PowerPoint to accompany Chapter 3 Aqueous Reactions and Solution Stoichiometry.
Reactions in Aqueous Solutions Solution Stoichiometry · Reactions in Aqueous Solutions & Solution...
Transcript of Reactions in Aqueous Solutions Solution Stoichiometry · Reactions in Aqueous Solutions & Solution...
Chapter 4
Reactions in
Aqueous Solutions
&
Solution Stoichiometry
WHAT IS A SOLUTION ?
1. A HOMOGENEOUS Mixture of _______ or MORE Substances
Solvent + Solute = Solution
2. __________ varies
Reactions in Solution
• NEUTRALIZATION (Acid + _____)
• PRECIPITATION REACTIONS
• OXIDATION REDUCTION (______)
Acid Base Reaction
Example 1:
Hydrochloric Acid reacts with Sodium Hydroxide
1st Write the Reaction
HCl(aq) + NaOH(aq) � H2O + NaCl(aq)
2nd Balance Reaction
3rd Interpret Reaction
1 HCl (aq) +1 NaOH (aq) � H2O +1 NaCl (aq)
What is in solution?
1. HCl(aq) : HCl and ______
2. NaOH(aq) : NaOH and _____
What is reacting with what ?
HCl and ______
NOT THE WATER
Acid Base Reaction
Example 2:
Sulfuric Acid + Magnesium Hydroxide
1st Write the Reaction
H2SO4(aq) + Mg(OH)2(aq) � H2O + a salt
What is the salt ?
________= Magnesium Sulfate
H2SO4(aq) + Mg(OH)2(aq)�H2O + MgSO4(aq)
Is the reaction BALANCED ?
1 H2SO4(aq) +1 Mg(OH)2(aq)� __ H2O + 1 MgSO4(aq)
2nd Interpret the reaction
What is reacting with what ?
H2SO4 and Mg(OH)2 NOT the ______
What is an AQUEOUS Solution ?
WATER and ????? {see Table 4.1} SOLUBILITY RULES
WHAT IS IN SOLUTION ?
Molecules
or
Ions ?
Soluble Salts :: Solubility Rules
1. ALL Alkali Metals and Ammonium
Salts are SOLUBLE.
2. ALL Nitrates, PerChlorates and
Acetates are SOLUBLE
Now For The “Sometimes”
3. All Chlorides, Bromides, Iodides Soluble
EXCEPT Silver, Mercury, & Lead
4. See Text for Sulfates, Carbonates, etc.
ELECTROLYTE – A substance that dissolves
in water to produce IONS
Examples: HCl(aq), NaOH(aq), NaCl(aq)
NON ELECTROLYTE - A substance that Does
NOT produce IONS in water.
They remain as MOLECULES.
Examples: sugar, ethylene glycol
1. STRONG Electrolytes
A substance that completely _______
Strong Acids, Strong Bases, Soluble Salts
2. WEAK Electrolytes
Substance that does _____ completely ionize
Weak Acids, Weak Bases, SS Salts
ACIDS
Strong Acids
HCl(aq) � H+ (aq) + Cl- (aq) 100%
Weak Acids
HF(aq) ↔ H+ (aq) + ? - (aq)
note H+ (aq) ≡ H3O+ HYDRONIUM ION
ELECTROLYTESELECTROLYTESELECTROLYTESELECTROLYTES
1. STRONG ELECTROLYTES
Strong Acids [7]
Strong Bases [7]
Soluble Salts
2. WEAK ELECTROLYTES
Weak Acids / Bases
Slightly Soluble Salts
The 7 STRONG Acids
1. HCl(aq) ..……Hydrochloric Acid
2. HBr(aq)….…..Hydrobromic Acid
3. HI(aq)………..Hydroiodic Acid
4. HNO3(aq)…….Nitric Acid
5. H2SO4(aq)…….Sulfuric Acid
6. HClO3(aq)…….Chloric Acid
7. HClO4(aq)…….PerChloric Acid
ARRHENIUSARRHENIUSARRHENIUS BASES
1. STRONG Bases
NaOH (aq) � Na+ (aq) + OH- (aq) 100%
2. WEAK Bases
NH4OH(aq) ↔ NH4+ (aq) + ? - (aq)
note NH4OH ≡ NH3 (aq)
The 7 STRONG Bases
1. LiOH(aq)…….Lithium Hydroxide
2. NaOH(aq)……Sodium Hydroxide
3. KOH(aq)……..Potassium Hydroxide
4. RbOH(aq)……Rubidium Hydroxide
5. CsOH(aq)……Cesium Hydroxide
6. Ba(OH)2(aq)….Barium Hydroxide
7. Sr(OH)2(aq)…..Strontium Hydroxide
What do the following compounds do when
mixed with water ?
Magnesium Iodide
Aluminum Nitrate
Ammonium Sulfate
Perchloric Acid
Silver Chloride
MgI2 � Mg2+(aq) + ? I-(aq)
Al(NO3)3 � Al3+(aq) + ? NO3-(aq)
(NH4)2SO4� ? NH4+(aq) + SO4
2-(aq)
HClO4 � H+(aq) + ClO4-(aq)
??????????????????
1. Precipitation Reaction
2. Acid-Base Reaction
3. Oxidation-Reduction
Reaction
4. Active Metal + Acid
An INSOLUBLE Solid is Formed
Slightly IONIZED
Substance Formed
Change in Oxidation
State
A Gas is Formed
How do you recognize a PRECIPITATION
Reaction ?
INSOLUBLE SOLID FORMED
For example :
AgCl formed in reaction:
AgNO3 (aq) + NaCl (aq) � AgCl (s) + NaNO3 (aq)
1. Precipitation Reaction
2. Acid-Base Reaction
3. Oxidation-Reduction
Reaction
4. Active Metal + Acid
Insoluble Solid Formed
Slightly IONIZED
Substance Formed
Change in Oxidation
State
A Gas is Formed
ACID BASE REACTION ?
WATER IS FORMED
HCl (aq) + NaOH (aq) � H2O + NaCl (aq)
1. Precipitation Reaction
2. Acid-Base
3. Oxidation-Reduction
Reaction
4. Active Metal + Acid
Insoluble Solid Formed
Slightly IONIZED
Substance Formed
Change in Oxidation
State
A Gas is Formed
How do you recognize an
Oxidation Reduction Reaction ?
CHANGE IN OXIDATION STATE
MUST KNOW OXIDATION “RULES”
See Page 139 – 140 Text
1. Precipitation Reaction
2. Acid-Base Reaction
3. Oxidation-Reduction
Reaction
4. Active Metal
+ Acid
An INSOLUBLE Solid is Formed
Slightly IONIZED
Substance Formed
Change in Oxidation
State
A Gas is Formed
Active Metal + Acid Reaction
Hydrochloric acid reacts with zinc metal to
produce Hydrogen gas and zinc chloride
1st Write Reaction
Zn (solid) + HCl (aq) → ___ (gas) + ____(aq)
2nd Balance Reaction
1 Zn (s) + 2 HCl (aq) → 1 H2 (g) + 1 ZnCl2(aq)
3rd Interpret Reaction
1 mol Zn needed for every 2 moles of HCl
forming 1 mol H2 and 1 mol ZnCl2
How much HCl(aq) is need to convert 65.4 g of
Zn to hydrogen gas and zinc chloride?
How many moles of Zn are present ?
How many moles of HCl are required ?
From: 1 Zn + 2 HCl (aq)→ H2+ ZnCl2(aq)
2 x 1.00 = _____ moles HCl needed
.001 39.65
1 x 4.65 =
grams
molesgrams
MOLECULAR WEIGHTMOLECULAR WEIGHTMOLECULAR WEIGHT
is the CONVERSION FACTORBetween
MOLES of a Solid
and
The WEIGHT of the Solid
( ) MolesGrams
MolesGrams =×
?
1___
How much HCl(aq) is need to convert 6.54 g of
Zn to hydrogen gas and zinc chloride?
How many moles of Zn are present ?
How many moles of HCl are required ?
From: 1 Zn + 2 HCl (aq)→ H2+ ZnCl2(aq)
2 x 0.100 = ____ moles HCl needed
0010. 39.65
1 x 54.6 =
grams
molesgrams
How much HCl(aq) is need to convert 10.0g of
Zn to hydrogen gas and zinc chloride?
How many moles of Zn are present ?
How many moles of HCl are required ?
From: 1 Zn + 2 HCl (aq)→ H2+ ZnCl2(aq)
2 x 0.153 = ____ moles HCl needed
153.0 39.65
1 x 0.10 =
grams
molesgrams
What volume of 2.50 M HCl(aq) is needed to convert 10.0 g of Zn to zinc chloride ?
CONCENTRATIONS IN SOLUTIONS
Molarity
MOLARITY is a
CONVERSION FACTORCONVERSION FACTORCONVERSION FACTORCONVERSION FACTOR
BETWEEN
NUMBER OF MOLES OF SOLUTE
AND
THE VOLUME OF SOLUTION
Molarity (M)
Memorize the definition
Molarity = Moles of Solute
Liters of Solution
or
Moles Solute = Molarity x Volume
1 Zn + 2 HCl (aq)→ H2+ ZnCl2(aq)( 2.50 M HCl(aq) )
For HCl(aq) need 2 x 0.153 = 0.306 moles
Molarity x Volume = moles
mLMolarity
molesvolume 122
50.2
306.0 ===
LIMITING REAGENT ?LIMITING REAGENT ?LIMITING REAGENT ?
1 Zn + 2 HCl (aq)→ H2+ ZnCl2(aq)
What is the limiting reagent if 122 mL of 2.50 M HCl(aq) is combined with 10.0 g of Zn to zinc chloride ?
(a) Zn
(b) Water
(c) HCl
(d) There isn’t one
Limiting Reagent
What is the limiting reagent if 122 mL
of 2.50 M HCl(aq) is combined with
1.0 g of Zn to zinc chloride ?
(a)Zn
(b)Water
(c) HCl
(d) There isn’t one
Limiting Reagent
What is the limiting reagent if 125 mL
of 2.50 M HCl(aq) is combined with
10.0 g of Zn to zinc chloride ?
(a)Zn
(b)water
(c) HCl
(d) There isn’t one
Limiting Reagent
What is the limiting reagent if 122 mL
of 2.50 M HCl(aq) is combined with
20.0 g of Zn to zinc chloride ?
(a)Zn
(b)water
(c) HCl
(d) There isn’t one
Limiting Reagent
What is the limiting reagent if 120 mL
of 2.50 M HCl(aq) is combined with
10.0 g of Zn to zinc chloride ?
(a)Zn
(b)water
(c) HCl
(d) There isn’t one
OXIDATION REDUCTION (Redox) REACTIONS
Examples
HgO(s) � Hg(liq) + O2 (gas)
Fe(s) + O2(gas) → Fe
2O
3(s)
Zn(s) + HCl(aq) → H2(g) + ZnCl
2(aq)
How do you recognize an
Oxidation Reduction Reaction ?
MUST KNOW OXIDATION “RULES”
See Page 139 – 140 Text
1. EACH ATOM in a PURE ELEMENT
Has An OXIDATION NUMBER of
ZERO
. 2. For IONS Consisting of a SINGLE
ATOM, the Ox Num IS EQUAL
To THE CHARGE ON THE ION
3. F ALWAYS Has an Ox Num of –1
In ALL Of Its COMPOUNDS
4. Cl, Br, and I are – 1 EXCEPT when
combined with O or F
5. H is + 1 and O is – 2 EXCEPT in
Hydrides (CaH2) & Peroxides (H2O2)
6 The ALGEBRAIC SUM of the Oxidation
Numbers in a NEUTRAL Compound
MUST be ZERO
Prob 4.40 Determine the oxidation number for
1. Ti in TiO2
2. Sn in SnCl2
3. C in C2O42-
4. N in (NH4)2SO4
5. N in HNO3
6. Cr in Cr2O72-
____
____
____
____
____
____
OXIDATION Number of Underlined Atom
1. O 2
2. H2 O
3. H2 O 2
4. KClO 4
5. H 2
6. HCl
7. CaH 2
8. H 2O 2
____
____
____
____
____
____
____
____
OXIDATION Number of Underlined Atom
1 H Cl O4
2. Cl O3-
3. Cl F
4. Cl 2
____
____
____
____
For Redox Reactions
• What is The OXIDATION NUMBER
For EACH Element Present ?
• What is OXIDIZED ?
• What is REDUCED ?
• What is The OXIDIZING AGENT ?
• What is The REDUCING AGENT ?
1. OXIDATION – LOSS of electrons
2. REDUCTION – GAIN of electrons
• AN OXIDIZING AGENT “CAUSES”
OXIDATION
• A REDUCING AGENT “CAUSES”
REDUCTION
Zn(s) + 2 HCl(aq) → H2(g) + ZnCl2(aq)
What is The OXIDATION NUMBER For
EACH Element Present ?
What is OXIDIZED ? ________
What is REDUCED ? ________
What is the Oxidizing AGENT ? ________
What is the Reducing AGENT ? ________
Classify Each Reaction As Either(a) Precipitation, (b) Neutralization or
(c) Oxidation-Reduction
Hg(NO3)2(aq) + NaI(aq) � NaNO3(aq) + HgI2(S)
H3PO4(aq) + KOH(aq) � H2O(liq) + K3 PO4(aq)
HgO(s) + heat � Hg(liq) + O2 (gas)
CH4(gas) + O2 (gas) � CO2(gas) + H2O(liq)
How do you recognize a
Precipitation Reaction ?
INSOLUBLE SOLID FORMED
Will the following reaction occur ?
A solution of Silver Nitrate is mixed
with a solution of Sodium Chloride
_______ ?
How do you know ?
______ formed in reaction:
AgNO3 (aq) + NaCl (aq) � _____(s) + NaNO3 (aq)
Will the following reaction occur ?
NaOH(aq) + HClO4(aq) � ??
______
How do you know ?
______ formed in reaction
Will the following reaction occur ?
Pb(NO3)2 + Na2SO4 � ??
_______ ?
How do you know ?
______ formed in reaction:
Will the following reaction occur ?
AgClO4 + Na2S → ??
_______ ?
How do you know ?
______ formed in reaction:
Will the following reaction occur ?
AgClO4 + NaNO3 → ??
_______ ?
How do you know ?
______ formed in reaction:
• MOLECULARMOLECULARMOLECULARMOLECULAR Uses The Full Formula
Of Reactants and Products
• IONIC IONIC IONIC IONIC – A Reaction Written So Ions
Are Explicitly Shown
• NET IONICNET IONICNET IONICNET IONIC – Spectator Ions Are
Removed From Ionic Equation
Write & Balance Molecular, Ionic
And Net Ionic Equations For :
Hg(NO3)2(aq) + NaI(aq) � ?????????????
H2SO4(aq) + KOH(aq) � ???????????????
CH4(gas) + O2 (gas) � ??????????????
Preparing Solutions
1. Preparing Solutions of Known Concentrations
2. Preparing a Solution by Dilution
How Many Moles Of each of the following
are Needed To Make 1.O Liter of 1.0 M
Solution ?
KCl ; NaHCO3 ; Na2CO3 ;Fe2O3
How Many Moles Of each of the above are Needed To Make 1.O Liter of 1.5 M Solutions ?
How Many MOLES Of Na2CO3
Needed To Make 2.O Liters of 1.5 M Solution ?
• Need 1.5 Moles of Na2CO
3to make one Liter
of 1.5 M
• ???????????????????????????
• So Need 2 x 1.5 Moles = 3.0 Moles to make
2.0 Liters
How Many GRAMSGRAMSGRAMSGRAMS Of Na2CO3 Are
Needed To Make 2.O L Of 1.5 M Solution
1st : How many moles ?
2nd : How do you go from moles to grams?
What is formula Weight for Na2CO
3 ?
2 x 23 + 12 + 3 x 16 = 106 g / mole
3.0 moles x 106 g / mole = (318g)
Preparing Solutions of Known Concentrations
An experiment requires ½ Liter of a
0.0200 M solution of Na2 CO3
You are given a bottle of solid Na2 CO3
some distilled water, and a 500 mL
volumetric flask. Describe how to
make the required solution.
Molarity x Volume = moles
Need ½ Liter of a 0.0200 Molar solution
Molarity x Volume = moles of Solute
(0.0200 M)(0.500 Liters) = 1.00 x 10-2 moles of Na2 CO3
How do you convert from moles to grams?
Formula weight of Na2 CO3 = 106.0 g / mole
(1.00 x 10-2 moles) x (106.0 g / mole) = 1.06 grams
So what do you do?
1. Weigh 1.06 grams of Na2 CO3
2. Transfer the Na2 CO3 to the flask
3. Add water until 500 mL is obtained
Preparing a Solution by Dilution
• An experiment calls for you to use 250
mL of 1.00 M NaOH, but you are given
a large bottle of 2.00 M NaOH.
• Describe how to make the 1.00 M
NaOH solution.
Preparing a Solution by Dilution
• Need 250 mL of 1.00 M NaOH
• Given a large bottle of 2.00 M NaOH.
• How do you make a 1.00 M NaOH solution.
M1 V1 = M2 V2 = moles of Solute
(250 mL) (1.00 M ) = ( ? mL ) (2.00 M )
Volume = 125 mL of 2.00 M NaOH
So what do you do?
1. Measure 125 mL of 2.00 M NaOH
2. Add water until 250 mL is obtained