1 types of chemical reactions and solution stoichiometry chapter 4
TRANSCRIPT
1
Types of Chemical Reactions Types of Chemical Reactions and Solution Stoichiometryand Solution StoichiometryChapter 4Chapter 4
2
Water, the Common Water, the Common SolventSolvent
Section 4.1Section 4.1
3
• Type of bond?
• Shape?
• Polarity?
Nature of WaterNature of Water
Covalent
Polar
Bent/Angular
4
• Ionic solids that dissolve are soluble.• Ionic solids will dissolve in polar solvents
but not nonpolar solvents• Water molecules break the crystal lattice
into separate ions. This is dissociation.• Then the water molecules surround the
ions. This is hydration. • Ionic solids that do not dissolve are
insoluble.
Ionic Solute-Solvent Ionic Solute-Solvent InteractionInteraction
5p. 411
Ion
ic S
olu
te-S
olv
en
t In
tera
cti
on
Ion
ic S
olu
te-S
olv
en
t In
tera
cti
on
6Solu
bilit
y o
f C
om
pou
nd
sS
olu
bilit
y o
f C
om
pou
nd
s
notes
7Solu
bilit
y o
f C
om
pou
nd
sS
olu
bilit
y o
f C
om
pou
nd
s
notes
8
• Miscible – Liquids that dissolve freely in one another in any proportion.
• Immiscible – Liquids that are not soluble in each other.
• “Likes dissolve likes”Polar solutes dissolve in polar
solvents.Nonpolar solutes dissolve in
nonpolar solvents.• Alcohols are slightly polar.
Liquid Solute-Solvent Liquid Solute-Solvent InteractionInteraction
9Mis
cib
le a
nd
Im
mis
cib
leM
iscib
le a
nd
Im
mis
cib
le
10p. 412
Immiscible & MiscibleImmiscible & Miscible
11
The Nature of Aqueous The Nature of Aqueous SolutionsSolutions
Section 4.2Section 4.2
12
• A homogeneous mixture of two or more substances in a single phase
• Particles are thoroughly mixed and remains mixed indefinitely
• Components of a solution– Solvent: does the dissolving; the larger
amount– Solute: is being dissolved; the smaller
amount
SolutionSolution
13p. 406
Electric Conductivity in Electric Conductivity in SolutionsSolutions
14
• Electrolyte – a substance that dissolves in water to give a solution that conducts electric current
• Nonelectrolytes – a substance that dissolves in water to give a
solution that does not conduct electricity– Does not produce ions– Example: sugar and ethanol
Electrolytes & Electrolytes & NonelectrolytesNonelectrolytes
15
• Completely ionized when they are dissolved in water
• Three classes– Soluble Salts
– Strong Acids: produce H+ ions when dissolved in water•HCl (g) + H2O (l) H3O+ (aq) + Cl- (aq)
– Strong Bases: produce OH- ions when dissolved in water•NaOH (s) Na+ (aq) + OH- (aq)
Strong ElectrolytesStrong Electrolytes
NaCl (s) Na1+(aq)
+ Cl1-(aq)
16
An acid that ionizes completely in aqueous solution.
STRONG ACID LISTHCl hydrochloric acidHI hydroiodic acidHBr hydrobromic acidH2SO4 sulfuric acidHNO3 nitric acidHClO3 chloric acidHClO4 perchloric acid
Strong AcidsStrong Acids
MEMORIZE!
MEMORIZE!
17
Strong Bases – bases that dissociate completely – strong electrolytes
Formed from Group I & II metalscombined with hydroxide
Strong BasesStrong Bases
18
• Substances that exhibit a small degree of ionization in water
• Two classes– Weak Acids: produce few H+ ions when
dissolved in water
CH3COOH(aq) + H2O(l) CH3COO-(aq) + H3O+
(aq)
– Weak Bases: produce few OH- ions when dissolved in waterNH3 (aq) + H2O (l) NH4
+ (aq) + OH-(aq)
Weak ElectrolytesWeak Electrolytes
19
The Composition of The Composition of SolutionsSolutions
Section 4.3Section 4.3
20
The number of moles of solute in one liter of solution.
MolarityMolarity
MM = =moles of solutemoles of solute
liters of solutionliters of solution
MM = =molmol
LL
21
1. Calculate the molarity of a solution prepared by dissolving 11.5 g of solid NaOH in enough water to make 1.50 L of solution.
2. Give the concentrations of each type of ion in the following solutions:a. 0.50 M Co(NO3)2
b. 1 M Fe(ClO4)3
3. Calculate the number of moles of chloride ions in 1.75 L of 1.0 x 10-3 M ZnCl2.
4. Typical blood serum is about 0.14 M NaCl. What volume of blood contains 1.0 mg NaCl?
Molarity Practice ProblemsMolarity Practice Problems
22
• A solution whose concentration is accurately known.– To analyze the alcohol content of a certain
wine, a chemist needs 1.00 L of an aqueous 0.200 M K2Cr2O7 solution. How much solid potassium dichromate must be weighed out to make this solution?
Standard SolutionStandard Solution
23
• A solution in concentrated form.• Dilution: process where water is added
to achieve the molarity desired for a particular solution.
• If the mole ratio is 1:1, then M1V1=M2V2 can be used– What volume of 16 M sulfuric acid must be
used to prepare 1.5 L of a 0.10 M sulfuric acid solution?
DilutionDilution
24
Precipitation ReactionsPrecipitation Reactions
Section 4.5Section 4.5
25
• Two solutions mix and an insoluble solid forms
• The solid that forms is called a precipitate.
• Predicting Reaction Products:– Using the solubility rules, predict what will
happen when the following pairs of solutions are mixed.• Potassium nitrate and barium chloride• Sodium sulfate and lead (II) nitrate• Potassium hydroxide and iron (III) nitrate
Precipitation ReactionsPrecipitation Reactions
26
Describing Reactions in Describing Reactions in SolutionSolution
Section 4.6Section 4.6
27
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)
28
NET IONIC EQUATION
Each (aq) is dissociated. The (s) is not dissociated; it is the precipitate.
(NH4)2S (aq) + Cd(NO3)2 (aq) 2 NH4NO3 (aq) + CdS
(s)
29
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
30
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.
+
31
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.
+
32
Ag(NO3) + NaCl
33
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)
34
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
35
+
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.
+
36
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)
+
37
Stoichiometry of Stoichiometry of Precipitation ReactionsPrecipitation Reactions
Section 4.7Section 4.7
38
1. When aqueous solutions of sodium sulfate and lead (II) nitrate are mixed, lead (II) sulfate precipitates. Calculate the mass of lead (II) sulfate formed when 1.25 L of 0.0500 M lead (II) nitrate and 2.00 L of 0.0250 M sodium sulfate are mixed.
Determining the mass of Determining the mass of product formedproduct formed
39
Acid-Base ReactionsAcid-Base Reactions
Section 4.8Section 4.8
40
Brønsted-Lowry Acid & BaseBrønsted-Lowry Acid & Base
H
NH3(aq) + H2O(l) NH4+
(aq) + OH-
(aq)N
H
O
HH N HH
H +
OH-
HH
A molecule
or ion that is a proton
donorACID
A molecule or ion that is a proton acceptor
BASE
41
The reaction of hydronium ions and hydroxide ions to form water molecules.
Neutralization ReactionsNeutralization Reactions
HCl(aq) + NaOH(aq) NaCl(aq) + HOH(l)
ACID + BASE SALT + WATER
H++Cl- + Na++OH- Na++Cl- + HOH
H+ (aq)
+ OH- (aq) HOH (l)
42
The reaction of hydronium ions and hydroxide ions to form water molecules.
Neutralization ReactionsNeutralization Reactions
HC2H3O2 (aq) + KOH(aq) KC2H3O2(aq) + HOH(l)
ACID + BASE SALT + WATER
HC2H3O2 + K++OH- K++C2H3O2-1+ HOH
HC2H3O2(aq) + OH-
(aq) HOH (l) + C2H3O2
-1(aq)
43
1. What volume of a 0.100 M HCl solution is needed to neutralize 25.0 mL of 0.350 M NaOH?
2. In a certain experiment, 28.0 mL of 0.250 M HNO3 and 53.0 mL of 0.320 M KOH are mixed. Calculate the amount of water formed in the resulting reaction. What is the concentration of H+ and OH- ions in excess after the reaction goes to completion.
Neutralization ReactionsNeutralization Reactions
44
• Delivery from a buret of a measured volume of a solution of known concentration (the titrant) into a solution containing the substance to be analyzed (the analyte)
• Equivalence point: the point in a titration where enough titrant has been added to react exactly with the analyte
• Endpoint: The point where the indicator actually changes color
Acid-Base TitrationAcid-Base Titration
45
1. A student weighs out a 1.3009 g sample of KHC8H4O4 . KHP has one acidic hydrogen. The student dissolves the KHP in distilled water, adds phenolpthalein and titrates the solution with sodium hydroxide to the endpoint. The difference between the final and initial buret readings indicates that 41.20 ML of the sodium hydroxide is required to react exactly with the KHP. Calculate the concentration of sodium hydroxide.
Neutralization Neutralization Titration/AnalysisTitration/Analysis
46
2. An environmental chemist analyzed the effluent from an industrial process known to produce the compounds CCl4 and HC7H5O2, a weak acid with one acidic hydrogen. A sample of the effluent weighing 0.3518 g was shaken with water and the resulting aqueous solution required 10.59 mL of 0.1546 M NaOH for neutralization. Calculate the mass percent of HC7H5O2 in the original sample.
Neutralization Neutralization Titration/AnalysisTitration/Analysis