light brown
Cr3+ violet = grey = Green comolex ion cr (Oh)6
