Notes Ions in Solution for secondary chemistry

Walks chemistry students through ionic reaction equations

1. Chapter 13
Ions in Aqueous
Solutions

2. The dissolving process–
The ions are hydrated by water molecules

3. Dissociation-
Ionic Substances
•Dissociation – the separation of ions when
dissolved
 
(ionic- salts and bases)
 

•Ex: 
LiCl    
 
    Li
+
(aq) 
  
+
     Cl
-
  
(aq)
 

1 mole
        1 mole        1 mole       
 
H
2O

4. Double Replacement and Precipitation Reactions
Soluble = dissolved (aq)
Not soluble = will not dissolve (s)
•See Solubility Chart
•Involves a chemical reaction for substances that dissociate or ionize producing a double replacement reaction.
(NH
4)
2S (aq) + Co(NO
3)
2
(aq)  2 NH
4NO
3 (aq) + CoS
(s)

5. Double Replacement Reactions Double Replacement Reactions
Steps:Steps:
 1) 
 
Write a balanced chemical equation
2) Look up solubility of both products formed – put in symbols
3) Write an ionic equation- Write an equation with each material in
a dissociated form. Include charges.
4) Write a net ionic equation  - only the materials that form a
solid.  Leave the spectator ions out.
5) Label Spectator ions – ions not involved in forming the ppt. 
6) Identify the Precipitate - if a solid is formed
 

6. Double Replacement Reactions Double Replacement Reactions
Steps:Steps:
 1) 
 
Write a balanced chemical equation
(NH
4
)
2
S (aq) + Zn(NO
3
)
2
(aq)  2 NH
4
NO
3
+ ZnS
2) Look up solubility of both products formed – put in symbols

(NH
4)
2S (aq) + Zn(NO
3)
2
(aq)  2 NH
4NO
3
(aq)
+ ZnS
(s)

7. Double Replacement Reactions Double Replacement Reactions
Steps:Steps:
3) Write an ionic equation- Write an equation with each material in a
dissociated form. Include charges.
2 (NH
4
)
+1
(aq)
+ S
-2
(aq)
+ Zn
+2
(aq)
+ 2NO
3
-1
(aq)
 2NH
4
+1
(aq)
+2NO
3
-1

(aq)
+ ZnS
(s)
 

8. Double Replacement Reactions Double Replacement Reactions
Steps:Steps:
4) Write a net ionic equation  - only the materials that form a solid. 
Leave the spectator ions out.
 
S
-2
(aq) + Zn
+2
(aq)  ZnS
(s)

9. Double Replacement Reactions Double Replacement Reactions
Steps:Steps:
5) Label Spectator ions – ions not involved in forming the ppt. 
NH
4
+1
+ NO
3
-1

6) Identify the Precipitate - if a solid is formed
ZnS
(s)
Zinc Sulfide
 

10. EX 1: Aqueous solutions: ammonium sulfide and copper (II) nitrate
Formula equation
(NH
4
)
2
S (aq) + Cu(NO
3
)
2
(aq)  2 NH
4
NO
3
(aq) + CuS (s)
Overall Ionic equation:
2NH
4
+
(aq)

+ S
2-
(aq) + Cu
2+
(aq) + 2NO
3
1-
(aq)  2 NH
4
+
+ 2 NO
3
1-
+ CuS (s)
Net Ionic equation: Cu
2+
(aq) + S
2-
(aq)  CuS (s) Spectator Ions: NH
4
+
+ NO
3
1-

precipitate = copper (II) sulfide
EX 2: Aqueous solutions: calcium chloride and potassium phosphate
Formula equation:
3CaCl
2 (aq) + 2 K
3PO
4 (aq)  Ca
3(PO
4)
2 (s) + 6 KCl (aq)
Overall Ionic equation:
3Ca
2+
(aq) + 6Cl
-
(aq) + 6K
+
(aq) + 2PO
4
3-
(aq)  Ca
3
(PO
4
)
2
(s) + 6K
+
(aq) + 6 Cl
-
(aq)
Net Ionic equation: Spectator Ions:
3 Ca
2+
(aq)

+

2

PO
4
3-
(aq)

 Ca
3(PO
4)
2 (s) K
+
+ Cl
-
precipitate = calcium phosphate
EX 3: Aqueous solutions: aluminum nitrate and potassium carbonate
Formula equation: 2 Al(ClO
3
)
3
(aq) + 3 Na
2
CO
3
(aq)  Al
2
(CO
3
)
3
(s) + 6 NaClO
3
(aq)
Overall Ionic equation:
2Al
3+
(aq) + 6ClO
3
-
(aq) + 6Na
+
(aq) + 3CO
3
2-
(aq)  Al
2(CO
3)
3 (s) + 6 Na
+
+ 6ClO
3
-
(aq)
Net Ionic equation Spectator Ions:
2Al
3+

(aq)
+ 3CO
3
2-

(aq)
 Al
2
(CO
3
)
3

(s)
Na
+
+ ClO
3
–

precipitate = aluminum carbonate