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