Transcript Document

Applied
Le Chatelieir's
Principle
Lesson 4
Lab 19A
Le Chatelier’s Principle
Copy the five Equilibrium Equations into your lab handout
Part I
Thymol Blue (blue)
+
H+ ⇌
Thymol Blue (yellow)
Part II
Fe3+(aq)
+ SCN-(aq) ⇌
yellow
Fe3+(aq)
FeSCN2+(aq)
brown
+
3OH- →
Fe(OH)3(s)
Part III
Co(H2O)62+ + 2Cl- ⇌ Co(H2O)4Cl22- +
pink
blue
2H2O(l)
Part IV
Energy
+ 2CrO42- + 2H+
yellow
Ba2+
+
CrO42-
⇌
Cr2O72- +
orange
→
H2O(l)
BaCrO4(s)
Part V
Cu(H2O)42+ + 2NH3 ⇌
light blue
Cu(OH)2(s) +
powder blue
Cu(OH)2(s) + 4NH3 ⇌
powder blue
Cu(NH3)42+ + 2OHviolet
2NH4+
+ 2H2O
Application of Le Chatelier’s Principle
2CrO42- + 2H+
yellow
Know the following:
Energy
+
⇄
Cr2O72- +
orange
H2O(l)
Any acid is H+
Any base is OH-
Acids react with bases H+ + OH- → H2O(l)
Stress
Add H+
Add CrO42Add Cr2O72-
Shift
[CrO42-]
[Cr2O72-]
colour 
Application of Le Chatelier’s Principle
2CrO42- + 2H+
yellow
Know the following:
Energy
+
⇄
Cr2O72- +
orange
H2O(l)
Any acid is H+
Any base is OH-
Acids react with bases H+ + OH- → H2O(l)
Stress
Add H+
Add CrO42Add Cr2O72-
Shift
[CrO42-]
[Cr2O72-]
colour 
Application of Le Chatelier’s Principle
2CrO42- + 2H+
yellow
Know the following:
Energy
+
⇄
Cr2O72- +
orange
H2O(l)
Any acid is H+
Any base is OH-
Acids react with bases H+ + OH- → H2O(l)
Stress
Add H+
Add CrO42Add Cr2O72-
Shift
[CrO42-]
[Cr2O72-]
colour 
Application of Le Chatelier’s Principle
2CrO42- + 2H+
yellow
Know the following:
Energy
+
⇄
Cr2O72- +
orange
H2O(l)
Any acid is H+
Any base is OH-
Acids react with bases H+ + OH- → H2O(l)
Stress
Shift
[CrO42-]
[Cr2O72-]
colour 
Add H+
right
decrease
increase
orange
Add CrO42Add Cr2O72-
Application of Le Chatelier’s Principle
2CrO42- + 2H+
yellow
Know the following:
Energy
+
⇄
Cr2O72- +
orange
H2O(l)
Any acid is H+
Any base is OH-
Acids react with bases H+ + OH- → H2O(l)
Stress
Shift
[CrO42-]
[Cr2O72-]
colour 
Add H+
right
decrease
increase
orange
Add CrO42-
right
increase
increase
?
Add Cr2O72-
Application of Le Chatelier’s Principle-1
2CrO42- + 2H+
yellow
Know the following:
Energy
+
⇄
Cr2O72- +
orange
H2O(l)
Any acid is H+
Any base is OH-
Acids react with bases H+ + OH- → H2O(l)
Stress
Shift
[CrO42-]
[Cr2O72-]
colour 
Add H+
right
decrease
increase
orange
Add CrO42-
right
increase
increase
?
increases
increases
?
Add Cr2O72- left
Application of Le Chatelier’s Principle-1
Energy
+
2CrO42- + 2H+
yellow
⇄
Cr2O72- +
orange
H2O(l)
Acids react with bases H+ + OH- → H2O(l)
Stress
Shift
[CrO42-]
[Cr2O72-]
colour 
Application of Le Chatelier’s Principle-1
Energy
+
2CrO42- + 2H+
yellow
⇄
Cr2O72- +
orange
H2O(l)
Acids react with bases H+ + OH- → H2O(l)
Stress
Add NaOH
Shift
[CrO42-]
[Cr2O72-]
colour 
Application of Le Chatelier’s Principle-1
Energy
+
2CrO42- + 2H+
yellow
⇄
Cr2O72- +
orange
H2O(l)
Acids react with bases H+ + OH- → H2O(l)
NaOH
→
Stress
Shift
Add NaOH
Na+
+
[CrO42-]
OH-
[Cr2O72-]
colour 
Application of Le Chatelier’s Principle-1
Energy
+
2CrO42- + 2H+
yellow
⇄
Cr2O72- +
orange
H2O(l)
Acids react with bases H+ + OH- → H2O(l)
NaOH
→
Stress
Shift
Add NaOH
Na+
+
spectator ion
[CrO42-]
OHstress ion- lowers H+
[Cr2O72-]
colour 
Application of Le Chatelier’s Principle-1
Energy
+
2CrO42- + 2H+
yellow
⇄
Cr2O72- +
orange
H2O(l)
Acids react with bases H+ + OH- → H2O(l)
NaOH
→
Stress
Shift
[CrO42-]
[Cr2O72-]
colour 
Add NaOH
left
increases
decreases
yellow
Na+
+
spectator ion
OHstress ion- lowers H+
Application of Le Chatelier’s Principle-1
Energy
+
2CrO42- + 2H+
yellow
⇄
Cr2O72- +
orange
H2O(l)
BaCrO4 has low solubility
BaCr2O7 has high solubility
Stress
Shift
[CrO42-]
[Cr2O72-]
colour 
Application of Le Chatelier’s Principle-1
Energy
+
2CrO42- + 2H+
yellow
⇄
Cr2O72- +
orange
H2O(l)
BaCrO4 has low solubility
BaCr2O7 has high solubility
Stress
Ba(NO3)2
Shift
[CrO42-]
[Cr2O72-]
colour 
Application of Le Chatelier’s Principle-1
Energy
+
2CrO42- + 2H+
yellow
⇄
Cr2O72- +
orange
H2O(l)
BaCrO4 has low solubility- Ba2+ reacts with CrO42BaCr2O7 has high solubility- no reaction
Ba(NO3)2
→
Stress
Shift
Ba(NO3)2
Ba2+
+
[CrO42-]
2NO3[Cr2O72-]
colour 
Application of Le Chatelier’s Principle-1
Energy
+
⇄
Cr2O72- +
orange
+
2NO3spectator
[CrO42-]
[Cr2O72-]
2CrO42- + 2H+
yellow
H2O(l)
BaCrO4 has low solubility
BaCr2O7 has high solubility
Ba(NO3)2
→
Stress
Shift
Ba(NO3)2
Ba2+
stress
colour 
Application of Le Chatelier’s Principle-1
2CrO42- + 2H+
⇄
Cr2O72- +
yellow
orange
↓ Ba2+ reacts with this ion
BaCrO4 has low solubility
BaCr2O7 has high solubility
Energy
+
Ba(NO3)2
→
Stress
Shift
Ba(NO3)2
Ba2+
stress
+
2NO3spectator
[CrO42-]
[Cr2O72-]
H2O(l)
colour 
Application of Le Chatelier’s Principle-1
2CrO42- + 2H+
⇄
Cr2O72- +
yellow
orange
↓ Ba2+ reacts with this ion
BaCrO4 has low solubility
BaCr2O7 has high solubility
Energy
+
Ba(NO3)2
→
Stress
Ba(NO3)2
Ba2+
stress
H2O(l)
+
2NO3spectator
Shift
[CrO42-]
[Cr2O72-]
colour 
left
decreases
decreases
yellow
Application of Le Chatelier’s Principle-1
Energy
Stress
HCl
+
2CrO42- + 2H+
yellow
Shift
⇄
[CrO42-]
Cr2O72- +
orange
[Cr2O72-]
H2O(l)
colour 
Application of Le Chatelier’s Principle-1
2CrO42- + 2H+
yellow
⇄
Cr2O72- +
orange
HCl
→
+
Cl-
Stress
Shift
Energy
HCl
+
H+
[CrO42-]
[Cr2O72-]
H2O(l)
colour 
Application of Le Chatelier’s Principle-1
2CrO42- + 2H+
yellow
⇄
Cr2O72- +
orange
HCl
→
+
Clspectator
Stress
Shift
[CrO42-]
[Cr2O72-]
Energy
HCl
+
H+
stress
H2O(l)
colour 
Application of Le Chatelier’s Principle-1
2CrO42- + 2H+
yellow
⇄
Cr2O72- +
orange
HCl
→
+
Clspectator
Stress
Shift
[CrO42-]
[Cr2O72-]
colour 
HCl
right
decreases
increases
orange
Energy
+
H+
stress
H2O(l)
Application of Le Chatelier’s Principle- 2
Energy + Co(H2O)62+ + 2Clpink
Stress
HCl
stress ion
⇄
spectator ion
Co(H2O)4Cl22- +
blue
shift
2H2O(l)
colour 
Application of Le Chatelier’s Principle- 2
Energy + Co(H2O)62+ + 2Clpink
HCl
→
Stress
stress ion
HCl
H+
⇄
Co(H2O)4Cl22- +
blue
+
Cl-
spectator ion
shift
2H2O(l)
colour 
Application of Le Chatelier’s Principle- 2
Energy + Co(H2O)62+ + 2Clpink
HCl
→
Stress
stress ion
HCl
H+
spectator
⇄
Co(H2O)4Cl22- +
blue
+
Clstress
spectator ion
shift
2H2O(l)
colour 
Application of Le Chatelier’s Principle- 2
Co(H2O)62+ + 2Clpink
HCl
→
Stress
stress ion
HCl
Cl-
⇄
H+
spectator
Co(H2O)4Cl2 + 2H2O(l)
blue
+
spectator ion
H+
Clstress
shift
right
colour 
blue
Application of Le Chatelier’s Principle- 2
Energy + Co(H2O)62+ + 2Clpink
Stress
stress ion
Increase temperature
⇄
spectator ion
Co(H2O)4Cl22- +
blue
shift
2H2O(l)
colour 
Application of Le Chatelier’s Principle- 2
Energy + Co(H2O)62+ + 2Clpink
Stress
stress ion
Increase temperature
⇄
spectator ion
Co(H2O)4Cl22- +
blue
shift
2H2O(l)
colour 
Application of Le Chatelier’s Principle- 2
Energy + Co(H2O)62+ + 2Clpink
⇄
Co(H2O)4Cl22- +
blue
Stress
stress ion
spectator ion
shift
↑ temp
none
none
right
2H2O(l)
colour 
blue
Application of Le Chatelier’s Principle- 2
Energy + Co(H2O)62+ + 2Clpink
Stress
AgNO3
stress ion
⇄
spectator ion
Co(H2O)4Cl22- +
blue
shift
2H2O(l)
colour 
Application of Le Chatelier’s Principle- 2
Energy + Co(H2O)62+ + 2Clpink
AgNO3
→
Stress
stress ion
AgNO3
Ag+
+
⇄
Co(H2O)4Cl22- +
blue
2H2O(l)
NO3-
spectator ion
shift
colour 
Application of Le Chatelier’s Principle- 2
Energy + Co(H2O)62+ + 2Clpink
AgNO3
→
Stress
stress ion
AgNO3
⇄
Co(H2O)4Cl22- +
blue
2H2O(l)
Ag+
+
NO3↑
stress- low solubility (data book-4) with Clspectator ion
shift
colour 
Application of Le Chatelier’s Principle- 2
Energy + Co(H2O)62+ + 2Clpink
⇄
Co(H2O)4Cl22- +
blue
2H2O(l)
AgNO3
→
Stress
stress ion
spectator ion
shift
colour 
AgNO3
Ag+
NO3-
left
pink
Ag+
+
NO3↑
stress- low solubility (data book-4) with Cl-
Here is a the first question from your lab. I will give you a good answer
so that you understand the level of detail that is required in the response
1.
Explain the colour changes observed when Fe(NO3)3, KSCN, and
NaOH were added to the thiocyanatoiron equilibrium system.
Start by writing the equilibrium equation.
Fe3+(aq) + SCN-(aq)
yellow
⇄
Fe(SCN)2+(aq)
brown
Adding Fe(NO3)3 increases the [Fe3+] and causes the reaction to shift
right and turn brown.
Adding KSCN increases the [SCN-] and causes the reaction to shift
right and turn brown.
Adding NaOH increases the [OH-] which reacts with Fe3+, lowering the
[Fe3+] causing the equilibrium to shift left and turn yellow.