NAME OF GROUP MEMBERS :
STUDENT ID :
NO OF EXPERIMENT :
TITLE OF EXPERIMENT : PREPARATION OF BIS(ACETYLACETONATO)COPPER(II) DATE OF EXPERIMENT :
PRACTICAL GROUP :
To synthesize the bis(acetylacetonato) copper(II)
To identify the nature of ligand.
Bis(acetylacetonato) copper(II) is a complex ion with copper ion in the centre surrounded by other molecules or ions weakly or more strongly bonded to it. The surrounded ions or molecules are called ligands. Ligands acts as Lewis base. It is attached to the centre metal ions by providing lone bond pairs to it. The active metal acts as Lewis acid, accepting electron lone pairs from ligands. The bonding which attach ligands and the centre metal ion together is coordinate bond or dative bonds. It is a type of covalent bond where the ligands shares its lone paired electrons with the centre metal cation. Coordination number is the number of ligand ions or molecule bonded to the cation. The centre metal ions which from complex ions are also known as cations. To form complex ions, cations musts have empty orbitals with low energy such as 3d and 4s orbitals to accept lone pair electrons from ligands. Cations with higer charge attracts ligands more easily. D-block metals with their high charge and empty orbitals have these features. So, it can form complex ions readily.
Apparatus and Materials:
Measuring cylinder, suction filter, measuring cylinder, beaker, conical flask, petri dish, glass rod, copper(II)nitrate, water, ammonia, acetyl acetone
6g of Copper(II) nitrate (Cu (NO3)2.3H2O) is dissolved in 60cm 3 of water. 2.
The solution of 1.1 ammonia was added slowly and with stirring until the precipitate first formed had redissolved. 3.
The solution was stirred continuing then 6cm 3 of acetyl acetone was added drop wise. 4.
The crude product was filtered off by using suction filtration. 5.
It was washed well with water, thoroughly drained it.
Percentage (%) yield was calculated.
Mass of Cu(NO3)2.3H2O
Mass of crude product + wash glass
Mass of wash glass
Mass of crude product
When ammonia dissolve in water,
NH3 + H2O NH4 + + OH-
Cu(NO3)2 + 2NH4OH Cu(OH)2 + 2NH4NO3 ----- (1)
Cu(OH)2 + 4NH3 -> Cu(NH3)42+ + 2OH- --------（2）
(Cu(NH3)4)2+ + 2CH3COCH2COCH3 -> Cu(CH3COCH2COCH3)2 -----（3） Molar mass of Cu( NO3)2.3H2O = 241g mol-1
No. of moles of Cu( NO3)2.3H2O = 6.0168
241 =0.025 mol From the equation(2) , we can conclude that:
1 mol of Cu2+ produces 1 mol of Cu(NH3)4 2+
From equation (3), 1 mol of Cu(NH3)4 2+ produce 1 mol of C10H16CuO4 Molar mass of product C10H16CuO4 = 263.78g
0.025mol of Cu(OH)2 produce 0.025 mol of Cu(NH3)4 2+
Theoretical yield = 0.025 x 263.78g
Percentage = Actual Yield x 100% = 1.4810 x 100% yield of product Theoretical Yield 6.5945 = 22.4581%
At the beginning, copper (II) nitrate is added into the water. The solution is light blue. Then when copper (II) solution is added with ammonia, pale blue solid precipitate of Copper Hydroxide, [Cu(OH)2] is formed. When excess ammonia is added into Copper Hydroxide, a complex is form between ammonia molecules...
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