E6
• Pre-lab report (p.159) due at the start of lab
 Single session two hour lab experiment.
 Teams analyze 3 assigned reactions.
Analysis of Reactions, E 6
- 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.
 Teams present one of the 3 reactions in discussion
during the first hour of the next session.
Analysis of a Non - Reaction
Record your qualitative observations of individual
reagents and the reagent mixture.
• Design and conduct a minimum of two
quantitative tests and experiments to confirm that
no reaction occurred.
• Do NOT conduct reference blank tests!
Analysis of A Non-Reaction
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and colorless
SnCl 4 (aq) + KI (aq) → Clear
________
Analysis of A Non-Reaction
Example 1
SnCl 4 (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°.
SnCl4 + KI → no reaction?
Q. Why does Test C (SnCl 2 + I 2 → colorless hexane
phase) support “no reaction”?
Test C
Hexane is colorless and therefore reaction occurred
net rxn: Sn 2+ + I 2 → Sn 4+ + 2 I -
B) KCl (aq) + KI (aq) + hexane→ clear, colorless phases
C) SnCl2 (aq) +I 2 (aq) + hexane → clear, colorless phases.
______________________________
Answer: ________________
Analysis of a non - reaction
Reaction?
Example 2:
Ag(s)
silver solid
+
Co(NO 3)2(aq) →
no visible change
clear red solution
DEMO
 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: Reaction 1
Reaction 1:
Add 20mL 0.10M SnCl 2 to 2.0mL of 0.10M Hg(NO3) 2
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Q. What tests could you conduct to confirm that “no
reaction” has occurred?
SnCl2 + Hg(NO 3)2 →white ppt. → gray-bl ppt.
Identify Reactant and Spectator Species.
Reaction:
Add 20mL 0.10M SnCl 2 to 2.0mL of 0.10M Hg(NO3) 2
Hypothesis: “Hg2+ is a reactant”.
Identify Reactant and Spectator Species.
Reaction 1:
Add 20 mL 0.10 M SnCl2 to 2.0 mL of 0.10M Hg(NO3)2
Identify Reactant and Spectator Species.
Reaction:
Add 20mL 0.10M SnCl 2 to 2.0mL of 0.10M Hg(NO3) 2
Hypothesis: “Hg2+ is a reactant”.
Test 1 DEMO
Test:
Test 1:
20mL 0.10M SnCl 2 to 2.0mL of 0.10M NaNO3 →
20mL 0.10M SnCl 2 to 2.0mL of 0.10M NaNO 3 → no reaction
Q. Is the test an appropriate test of the hypothesis?
Q. What do the test results tell you about the reaction?
_______
___________________
SnCl2 + Na(NO 3) →
_________
?
1. Identify Reactant and Spectator Species.
Reaction 1:
Add 20mL 0.10M SnCl 2 to 2.0mL of 0.10M Hg(NO3) 2
Test 2 DEMO
NaCl
+ Hg(NO 3)2 → __________?
Q. What do the test results tell you about the reaction?
__________________
Product Identification
2. 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.
• Write a net reaction.
Reaction:
SnCl2 + Hg(NO 3)2 →
Tests determine:
solid
“The reactants are Hg2+ and Sn2+”.
Q. Based on your knowledge and logic:
1. What type of reaction is occurring?
2. What is the likely identity of the solid product?
1._________ .
2. _______________
Product Identification
Analysis of Reactions: Reaction 2
Reaction 2:
0.10 M CuSO4 + HCl (con) → yellow-green solution
Reactants:
Sn2+ +
Hg2+
→
solid = ?
Q. Test that will directly determine if Cl - is a reactant?
Team tests:
(1) Add concentrated HNO 3 to 0.1 M CuSO 4.
(2) Add concentrated HCl to 0.1M Cu(NO 3)2.
(3) Add concentrated NaCl to 0.1 M CuSO4.
Possible oxidation state of reactants:
Sn
Sn2+
Sn4+
Hg
Hg2+
Q. What type of reaction is likely occurring?
Solid product?
= _______
Design/conduct tests to identify reactants and spectators .
Reaction:
0.10 M CuSO4 + HCl (con) → yellow-green solution
blue
colorless
___________________________.
DEMO
Q. If the hypothesis is correct, what will you observe
when conducting the test?
____________________________
DEMO
Reaction:
0.10 M CuSO4 + HCl (con) → yellow-green solution
blue
Identify the reaction type.
(after confirming reactant identities)
Identify Products and Write A Net Reaction.
colorless
Reactants confirmed:
Q. Test that will directly confirm if SO 42- is a spectator?
Team tests:
(1) Add concentrated HNO 3 to 0.1 M CuSO 4.
(2) Add concentrated HCl to 0.1M Cu(NO 3)2.
(3) Add concentrated NaCl to 0.1 M CuSO4.
Q. If the hypothesis is correct, what will you observe
when conducting the test?
______________________________________
Cu2+(aq) +
(blue)
Cl- (aq) → yellow-green solution
(colorless)
Type of reaction?:
__________________________
HCl(con) + CuSO4(aq) →
Colorless
blue
yellow-green
Q. Complete the net reaction:
_ Cl- + __ [Cu(H2O)4]2+ →
________________________________
Confirm the product identity.
[Cu(H 2O) 4]2+ + 4 Cl - →
[Cu(Cl)4]2- + 4H2O
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 the product identity.
[Cu(H 2O) 4]2+ + 4 Cl - →
Confirm the product identity.
[Cu(Cl)4]2- + 4H2O
Example
1. Add a better base such as ________
[Cu(H 2O) 4]2+ + 4 Cl - →
[Cu(Cl)4]2- + 4H2O
+
4 NH3
↓
[Cu(NH3)4]2+
+
4 H2O
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Note: Cu 2+ bonds with NH3
rather than Cl-.
Confirm the product identity.
[Cu(H 2O) 4]2+ + 4 Cl - →
[Cu(Cl)4]2- + 4H2O
Example
1. Add an acid such as ________
Questions?
Contact [email protected]
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