Ni & Cu Coordination ComplexesNi & Cu Coordination Complexes
• Hand in: Pre-Lab, OPEN EXCEL
• Today, we will study the reactions of different coordination complexes with ethylenediamine to determine if minor differences in structure make a difference in chemical reaction
OH2
NiOH2
H2O
H2O
OH2
OH2
CuOH2
OH2H2O
H2O
OH2
OH2
2+2+
Ni(H2O)6+2 Cu(H2O)6
+2
+ H2NCH2CH2NH2
OH2
NiOH2
NH2O
H2O
N
OH2
NiH2O
H2O OH2
OH2
OH2
.. ..+ 2H2O
2+ 2+
N N = H2NCH2CH2NH2
N
NiN
NN
N
N
Ni & Cu Coordination ComplexesNi & Cu Coordination Complexes Let’s consider the reaction between
¨ ¨
Ni(H2O)6
+2 + H
2N CH
2CH
2NH
2
Ni(H2O)6+2 + ethylenediamine (en) – first step
Ni(en)3 +2
coordination complex after three additions of en
What will happen with Copper Complex’s slightly different geometry??
Ni & Cu Coordination ComplexesNi & Cu Coordination Complexes
For the Experiment:
1. Set up Data Collection and Graph in EXCEL,
a. on the x axis: Time (in secs) collect data every 10 secs
b. on the y axis: Temp (oC) – note temperature change, when temperature
is stable and not decreasing, add next volume of (en)
c. Graph Live so you know when to add the next (en)
2. Prepare Equipment
a. Coffee Cup Calorimeter
b. Thermometer from Drawer
3. Obtain Reagents – WRITE DOWN CONC. ON BOTTLES
ALL VOLUMES MUST BE EXACT!!!!
a. Trial 1 - Nickel Complex – GREEN
b. Ethylenediamine (en) – IN FUME HOOD
WEAR GLOVES
DISPENSE INTO A TEST TUBE AND COVER WITH PAPER
ADD EN UNTIL NO CHANGE IS NOTED IN TEMP. (No more than 4 steps
for either Trial)
c. Trial 2 – Copper Complex – BLUE
Ni & Cu Coordination ComplexesNi & Cu Coordination Complexes
4. Actual Experimenta. obtain baseline temperature data for at least one to two
minutesb. add (en)c. immediately cover and gently swirld. collect data until temperature plateause. try not to let temperature dropf. add next (en) to the solution and repeat until temp no
longerrises (no more than 4 (en) additions per trial).
5. SAVE YOUR DATA, RENAME!!!, and go to trial 2 with Cu +2
complex
6. ALL WASTE IN LARGE CONTAINER IN FUME HOOD
qJ
g Cx
g
mLx mL of each step x T Trxn o f i
3 8 1 1. .
( ) enmol
qH rxn
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 75019.4
19.8
20.2
20.6
21.0
21.4
21.8
22.2
22.6
23.0
23.4
23.8
24.2
24.6
25.0
25.4
25.8
Thermo-Profile of the Nickel Coordination Complex
Time (seconds)
Tem
per
atu
re (
oC
)
Ni & Cu Coordination Complexes – Graphing in EXCEL (page 4 step 3)
Ni & Cu Coordination Complexes – Graphing in EXCEL (page 4 step 3)
Reaction of Ni
Ti Tf
DT V(soln) m(soln) S qrxn (J) mol en DH (kJ/mol)
Step 1 3.8 0.00750
Step 2 3.8
Step 3 3.8
Average
Reaction of Cu
Ti Tf
DT V(soln) m(soln) S qrxn (J) mol en DH (kJ/mol)
Step 1 3.8
Step 2 3.8
Step 3 3.8
Average
Ni & Cu Coordination Complexes – Calculations in EXCEL (Table on Page 5)
Ni & Cu Coordination Complexes – Calculations in EXCEL (Table on Page 5)
Data Table to be generated in EXCEL by students:
Ni & Cu Coordination ComplexesWhat to do with the data?
Ni & Cu Coordination ComplexesWhat to do with the data?
enmol
qH rxn
Where: q rxn = energy released by the reaction
mass sol. = TOTAL mass of liquid in the calorimeterTf = Final Temperature in the STEPTi = Initial Temp in the STEP
So: mass sol. = density of liquid (g/mL) x mL of TOTAL soln.
Then:
Where:ΔH = Heat of reaction (kJoules/mole)mol (en) = moles of en in the STEP
q rxn = - (3.8 J/g oC ) x masssol. x (Tf – Ti)
WATCH YOUR UNITS = Joules or Kilojoules!!!!
Lab ReportLab Report Title Page Purpose Results
- Two Graphs (page 5, #1)
Ni(H20)6+2 and ethylenediamine
Cu(H20)6+2 and ethylenediamine
- EXCEL Table, page 5, #2, (with sample calculations for Ni and Cu)
- Present/Staple in order data/calculations were obtained/performed
- Significant Figures and Units
- Precision and Accuracy
Conclusion Avg ΔH for Ni reaction and Avg ΔH for Cu reaction Number of en’s per Ni complex (question #3, page 5) Number of en’s per Cu complex (question #3, page 5) Errors and Improvements
Individual Checked-Pre-labs
