E 6 Lab
• Pre-lab report (p.170) due at the start of lab
 Single session two hour lab experiment.
Analysis of Reactions, E 6
 Teams analyze 3 assigned reactions.
- one reaction may or may not be a non-reaction.
 Team report is due at the end of lab.
- report = write up of the analysis of the 3 reactions.
E 6 Discussion
 Teams present one of the 3 assigned reactions
during the first hour of the next session.
• Present what you did in lab and wrote up for your lab
report, regardless of whether it is right or wrong.
• Present what you actually did in LAB, and the logic you
used to justify your conclusions.
• If what you did in lab was wrong, explain where you went
wrong and why.
• Present things you could have done better, if any, to
analyze the reaction.
Analysis of a Non - Reaction
Analysis of a non - reaction
Analysis of a non - reaction
Example:
Ag(s)
+
silver solid
Record your qualitative observations of individual
reagents and the reagent mixture.
• Conduct a minimum of two quantitative tests and
experiments to confirm that no reaction occurred.
• Tests should demonstrate that no change in
reactant properties has occurred.
• Do NOT conduct reference blank tests!
Ag(s)
+
silver solid
Co(NO3 )2(aq) → no visible change
clear red solution
Co(NO3) 2(aq) → no visible change
clear red solution
Q. What tests or measurements could you conduct
to confirm that “no reaction” has occurred?
Ag(s) + Co(NO3)2(aq) → ?
Some example of tests or measurements:
1.
Analysis of A Non-Reaction
Reaction 2
SnCl4 (aq) + KI (aq) → ?
DEMO
Reaction 2
SnCl4 (aq) + KI (aq) → colorless
colorless
Q. Circle any test that can support “no reaction”:
A) The temperature of the original solutions and
reaction mixture shows no ∆ t°.
B) KCl (aq) + KI (aq) + hexane → clear, colorless phases
C) SnCl2 (aq) + I2(aq) + hexane → clear, colorless phases.
SnCl4 (aq) + KI (aq) →
clear and colorless solutions
Clear
and colorless
__________________
Answer: _________________
Analysis of A Non-Reaction
SnCl4 + KI
→
no reaction?
Q. Why does Test __ support “no reaction”?
Reaction?
 Record your qualitative observations of
individual reagents and the reagent mixture.
1) Determine the identity of reactants/spectators.
• Record hypothesis, tests, observations, and
conclusions.
_________________________________
Analysis of Reactions
Analysis of Reactions
Identify Reactant and Spectator Species
Reaction:
Add 20mL 0.10M SnCl2 to 2.0mL of 0.10M Hg(NO3) 2
Reaction:
Add 20mL 0.10M SnCl2 to 2.0mL of 0.10M Hg(NO3) 2
1.Record Observations:
Hypothesis: “Hg2+ is a reactant”.
Test :
20mL 0.10M SnCl2 to 2.0mL of 0.10M NaNO3 → ?
Add 20mL 0.10M SnCl2 to 2.0mL of 0.10M Hg(NO3)2
→ ______________?
SnCl2 + Hg(NO3) 2→ white ppt. → gray-bl ppt.
Colorless solutions
Q. Is the above test an appropriate test of the
hypothesis?
_____________
Identify Reactant and Spectator Species
Reaction:
SnCl2 + Hg(NO3) 2
colorless
white solid
gray-bl solid
Identify Reactant and Spectator Species
Reaction:
SnCl2 + Hg(NO3) 2
colorless
white solid
gray-bl solid
DEMO
Test:
SnCl2 + Na(NO3) → _________?
_______
Q. What do the test results tell you?
___________________
Identify Reactant and Spectator Species
Reaction:
Add 20mL 0.10 M SnCl2 to 2.0 mL of 0.10 M Hg(NO3) 2
white solid
gray-bl solid
DEMO
Test 2:
NaCl + Hg(NO3) 2 → _________?
___________
Q. What do test 2 results tell you?
_____________________
Test 3:
Sn(NO3)2 + Hg(NO3) 2 → _________?
gray-bl solid
Q. What do test 3 results tell you?
__________________________
Reaction Products?
• Compare product properties to
known samples.
• Consult reference texts and
compare listed properties to
observed product properties
• Conduct tests to help confirm
product ID.
• Indicate type of reaction occurring
• Write a net reaction.
Products and Reaction?
Reaction:
SnCl2 + Hg(NO3) 2 → white solid → gr-black solid
Test results:
Reactants = _______________________
_______________________
Product Identification
Reactants:
___________________________
Possible oxidation state of reactants:
1. What type of reaction is occurring?
2. What is the likely identity of the solid product?
1. _________
2. ____________________
Gr-black solid product?
= ____
Products and Reaction
Products and Reaction
Analysis of Reactions
Reaction:
Net redox reaction (gr-bl solid product):
______________________________
Add 20mL 0.10M SnCl2 to 2.0mL of 0.10M Hg(NO3)2
White intermediate insoluble product?
________________________
Check properties listed in CRC Handbook :
_______________________
SnCl2 + Hg(NO3) 2→ white ppt. → gray-bl ppt.
______
_____
Reaction 2:
0.10 M CuSO4 + HCl (con) → ?
Analysis of Reactions
Identify Reactants and Spectators
Reaction 2:
0.10 M CuSO4 + HCl (con) → _____________?
Analysis of Reactions
Reaction:
0.10 M CuSO4 + HCl (con) → yellow-green
blue
colorless
Q. Test that will directly determine if Cl- is a reactant?
(1)Add concentrated HNO3 to 0.1 M CuSO4.
(2)Add concentrated HCl to 0.1M Cu(NO3)2.
(3) Add concentrated NaCl to 0.1 M CuSO4.
Q. What type of reaction is likely occurring?
______________________
DEMO
Q. If the hypothesis is correct, what will you observe
when conducting the test?
______________________________
DEMO
Reaction 2:
0.10 M CuSO4 + HCl (con) → ?
Reaction:
0.10 M CuSO4 + HCl (con) → yellow-green soln
blue
colorless
Q.Test that will directly confirm if SO42- is a spectator?
(1)Add concentrated HNO3 to 0.1 M CuSO4.
(2)Add concentrated HCl to 0.1M Cu(NO3)2.
(3) Add concentrated NaCl to 0.1 M CuSO4.
Q. If the hypothesis is correct, what will you observe
when conducting the test?
_____________________________________
DEMO
Identify Reactants and Type of Reaction
Reactants:
Cu2+(aq) +
(blue)
Cl- (aq) →
yellow-green soln
(colorless)
Type of reaction?:
______________________
Identify Product/s and Write A Net Rxn
Product
_____________________
- Check the list of “common complex ions” or
the CRC Handook for the formula
Q. Complete the net reaction:
_ Cl- + __ [Cu(H2 O)4]2+ →
Confirm Reaction
[Cu(H2O)4]2+ + 4 Cl - →
________________
Q. How might you further confirm the identity of
the product and/or show that the product is formed
from a Lewis acid-base equilibrium reaction)?
Confirm Reaction
[Cu(H2O)4]2+ + 4 Cl - →
Confirm Reaction
[Cu(Cl)4]2- + 4H2O
[Cu(H2O)4]2+ + 4 Cl - →
_______________
Example 2
1. Add an acid such as ________
Example 1
1. Add a better base such as ________
DEMO
DEMO