1 ions in aqueous solutions and colligative properties chapter 13 modern chemistry sections 1 &...
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Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
1
Ions in Aqueous Solutions and Colligative Properties
Chapter 13 Modern Chemistry
Sections 1 & 2Compounds in Aqueous SolutionsColligative Properties of a Solution
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
2
Compounds in Aqueous Solutions
Section 13.1
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
3
VOCABULARYDissociation Equation PrecipitateNet Ionic EquationSpectator IonIonizationHydronium IonStrong ElectrolyteWeak Electrolyte
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
4
Conce
pt
Map
13
.1
NET IONIC EQUATIONS
DISSOCIATION
EQUATION
PRECIPITATE
REACTIONS
SPECTATOR
IONS
IONIZATION
HYDRONIUM ION
STRONG ELECTROLYTE
WEAK ELECTROLYTE
DISSOCIATION
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
5
Dissociation Equations• Dissociation is the separation of ions that
occurs when an ionic compound dissolves• Dissociation equations show how an ionic
solid breaks into ions when it dissociates.
• Don’t forget to balance the equation or add state of matter symbols.
NaCl (s) Na1+(aq)
+ Cl1-(aq)
CaCl2 (s) Ca2+(aq)
+ 2Cl1-
(aq)
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
6
Dissociation Equations
• CaCl2 gives three ions per formula unit – one calcium and two chlorine.
• When one mole of CaCl2 dissociates…
• One mole of calcium ions are produced• Two moles of chloride ions are produced• Three moles of ions – total- are produced
CaCl2 (s) Ca2+(aq)
+ 2Cl1-
(aq)
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
7
1. Write the equation for the dissolution of aluminum sulfate, Al2(SO4)3 , in water. How many moles of aluminum ions and sulfate ions are produced by dissolving 1 mol of aluminum sulfate? What is the total number of moles of ions produced by dissolving 1 mol of aluminum sulfate?
p. 4
36
Al2(SO4)3 (s) 2Al3+ (aq) + 3SO4 2−(aq)
2 mol aluminum ions, 3 mol sulfate ions
5 ions total
Dissociation Sample Problem
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
8
1. Write the equation for the dissolution of each of the following in water, and then determine the number of moles of each ion produced as well as the total number of moles of ions produced.
a. 1 mol ammonium chloride
b. 1 mol sodium sulfide
c. 0.5 mol barium nitrate
p. 4
36
Dissociation Practice Problems
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
9
a. NH4Cl (s) NH4 1+ (aq) + Cl 1−
(aq)
1 mol ammonium ions; 1 mol chloride ions; 2 mol total ions
b. Na2S (s) 2Na1+ (aq) + S 2−(aq)
2 mol sodium ions; 1 mol sulfide ions; 3 mol total ions
c. Ba(NO3)2 (s) Ba2+ (aq) + 2NO3 1−(aq)
1 mol barium ions; 2 mol nitrate ions; 3 mol total ions
p. 4
36
Dissociation Practice Problems
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
10p. 437
Solubility of Ionic Compounds
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
11p. 437
General Solubility Guidelines
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
12
General Solubility Guidelines
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
13
General Solubility Guidelines
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
14p. 438(NH
4) 2
S +
Cd(N
O3) 2
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
15
NET IONIC EQUATION• Write the balanced equation for the
reaction between ammonium sulfide and cadmium II nitrate. Be sure to include states of matter
• What type of reaction is it? What are the products?(NH4)2S (aq) + Cd(NO3)2 (aq)
2 NH4NO3 (aq) + CdS
(s)
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
16
NET IONIC EQUATION
Each (aq) is dissociated. The (s) is not dissociated; it is the precipitate.Write the dissociation equation for each (aq).(NH4)2S (s) 2 (NH4)1+
(aq) + S2-(aq)
Cd(NO3)2 (s) Cd2+(aq) + 2 NO3
1- (aq)
2 NH4NO3 (aq) 2 NH41+
(aq) + 2 NO31- (aq)
(NH4)2S (aq) + Cd(NO3)2 (aq) 2 NH4NO3 (aq) + CdS
(s)
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
17
NET IONIC EQUATION(NH4)2S (aq) + Cd(NO3)2 (aq) 2 NH4NO3 (aq) + CdS
(s)
(NH4
)S
+ +
Cd
1+ 2-
(aq) (aq)
(NO3
)
2+ 1-
(aq) (aq)
NH4NO3
+ +1+ 1-
(aq) (aq)
2 2 2 2
CdS
+(s)
Break all (aq) into ions; not the (s)
Balance and add states
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
18
NET IONIC EQUATION(NH4)2S (aq) + Cd(NO3)2 (aq) 2 NH4NO3 (aq) + CdS
(s)
(NH4
)S+ + Cd
1+ 2-
(aq) (aq)
(NO3
)
2+ 1-
(aq) (aq)
NH4NO3+ +
1+ 1-
(aq) (aq)
2 2 2 2 CdS+(s)
Identify spectator ions and remove
Write what’s left.
+
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
19
2-
NET IONIC EQUATION(NH4)2S (aq) + Cd(NO3)2 (aq) 2 NH4NO3 (aq) + CdS
(s)
(NH4
)
S
+ +
Cd
1+
(aq)
(aq)
(NO3
)
2+
1-
(aq)
(aq)
NH4NO3+ +
1+ 1-
(aq) (aq)
2 2 2 2
CdS
+
(s)
This is the net ionic equation.
+
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
20
Ag(NO3) + NaCl
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
21
NET IONIC EQUATION• Write the balanced equation for the
reaction between sodium chloride and silver nitrate. Be sure to include states of matter
• What type of reaction is it? What are the products?NaCl (aq)+ Ag(NO3) (aq) NaNO3 (aq)+ AgCl (s)
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
22
NET IONIC EQUATION
Each (aq) is dissociated. The (s) is not dissociated; it is the precipitate.Write the dissociation equation for each (aq).NaCl (s) Na1+
(aq) + Cl1-(aq)
Ag(NO3) (s) Ag1+(aq) + NO3
1- (aq)
NaNO3 (aq) Na1+ (aq) + NO3
1- (aq)
NaCl (aq) + AgNO3 (aq) NaNO3 (aq) + AgCl (s)
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
23
NaCl (aq) + AgNO3 (aq) NaNO3 (aq) + AgCl (s)
NET IONIC EQUATIONN
aCl
+ +
Ag
1+ 1-
(aq) (aq)
NO3
1+ 1-
(aq) (aq)
NaNO3
+ +1+ 1-
(aq) (aq)
AgCl
+(s)
Break all (aq) into ions; not the (s)
Balance and add states
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
24
+
NaCl (aq) + AgNO3 (aq) NaNO3 (aq) + AgCl (s)
NET IONIC EQUATION
Na
Cl+ + Ag1+ 1-
(aq) (aq)
NO31+ 1-
(aq) (aq)
Na
NO3+1+ 1-
(aq) (aq)
AgCl+(s)
Identify spectator ions and remove
Write what’s left.
+
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
25
This is the net ionic equation.
+
NaCl (aq) + AgNO3 (aq) NaNO3 (aq) + AgCl (s)
NET IONIC EQUATION
Na
Cl
+ +
Ag
1+
1-
(aq)
(aq)
NO3
1+
1-
(aq)
(aq)
Na
NO3+1+ 1-
(aq) (aq)
AgCl
+
(s)
+
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
26
2-
NET IONIC EQUATION(NH4)2S (aq) + Cd(NO3)2 (aq) 2 NH4NO3 (aq) + CdS
(s)
(NH4
)
S
+ +
Cd
1+
(aq)
(aq)
(NO3
)2+
1-
(aq)
(aq)
NH4NO3+ +
1+ 1-
(aq) (aq)
2 2 2 2
CdS
+
(s)
This is the net ionic equation.
+
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
27
Identify the precipitate that forms when aqueous solutions of zinc nitrate and ammonium sulfide are combined. Write the equation for the possible double-displacement reaction. Then write the formula equation, overall ionic equation, and net ionic equation for the reaction.
p. 4
40
Zn 2(aq) S 2−(aq) →ZnS (s)
Sample Problem p. 440
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
28
1. Will a precipitate form if solutions of potassium sulfate and barium nitrate are combined? If so, write the net ionic equation for the reaction.
2. Will a precipitate form if solutions of potassium nitrate and magnesium sulfate are combined? If so, write the net ionic equation for the reaction.
p. 4
40
2. No
Practice Problems p. 440
1. Yes; Ba 2(aq) SO4 2−(aq) →BaSO4 (s)
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
29
3. Will a precipitate form if solutions of barium chloride and sodium sulfate are combined? If so, identify the spectator ions and write the net ionic equation.
4. Write the net ionic equation for the precipitation of nickel(II) sulfide.
p. 4
40
4. Ni 2(aq) S 2−(aq) →NiS (s)
Practice Problems p. 440
3. Yes; Naand Cl−; Ba 2(aq) SO4 2−(aq) →BaSO4 (s)
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
30
Ionization vs. Dissociation
• Covalent compounds
• Ions are formed from solute molecules when they dissolve.
• Ionic compounds• Ions are already
present – the ions are separated by the water molecules.
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
31Dis
soci
ati
on &
Ioniz
ati
on
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
32
Ionization• Usually occurs with polar molecules• If the strength of a bond within the solute
molecule is weaker than the attractive forces of the solvent molecules, then the covalent bond of the solute breaks and the molecule is separated into ions.
• The ions are hydrated – just like ions from dissociation.
HCl (g) H1+(aq)
+ Cl1-(aq)
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
33
Hydronium ion, H3O+
• H+ ion does not exist by itself.• H+ ion bonds to a water molecule to form
H3O+, a hydronium ion.
• Better described as a reaction.
H2O (l) + HCl (g)
H3O+(aq) + Cl-(aq)
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
34
• A solution which contains all (or most) of the solute in the form of ions.
• The solute is completely dissociated.
Strong Electrolytes
CaCl2 (s) 1 mole
Ca2+(aq)
+ 2Cl1-
(aq)
1 mole 2 moles+2 -1-1
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
35
• A solution which contains some of the solute in the form of ions, but most of the molecules stay intact.
• The solute is slightly ionized.
Weak Electrolytes
HF (aq) + H2O (l) 1 mole
H3O+(aq)
+ F1-(aq)
0.05 mol 0.05mol
Chapter 13 Section 1 Comp. in Aq. Soln p. 434-445
36p. 442*
Electrolytes
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