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Page 1
CHAPTER 4: REACTIONS
AQUEOUS SOLUBILITY
DISSOLUTION IN WATER
Soluble molecular compounds (with oxygen or nitrogen) in solution…
Soluble ionic compounds (“salts”) in solution…
IONIC SOLUBILITY TRENDS
Grams of solute that dissolve in 100 mL water (25 ˚C)
RbNO3 KCl Li2CO3 Ca(OH)2 BaSO4 Mg3(PO4)2
Solubility g/100 mL H2O
65.0 35.5 1.30 0.160 0.00031 0.00009
CH3CH2OHstir
Water
CH3CH2OH (l)
CH3CH2OH (l)
CH3CH2OH (aq)
stir
Water
NaCl (s)Na+
Cl–
NaCl (aq)
NaCl (s)
Separate into individual molecules
separate intoindividual ions
soluble insoluble
Page 2
Is each compound soluble (aq) or insoluble (s) in water?
CuCl2 (NH4)3PO4 CaSO4
KOH Ba(C2H3O2)2 NiCO3
ELECTROLYTIC SOLUTIONS
CONDUCTIVITY TESTS
IONS ALLOW FOR CONDUCTIVITY
AQUEOUS SOLUBILITY
Salts are Soluble with: (1) Group IA metal ions; (2) Ammonium ions; (3) Nitrates, Nitrites, Chlorates, and Perchlorates; (4) Acetates (except with aluminum and silver); (5) Halogens (except with silver, lead(II), and copper(I) ions); (6) Sulfates (except with barium, calcium, strontium, and lead(II) ions). Salts are Insoluble with (applies only when situations 1-6 are absent): (7) Hydroxides (except with barium); (8) Carbonate, Chromate, Phosphate, and Sulfite ions; (9) Sulfide ions (except with Group IIA metals); (10) Other ions not previously mentioned.
ionicNO NOI CIO 104
a0VNH4
group starts w F
s
Chart go in order rules 1 to until something applies
2TCu Ct rules aq ruler aq rule 6 S
Aq rule 4 aq rules 5
IONS allowfor solutionsto beelectricallyconductive
More ions _more conductive
Page 3
STRONG, WEAK, NON-ELECTROLYTES
Strong Electrolytes Weak Electrolytes Non Electrolytes
Sample Problem:
When sodium carbonate is added to water, the solution is highly conductive. However, when calcium carbonate is added to water, the mixture does not conduct electricity. Explain.
Sugar 12422011
highly conductive weakly conductile non conductivesolutionslots of ion small ions no coin
soluble ionic compound weak acids molecular compounds
NaCl Nat HGH02 GzHaza sugarHGH 02ClHt CzHz0I
strong acid Hcz goinsoluble tonics
Ht CzHg0I
HCl Ht Cl Tithe noions
At Ct TyHt Cl Cacoz
Nazco ions in solution S ble
ACO 0 insoluble
Page 4
STRONG + WEAK ACIDS
PROBLEMS
Sample Problems:
Draw a beaker representation of the major solute component(s) in each aqueous solution. For acids, show several solute particles so as to distinguish between weak and strong acids.
HClO4 (aq) HC3H5O2 (aq) C6H12O6 (aq)
Strong Acids:
HCl, HBr, HI
HNO3, H2SO4
HClO3, HClO4
Weak Acids:
HF, HC2H3O2
H2CO3, H3PO4
many others
strong acid forms 1007 loins
HNOz aq 0 Ht as t NO aa
weak acid only partially ionizeHF oral 0 Ht ag t F as
v little
Ht 104 HC HsOz641206
Ht 104 HGH502Ht cloy Ht C3h502
Strong acid weak acid molecularnon electrolytes
Page 5
Sample Problem: Solutions of the following compounds are made by dissolving 0.5 mole solute in 500 mL water. Rank the resulting aqueous solutions in order of increasing conductivity. NaHCO3 CH3OH H3PO4 BaCl2
PRECIPITATION REACTIONS
WRITING FORMULA EQUATIONS
Formula Equation:
Na2CrO4 (aq) + AgNO3 (aq) →
→
Na2CrO4 (aq) AgNO3 (aq) Product mixture
Yellow Na2CrO4
Red solid
Clear AgNO3
“Black Smokers” Dissolved iron(II) sulfide emitted underwater from hydrothermal vents, which solidify when they cool to form large black chimneys.
H I H
Least CH OH L H POLI L NaHCo Back MO't
molecular weak acidmakes no ions few ion Both are soluble Ionics
Conductive
Nat HCO Ba Cl Cl
2 tons 3 ions
2 aq solidprecipitate
write eachreagent in neutral form
2 AgzCr04 s t 2NaN0z as
NµaaI Cr042 Agt NOB not Naz N 372Agt N 5
Nat NogNatcroup Agt Nos Nat Nog
Nat Agt No TAEK
Page 6
Sample Problem:
Write the balanced formula equation for this reaction. Include phase descriptors (s, l, g, aq).
FeCl3 (aq) + Ca(OH)2 (aq) →
COMPLETE IONIC AND NET IONIC EQUATIONS
For this balanced equation:
Pb(NO2)2 (aq) + 2 NH4I (aq) → PbI2 (s) + 2 NH4NO2 (aq)
Complete Ionic Equation:
Net Ionic Equation:
Sample Problems:
Write the balanced formula equation and net ionic equation for this reaction:
Formula Eqn: AgNO3 (aq) + MgBr2 (aq) →
Net Ionic Eqn:
Write these equations for this reaction (done previously): FeCl3 (aq) + Ca(OH)2 (aq) →
Complete Ionic Eqn:
Net Ionic Eqn:
2 3 3CaClzlaHt2Fe OH s
FestCf CaZtOHCI OHCI
describe reality Write strongelectrolytes as separate ions
Pb aa 2 aah t 2 14 aq ZI laal
PbIz s t 2N Cag t 2 as
remove spectator coins those not involvedin charge
Pb ag t 2I ag PbIz s
Fe as 6 011 as Fecott s
reduce if possible
Page 7
ACID-BASE REACTIONS
Acid Reflux Effect of acid rain on marble statues Acids and bases reacting
EQUATIONS
STRONG ACIDS
Formula Equation: HCl (aq) + KOH (aq) →
Complete Ionic Equation:
Net Ionic Equation:
WEAK ACIDS
Formula Equation: H3C6H5O7 (aq) + NaOH (aq) →
Complete Ionic Equation:
Net Ionic Equation:
KCI aa t H2O etCl Kt
Ht ag OH as H2O e
Ht 33 Naz 645076 t3h20 e
Ht 611507 Nat OHHt V
ykeepweak acid in tact
H3C6HsOzlag t 7Na as t 3OH as
3 as t Colts073 as t 3h20 e
HzC6HsOz as t 3OH as C6Hs0I as t3H2O'll
Net lone diff wk vi strong
Page 8
Sample Problems:
Write the balanced formula equation for this reaction:
H2SO4 (aq) + NaOH (aq) →
Which is the net ionic equation for: HNO2 (aq) + CsOH (aq) → CsNO2 (aq) + H2O (l)
A: H+ (aq) + OH– (aq) → H2O (l)
B: HNO2 (aq) + OH– (aq) → H2O (l)
C: HNO2 (aq) + OH– (aq) → NO2– (aq) + H2O (l)
D: HNO2 (aq) + Cs+ (aq) + OH– (aq) → Cs+ (aq) + NO2– (aq) + H2O (l)
CARBONATES
Formula Equation: HCl (aq) + NaHCO3 (aq) →
Formula Equation: HNO3 (aq) + K2CO3 (aq) →
SOLUTION CONCENTRATION
GENERAL IDEA
Aqueous solutions of Cu(NO3)2
Chalk (CaCO3) reacts with vinegar to form bubbles. Limestone, marble (CaCO3) reacts with acidic solutions.
2 Naz504 as t 2h20 e
HtHt5042 NatOHwk acid
I 1Stands
ofNaCl ag t HzCO3
Ht Cl Nat Hoo carbonicI acidH2Oe CO2 s
2 KNO ag t H2O e tC0zgHt NO5 CO HzCOzHt N
MolaritessoluteM
Incentraleddilute
1M 0.05M
Page 9
MOLARITY CALCULATIONS
Sample Problems:
Into a volumetric flask is placed 2.62 g BaCl2 and enough water to make 25.0 mL of solution. What is the molarity of the BaCl2 solution?
Molarity is also a conversion factor:
How many grams of H2SO4 are present in 50.00 mL of 6.00 M H2SO4?
What volume of 1.09 M NaCl contains 0.075 mol of NaCl?
Mass Moles Volume
2.62g Bafta M mo aCksolution
25h0 2.62g Back 0 04,26
q137.33 2135.45
208.2351mi
M 0.0126mLI 0.0250 L25.0mL too O50p3acY
M.V notMM Molarity
Moyle 4 mot
not 1L50.00mF X za 4 it I
6oomf 9
gym
24.01 t 32.06 4 16.00
0.075hut 0.069T1 09 mot
Page 10
DILUTION
Diluting Liquids: Which has more alcohol?
Shot of whiskey
Whiskey sour:
1 shot of whiskey 1 tsp. lime juice
3.75 oz. sweet + sour mix
Sample Problems:
When 30.0 mL of blood is diluted to 1.000 L, the concentration of NaCl is 0.00474 M. What is the concentration of NaCl in the original blood sample?
250.0 mL of water is added to 25.0 mL of a 0.750 M MgF2 solution. What is the concentration of fluoride ions in the resulting solution?
Dilution motbefore mot after M Y Mz
needsconsistent
V 30.0mL Milli M2V2 f units
VII OWL M Mj 4 10.15871Mj 0.00474M 0.0300 C
sM30.0hL
nµ
250 I
tf iMN MzVz
Mz M V 0,750M 25.0mLI 275.0mL
MgFz 0 Mg2t t 2F 0.0682 M MgFz
0.0682 mot 5 10.136Mt