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- Gravimetric method used to:
- analyzed complex compound for nickel
- Spectrophotometry used to:
- confirm the stoichiometry of the complex
- Nickel and ammonia form a
- coordination compound
- Ammines
- metal-ammonia complexes
- Alfred Werner
- laid foundation of coordination chemistry by series of ammine complexes of cobalt
-
Hexaammine complex=......
Reaction= -
formed by nickel and ammonia.......
: Ni2+ + 6NH3 --> [Ni(NH3)6]2+ -
Coordinate bond=....
coordinate bond between.... what? in exp 5 - covalent bond in which one atom donates both electrons of the shared pair................5= coord bond between nitrogen atom of the ammonia molecule and the nickel II ion...
- Coordination number of metal=
- number of donor atoms surrounding the metal ion.....
- In hexammine nickel II complex.... donor atom= ? and coordination number =?
-
donor atom= ammonia......#= 6
- Analysis of the nickel II ammine complex for ammonia....:::: ...TITRATION=_______. END PT of TITRATION= ________. WHAT INDICATOR USED: ______. COLOR CHANGES EXPECTED ARE FROM ____ to _____.
- Titration= excess HCl and standardized NaOH... end pt want to titrate all of Hcl not ammonium ions...../// Indicator used= Bromescol Green b/c lower pH.../// color change expected = RED TO GREEN... but actually ORGANGE TO GREEN BLUE.... because nickel II = green..
- Indicator used in analysis of nickel II ammine complex=
- Mix of bromescol green and methyl red because lower pH... RED TO GREEN
- Determination of Nickel II in nickel ammine complex using what process and what ligand??
- Process= Gravimetric analysis &&& ligand = Dimethylglyoxime
- Gravimetric analysis=
- analytical method based upon isolalting desired molecule from compoud usually by precipitation
- Silver Nitrate=
- common inorganic reagent used to precipitate halide ions
- Barium chloride=
- inorganic reagent to preciptate sulfate ion
- Organic precipitating reagents:
- have functional groups like carboxyl to make anions that combine with inorganic metal ions to form insoluble salts
- Organic preciptiating agents contain N or O donor atoms that can:
- coordinate to the metal ion to form insoluble complex xompounds
- Chelating reagents=
- organic preciptating agents that contain N or O donot atoms that can coordinate to metal ion to form insoluble complex compounds........EX= chleating agent EDTA
- Nickel II forms a stable coord compound with organic reagent=
- Dimethylglyoxime
- Adding DMG to solution of Ni 2 =
- precipitation of red Ni(DMG)2 complex
- How do you determine the original amount of nickel in solution?
- Add DMG to solution of Ni 2+... and immediately preciptates into red Ni complex.. Ni(DMG)2 -.. then isolate and determine mass
- DMG is a _1___. Has _2_ donor atoms that ____3_ with the same ____4____ to form a __5__.
-
1. Chelating Ligand.
2. has 2 donor atoms that
3) coordinate with the same
4) Nitrogen ion to form a
5) chelating ring - How is complex Ni (DMG)2 stabilized?
- 2 more 6 membered rings are formed thru H bonding between the 2 chelating ligands
- How does the neutral NiDMG readily preciptate??
- Loss of H ions from 2 DMG molecules upon complex formation.
- Blue litmus paper=
- If slighlt acidic... should turn fmor blue to red
- when trying to precip Ni from solution (NIDMG COMPLEX).. filtrate turns red during filtrattion.. means?
- precipitation not complete..
- Gravimetric factor
- ratio of nickel ammine complex and nickel DMG complex
- Spectrophotometry:
- Dtermine stoicimoetry of Ni2 ammine complex.....By change in color as ni 2 and ammonia soltions are mixed.. possible to determine the ratio of ammmonia to nickel II in complex
- Determine amt of ammonia in Ni2 complex by:
-
neutralize ammonia by adding excess Hcl.........../// THEN
.... titrate excess HCl against NaOh - Amt of nickel in complex determined by:
- gravimetric analyssis using DMG as precipatting reagent
- Spectrophotometer used to establish spectrum of both:
- nickel II nitrate && nickel II amine
- Determine electrical acharge by an electron
- by meaasureing quantiity of copper deoposited from a solution qith Cu ions by a measured quanitiy of electricity
-
Change on an electron:
Measure _____ and _____... and DEtermine:: ____ -
Measure: quantitiy of copper dipsotied and electrical charge (current x time)
determine:: amt of electrical chagre carried by one electron - Electrochemical Cell
- energy absorbed/ given off in reaction in form of electricty... 2 types= voltaic/ galvanic and Electrolytic
- 2 kinds of electrochemical cells=
- Voltaic/galvanic OR electrolytic
- Both types of electrochem cells have 2 ____.
- Electrodes- where ocidation and reduction take place...
-
Voltaic cell-
Electrolytic- -
chem reaction makes electrical energy////
electrical energy-- cause chem reaction - Electrolytic cell
- Electricity used to make chemical reaction... by electrodes in molten saly/ solution with salt/ srong electrolyte
- Electrolytic cell reaction
- electrical energy from 6 V battery moves Cu metal from anode to cathode..
- Hexaaqua complx
- metal salt dissolbed in water.. water molecules coordinate to metal ion
- CHelating ligand
- ligand has more than one donor atom from which donation of elevctrons to metal is possible.....
- Oxalate ion
- Chelating ligand... Bidentatee so 2 donoor atoms to coordinate bond.... so each oxaltae ion can from one chelate ring with ironiII
- Potassium permanganete solution
- needed to analyse iron oxalate complex
- COlor of precipitate of hydrated iron II oxalate
- YELLOW
- COlor of precip iron III OH
- BROWN from peroxide.. and potassium oxalate and iron oxalate
-
Iron oxalate complex (precipitate) describe=
before when afdding oxalic acid turn: -
green cryystals
...
greeener.. - find amt of oxalate inpotasium trioxalate erate complex:
- by using potass permang as oxidizing agent.. useding redox titration..
- KMnO4 + oxalate ion
- Redox rection... permangante ion reduced/ oxaltate oxidized
- Molar ratio of oxalate to permangahete = 5/2...
- unknown oxalate.. known permangate.. vol titration
- Standardized
-
solution must be standardized so concentration of it in solution is accurately known...... USED with KMnO4 and NaOH
--concentration of solution is measured by alloweing it to react with a pure substance - Standard solution
- concentration accurrately known
- Primary standard
-
pure substance used to standardize a solution
....
KHP... known quantitiy that standardizes NaOH solution by acidbase tit.///////
sodium oxalate.. standardizes KMnO4 - Iron oxalate complex titrated with standardized KMnO4..
- yellow --> pink.. no brown because rust Mn o2
- Stereoisomerism
-
dif arrangements of same set of donor atoms in metal ion
... Optical/ gemometriclal - Stricutral isomerism
-
dif set of donor atoms ...
Linkage- ligand with more than one possible wat of coorinating to the metal ion becuase more the one possible donor atom... - Nitrite ion....
-
AMBIDENTATE--- monodetate.. n or O... and thru more than one
..or bidentate... chelating to a single metal ion or briding two metal ion