The Solution Process Edward A. Mottel Department of Chemistry Rose-Hulman Institute of Technology.

The Solution ProcessEdward A. Mottel

Department of Chemistry

Rose-Hulman Institute of Technology

04/18/23

Solutions

Reading assignment:• Zumdahl: Chapter 4.1-4.3, 17.2

Atomic level perspective Molecular versus Ionization Solution concentrations

C C

CH2OH

HO

H

H

O

C

H

C

HO

HOHC

H

OC

CH2OHO

CH

CH2OHC

HO

H

C

HO

H

sucroseC12H22O11

OHH

OHH

OHH

OHH

OHH

OHH

OHH

OHH

OHH

OHH

OHH

sucrose(s) + H2O(l) sucrose(aq)

Water

O

HH • •

 • • • •

 • • O

HH

water has a nonlinear structure(bent molecule)

water has a dipole (polar)

-

++

Polar bonds form when elements of differentelectronegativity bond together.

OH

H-

++

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Electronegative Elements

N, O, F

S, Cl

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Where would hydrogen belong in the periodic table,if the table was organized by period and electronegativity?

C C

CH2OH

HO

H

H

O

C

H

C

HO

HOHC

H

OC

CH2OHO

CH

CH2OHC

HO

H

C

HO

HOHH

OHH

OHH

OHH

OHH

OHH

sucrose(aq)

A hydrogen bonds forms when hydrogen bridgesbetween two very electronegative elements.

intermolecular bonds

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-

OHH

OHH

OHH

OHH

OHH

OHH

OHH

OHH

+

OHH

OH

H

OH

H

OHH

NaCl(s) + H2O(l) Na+(aq) + Cl-(aq)

rock salt

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Ionic BondsElectrostatic Attraction

Na+

Cl – • • •

 •

 • • • •

E = k · q1 · q2

d

Compounds with ionic bonds generally havehigh melting points.

OH

H-

++

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Some Salts are Soluble

Solubility depends on temperature and the solvent

Soluble salts• Group IA, NH4

+, NO3–, CH3COO–, ClO3

–, ClO4–

• Most halides (Cl–, Br–, I–)· except Ag+, Cu+, Hg2

2+, Pb2+, Tl+ • Most sulfates

· except CaSO4, SrSO4, BaSO4, Ag2SO4, HgSO4, PbSO4

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Things to Think About whenWriting a Chemical Equation.

What is the formula of the reactant & product?

What is the phase of the reactant & product? Does it dissolve?

• What would you observe?• How could you predict it?

Write an equation for what occurs whensolid sodium hydrogen carbonate

is mixed with water.

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Solid Sodium Hydrogen Carbonate is Mixed with Water

NaHCO3(s) NaHCO3 (aq)

NaHCO3 (s) Na+(aq) + HCO3–

(aq)

How could you tell?

Does it ionize?

NaHCO3 (s) Na+(aq) + H+(aq) + CO32–

(aq)

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Solid Sodium Hydrogen Carbonate is Mixed with Water

NaHCO3 (s) Na+(aq) + HCO3–

(aq)

Compounds which break into ions and conductelectricity are called electrolytes.

When a salt dissolves,it breaks into its named ions.

What ions form when the following salts dissolve?

calcium acetate

lead(II) nitrate

K2SO4

CuCl2

Write an equation for the dissolution of each ofthe above compounds in water.

When a salt dissolves,it breaks into its named ions.

Ca(CH3COO)2(s) Ca2+(aq) + 2 CH3COO–(aq)

Pb(NO3)2(s) Pb2+(aq) + 2 NO3–(aq)

K2SO4(s) 2 K+(aq) + SO42–(aq)

CuCl2(s) Cu2+( aq) + 2 Cl–(aq)

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Some Salts are Not Very Soluble

Sparingly soluble salts• Most hydroxides

· except Group IA, Ba(OH)2• Sulfides

· except Group IA, Group IIA, NH4+

• Carbonates, phosphates, sulfites

· except Group IA, NH4+

Reactions can occur when solutions containingdifferent ions are mixed.

An aqueous solution of calcium acetateis mixed with an aqueous solution of

potassium sulfate.

Ca2+(aq)

CH3COO–(aq)

K+(aq)

SO42–(aq)

double displacement reaction

Ca2+(aq) + 2 CH3COO– (aq) + 2 K+(aq) + SO4

2–(aq)

CaSO4(s) + 2 K+(aq) + 2 CH3COO– (aq)

Ca2+(aq) + SO42–(aq) CaSO4(s)

total ionic equation

net ionic equation

Write the net ionic equation for the reaction oflead(II) nitrate and copper(II) chloride.

Pb2+(aq) + 2 NO3–(aq) + Cu2+(aq) + 2 Cl–(aq)

PbCl2(s) + Cu2+(aq) + 2 NO3–(aq)

Pb2+(aq) + 2 Cl–(aq) PbCl2(s)

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Electron Affinity and Electronegativity

Increases• from the bottom to the top• from the left to the right