+ All Categories
Home > Documents > Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of...

Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of...

Date post: 21-Sep-2020
Category:
Upload: others
View: 5 times
Download: 0 times
Share this document with a friend
26
Intramolecular force vs Intermolecular force Intramolecular forces are stronger than Intermolecular forces. 1 Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding - Between metallic and nonmetallic elements of different electronegativity. 3. Metallic bonding - Between metallic elements. Types of Intramolecular Forces(Chemical Bonding) 2 Fill in the blank substance Type of bond substance Type of bond S 8 SiC HNO 3 Cr 2 O 3 CuCl Ti CoSO 4 SiH 4 Na KI CaHPO 4 Au CH 2 O K 4 [Fe(CN) 6 ] 3 Covalent bonding - e»¹¾a ¹¸a·ÕèÁÕ¡ÒÃ㪠oieÅç¡μÃo¹ÃÇÁ¡a ¹e»¹¤Ù æ Examples; O 2 , CO 2 , C 2 H 6 , H 2 O, SiC , F 2 H 2 - bonding The bond occure from the together attraction of 2 nuclei for the same electrons. H + H H 2 4
Transcript
Page 1: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Intramolecular force vs Intermolecular force

Intramolecular forces are stronger than Intermolecular forces.

1

Chemical bond1. Covalent bonding

- Between nonmetallic elements of similar

electronegativity.

2. Ionic bonding- Between metallic and nonmetallic elements of

different electronegativity.

3. Metallic bonding- Between metallic elements.

Types of Intramolecular Forces(Chemical Bonding)

2

Fill in the blanksubstance Type of bond substance Type of bond

S8 SiCHNO3 Cr2O3

CuCl TiCoSO4 SiH4

Na KICaHPO4 AuCH2O K4[Fe(CN)6]

3

Covalent bonding- e» �¹¾ a¹¸a·ÕèÁÕ¡ÒÃ㪠�oieÅ硵Ão¹Ã �ÇÁ¡ a¹e» �¹¤Ù�æ

Examples; O2, CO2, C2H6, H2O, SiC , F2

H2 - bonding

The bond occure from the together attraction of 2 nuclei for the same electrons.

H + H H2

4

Page 2: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Lewis dot symbol of elements

5

Types of Covalent Bonding1. single bond ¡ÒÃÊà �Ò§¾ a¹¸ao´Âãª�oieÅ硵Ão¹Ã �ÇÁ¡ a¹ 1 ¤Ù�.

Give ( - ) for single bond such as Cl2 , NH3 etc.

6

bond pair electrons vs lone pair electrons

7

2. Double bond ¡ÒÃÊà �Ò§¾ a¹¸ao´Âãª�oieÅ硵Ão¹Ã �ÇÁ¡ a¹ 2 ¤Ù�. Give ( = ) for double bond such as O2 , CO2 , C2H4

8

Page 3: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

3. Triple bond ¡ÒÃÊà �Ò§¾ a¹¸ao´Âãª�oieÅ硵Ão¹Ã�ÇÁ¡ a¹ 2 ¤Ù�. . Give( ≡ ) for triple bond such as N2 , HCN , C2H2

9

Coordinate covalent bond e»�¹¾ a¹¸a·ÕèoaµoÁã´oaµoÁ˹è§e»�¹½ �ÒÂãË �oieÅ硵Ão¹¤Ù�o´´e ÕèÂÇæ¡ �

oaµoÁo è¹æ following �Octet Rule� such as NH3 and H+ , SO2 , SO3

10

¨§e¢Õ¹¾ a¹¸ao¤ooà � ie¹µo¤eÇeŹµ � ¢o§oÁeÅ¡ uŵ �o仹Õé SO3 O3

HClO4 HNO3

HClO3 BF3 + NH3

11

Non-octet Molecules- Less octet molecules such as BeCl2 , BCl3

- More octet covalent molecules such as PCl5 , SF6

12

Page 4: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Nomenclature of Covalent Compound1. Covalent Elements ; eÃÕ¡µÒÁª èo¸Òµ u ¶ �ÒÁÕʶҹaæ¡ �ÊãË�Ãaºu �ÇÂ

O2

Cl2P2

Br2S8

2. Covalent compounds ; eÃÕ¡o´Âãª� prefixes ºo¡¨íҹǹoaµoÁ ¹íÒ˹ �Òª èo¸Òµ uæÅaŧ· �ÒÂeÊÕ§ �Ç -ide.prefixes mono = 1 , di = 2 , tri = 3 , tetra = 4 , penta = 5

hexa = 6 , hepta = 7 , octa = 8 , nona = 9

13

ExampleCO2 named ���������.���������..���������...

BF3 named ���������.���������..���������...

Cl2O named ���������.���������..���������...

Si2Cl8 named ���������.���������..���������...

Tetraphosphorous decoxide formula : Dichlorine heptabromide formula : Dicarbon Hexahidride formula : Trihydrogen monoarsenide formula :

14

Writing the formula for covalent compounds1. Find the number of bonds that element want to form ;

Group 1 : H : form : 1 bondsGroup 2 : Be Mg : form : 2 bonds

Group 3 : B : form : 3 bonds Group 4 : C Si : form : 4 bonds

Group 5 : N : form : 3 bonds Group 6 : O S : form : 2 bonds Group 7 : F Cl Br I : form : 1 bond

15

Ex formula(following rules)B and FSi and ClN and HC and SSi and ClCl and OSn and HSe and BrH and Te

16

Page 5: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Bond length and Bond Energy

17

Bond length (pm)

18

Bond Energies (kJ/mol)

19

summary

Comparison of Bond length between same elements

Comparison of Bond energy between same elements

20

Page 6: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Calculating ΔH using bond energies.Form bond : Exothermic reaction : H = (-)

Break bond : Endothermic reaction : H = (+)

H is Heat

Form bond

e.g. 2Cl (g) Cl2 (g) ; H = 242 kJ/molBreak bond

e.g. Cl2 (g) 2Cl (g) ; H = -242 kJ/mol

21

Example : Calculate the energy for breaking CO2 1 mol from molecule to atoms and this process is endothermic or exothermic reaction.

Example : Calculate the energy for breaking CCl4 2 mol from molecule to atoms and this process is endothermic or exothermic reaction.

22

Example : Calculate the energy of the reaction for the burning of methane in oxygen. The balanced equation is given below. Use the following list of bond energies

CH4(g) + 2O2(g) CO2(g) + 2H2O (g)

23

Ex Chlorine gas react with methane gas following below equation

CH4(g) + 2Cl2(g) CH2Cl2(g) + 2HCl (g) this process is endothermic or exothermic reaction and how many energies change.

24

Page 7: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Resonancee»�¹»ÃÒ¡¯¡Òó �·ÕèoieÅ硵Ão¹e¤Åèo¹·Õèä»ã¹oÁeÅ¡ uÅËÃoäooo¹·ÕèÁÕ¾ a¹¸a¤Ù�

¨ §ÊÒÁÒöe¢Õ¹Êٵ÷Õè¶Ù¡µ�o§ä �ËÅÒÂ滺.

25

Draw Resonance structure of O3, SO3, PO43-, -, SO3

2-, SO42-

26

- เปนทฤษฎทใชอธบายการเกดพนธะในโมเลกลของสารประกอบโคเวเลนต1. sp3 -hybrid orbital

ไดจากการรวมกนของ s-orbital 1 orbital และ p-orbital 3 orbitalExample CH4

พจารณาการจดอเลกตรอนของอะตอมกลาง 6C :1s22s2 2p2

• Four atomic orbitals (2s + 3 × 2p) mix to form four hybrid orbitals (4 × sp3)

ทฤษฏไฮบรดออรบทล

27

sp3 Hybrid Orbitals

28

Page 8: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

พนธะทง 4 ใน CH4 เกดจาก 1s -orbital ของ H 4 อะตอม ซอนเหลอม(overlap) กบ 2sp3-orbital ของ C 1 อะตอม

sp3

C

29

2. sp2 -hybrid orbitalไดจากการรวมกนของ s-orbital 1 orbital และ p-orbital 2 orbital

Example BF3

พจารณาการจดอเลกตรอนของอะตอมกลาง 5B :1s22s2 2p1

พจารณาการจดอเลกตรอนของอะตอมขางเคยง 9F :1s22s2 2p5

Three atomic orbitals (2s + 2 × 2p) mix to form three hybrid orbitals (3 × sp2)

30

sp2 Hybrid Orbitals

31

พนธะทง 3 ใน BF3 เกดจาก 2p -orbital ของ F 3 อะตอม ซอนเหลอม(overlap) กบ 2sp2-orbital ของ B 1 อะตอม

2sp2

B B

32

Page 9: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Ethylene H

H

H

HC = C

1. Each C – H bond is a σ bond formed from the overlap of a C sp2 orbital with the H 1s orbital.

2. One of the C – C bonds is a σ bond formed from the overlap of C sp2 orbitals3. The second C – C bond is a π bond formed from the overlap of the unhybridized

C 2p orbitals.

sp2 -hybrid orbital

33

3. sp -hybrid orbitalไดจากการรวมกนของ s-orbital 1 orbital และ p-orbital 1 orbital

Example BeCl2

พจารณาการจดอเลกตรอนของอะตอมกลาง 4Be :1s22s2

พจารณาการจดอเลกตรอนของอะตอมขางเคยง 17Cl :1s22s22p63s22p5

Two atomic orbitals (2s + 2p) mix to form two hybrid orbitals (2 × sp)

2

34

sp Hybrid Orbitals

35

พนธะทง 2 ใน BeCl2 เกดจาก 3p -orbital ของ Cl 2 อะตอม ซอนเหลอม(overlap) กบ 2sp-orbital ของ Be 1 อะตอม

2spBe

36

Page 10: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Acetylene H - C ≡ C - H

1. Each C – H bond is a σ bond formed from the overlap of a C sp orbital with the H 1s orbital.

2. One of the C – C bonds is a σ bond formed from the overlap of C sp orbitals.3. The other two bonds are π bonds formed from the overlap of the C 2p orbitals.

sp -hybrid orbital

37

Molecular shapes(Molecular Geometry)

Valence-Shell Electron-Pair Repulsion (VSEPR) theory e»�¹·ÄɮշÕèãª�㹡Ò÷íÒ¹ÒÂÃٻà �Ò§oÁeÅ¡ uÅ o´ÂoÁeÅ¡ uÅ·ÕèeʶÕÂèaµ�o§¨ a µaÇãË�oieÅ硵Ão¹æµ�Åa¤Ù�oÂÙ�Ë�Ò§¨Ò¡¡ a¹ÁÒ¡·ÕèÊu´ e¾ èoÅ´æç¼Åa¡ã¹oÁeÅ¡ uŹ aé¹æ

• The "AXE method" of electron counting is commonly used when applying the VSEPR theory.

AXmEn

38

39

Method to determine a molecular shapes

Covalent compound CF4Molecular shape

# valent ē of center atom

# ē of outside atom to form bond

# ē from charge

total e

# bond pair ē or # bond

# lone pair ēfomular

Hybrid Orbitals

Angle between atom 40

Page 11: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Method to determine a molecular shapes

Covalent compound CO32- Molecular shape

# valent ē of center atom

# ē of outside atom to form bond

# ē from charge

total e

# bond pair ē or # bond

# lone pair ē

fomular

Hybrid Orbitals

Angle between atom

41

Method to determine a molecular shapes

Covalent compound NH4+ Molecular shape

# valent ē of center atom

# ē of outside atom to form bond

# ē from charge

total e

# bond pair ē or # bond

# lone pair ē

fomular

Hybrid Orbitals

Angle between atom

42

Polarity in Polyatomic MoleculesPolarity

Bond Molecule

- Polar bond - Polar molecule- Non-polar bond - Non-polar molecule

Determine polarity of bond by using EN

43

Non-polar bond- EN = 0 e.g. H2 , N2 , Cl2 - If the molecule has non-polar bond so this molecule

is also Non-polar molecule.

Polar bond - EN > 0 e.g. HCl, CO2 , N2O

- If the molecule has polar bond this molecule can be Non-polar molecule or Polar molecule.

44

Page 12: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Polar bond but Non-polar molecule

e.g. CO2 , BF3

Polar bond and Polar molecule e.g C2H2Cl2 , H2O

ᵟ-ᵟ+ᵟ- B

F

F F

45

� Polarity can use to predict a solubility of molecule in a solvent �Example Polar molecule can soluble in polar molecule

e.g. NH3 , C2H5OH , H2O are polar molecule

So NH3 and C2H5OH can soluble in water(H2O)

Non-polar molecule cannot soluble in polar molecule but can soluble in non-polar molecule.

Oil is non-polar molecule So Oil cannot soluble in water but oil can soluble in non-polar molecule such as Hexane(C6H12)

46

1. Van der Waals force1) Dipole-dipole interaction e»�¹æç´§ Ù´ÃaËÇ �Ò§ polar

moleculese.g. I-Cl----- I-Cl2) Dipole-induced dipole interaction e»�¹æç´§ Ù´ÃaËÇ �Ò§

polar molecule æÅa non-polar moleculee.g. H-Cl----- Cl-Cl3) Dispersion force or London force e»�¹æç´§ Ù´ÃaËÇ �Ò§

non-polar molecules e.g. F2-----F2

Intermolecular force

47

Hydrogen Bondinge»�¹¾ a¹¸a·Õèe¡ i´¨Ò¡oaµoÁ¢o§äÎo´Ãe¨¹ ¶Ù¡oaµoÁ·ÕèÁÕ¤ �Ò EN

ÁÒ¡ eª �¹ N O F ¢o§oÁeÅ¡ uÅo è¹ e.g. Hydrogen bonding in HF molecule

H — F ……. H — F

48

H O.. ..

HH O.. ..

H.. ..H OH

..

H O..H

Page 13: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Effect of Hydrogen bond

49

Network Structure - The structures of giant covalent substances like

diamond, graphite and silicon dioxide

1. Diamond

The physical properties of diamond- has a very high melting point (almost 4000oC). - is very hard. - doesn't conduct electricity. All the electrons are

held tightly between the atoms, and aren't free to move.

3D of Diamond

50

2. Graphite

The physical properties of graphite

- has a high melting point.

- has a soft, slippery feel, and is used in pencils and as a dry lubricant for things like locks.- has a lower density than diamond. - conducts electricity. The delocalised electrons are free to move throughout the sheets.

2D of Graphite

51

Silicon dioxide, SiO2

Crystalline silicon has the same structure as diamond. each silicon atom is bridged to its neighbours by an oxygen atom.

The physical properties of silicon dioxide- has a high melting point

- is hard- doesn't conduct electricity

3D of SiO2

52

Page 14: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Ionic Bondinge» �¹¾ a¹¸a·Õèe¡ i ¨Ò¡oaµoÁ 2 oaµoÁ ÁÕ¡Òö �ÒÂe·oieÅ硵Ão¹

ãË �æ¡ �¡ a¹- Metals lose electrons and form positive

charge(cation)- Nonmetals gain electrons and form negative

charge(anions)note ;

The Octet Rule: The �goal� of most atoms is to have an 8 electrons in their valence energy level.

Li+ N3- O2- F-

Na+ Mg2+ Al3+ P3- S2- Cl-

K+ Ca2+ Transition metal can form morethan one type of positive ion

Cr2+ Cr3+ Mn2+ Mn3+

Mn4+ Fe2+ Fe3+ Co2+ Co3+ Cu+ Cu2+

Ga3+ Ge4+ As3- Se2-

Br-

Rb+ Sr2+ In3+ Sn2+

Sn4+

Sb3- Te2-

I-

Cs+ Ba2+ Tl3+ Pb2+

Pb4+

Bi3+

H+

H-

Cation and anion

54องคาร เทพรตนนนท

Examples ; NaCl Ionic BondingBetween Ca and Cl to form CaCl2

Page 15: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Crystal structure of Ionic compound

Na+ : Cl-

:

:

Na+ has ���� nearest Cl- neighbors

Cl- has ���� nearest Na+ neighbors

57องคาร เทพรตนนนท

Ca2+

F-

Ca2+ has ���� nearest F- neighbors

F - has ���� nearest Ca2+ neighbors

Ca2+ : F-

:

:58องคาร เทพรตนนนท

Crystal structure of Ionic compound

Crystal structure of Ionic compound

59องคาร เทพรตนนนท

Cs+ has ���� nearest Cl- neighbors

Cl - has ���� nearest Cs+ neighbors

Cs+ : Cl-

:

:

o¤Ã§Êà �Ò§¢o§ÊÒûÃa¡oºäooo¹ i¡

60องคาร เทพรตนนนท

Page 16: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Writing Ionic Formula1. Always write cation and charge of this ion first.2. The net charge on an ionic compound is zero (sum of the positive charges equals the sum of the negative charges). 3. The formula of an ionic compound represents the simplest whole number ratio of ions present.

Na and Cl Na+ and Cl-

Mg and F Mg2+ and F-

Ba and OCH3COO- and CaNH4

+ and PO43-

61

Write Ionic Formula

cationanion

Na Ca Al NH4

F

O

N

CN

CO3

PO462องคาร เทพรตนนนท

Naming Ionic Compounds¡ÒÃeÃÕ¡ª èo¨aµ �o§eÃÕ¡ª èoäooo¹ºÇ¡¡ �o¹äooo¹ÅºeÊÁo Naming Positive Ions(Cation)

1. äooo¹ºÇ¡·ÕèÁÕ»Ãa u¤ �Òe ÕÂÇ , The name is that of the metal plus the word �ion.� For example,

Na+ is the Mg2+ is the Al3+ is the NH4

+ is the

63องคาร เทพรตนนนท

2. äooo¹ºÇ¡·ÕèÁÕ»Ãa uËÅÒ¤ �Ò , The most common practice is to indicate the charge of the ion by a Roman numeral in parentheses immediately following the ion�s name. For example,

Co2+ is the Co3+ is the Sn2+ is the Sn4+ is the

Page 17: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Naming Negative Ions(Anion)1. äooo¹Åº¢o§¸Òµ u , Named by adding the suffix -

ide to the root of the element name. For example,Cl- is theO2- is the

2. ¡Åu�Áäooo¹Åº , Most of these names must simply be learned. For example,

NO2- is the

NO3- is the

SO32- is the

CN- is the

ExampleNaCl :MgO :FeCl2 : CuO :MnO2 : (NH4)3PO4 : Li2NO3 :Cr2(SO4)3 :Mn(OH)4 :

66องคาร เทพรตนนนท

Naming Ionic Compound

1. NaBr2. K3N3. NH4Cl 4. Be(HCO3)25. Al(CN)36. Cu3P7. Pb3N2

8. Mn2(SO3)3

67องคาร เทพรตนนนท

Cycle of Ionic compounds

องคาร เทพรตนนนท 68

Page 18: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Born-Harber cycleThe Born�Haber cycle involves the formation of an ionic

compound from the reaction of a metal with a non-metal. There are five steps.

1. Heat of Sublimation ; S

2. Dissociation Energy ; D or bond enthalpy

3. Ionization energy ; IE

4. Electron Affinity ; EA

5. Lattice energy ; ΔHlatt

H0f = S + D + IE + EA + ΔHlatt

69องคาร เทพรตนนนท

The enthalpy of formation of Sodium chloride

70องคาร เทพรตนนนท

Step 1

Step 2

Step 3

Step 4

Step 5Net Reaction :

The Heat(enthalpy) of formation of Sodium chloride

Heat of Sublimation Dissociation Energy Ionization energy Electron Affinity Lattice energy

71องคาร เทพรตนนนท

Draw a diagram and calculate the heat of formation of LiF

Give1. Heat of Sublimation of Li = 161 kJ/mol2. Dissociation Energy of F2 = 159 kJ/mol3. First Ionization energy of Li = 520 kJ/mol4. Electron Affinity of F= -328 kJ/mol5. Lattice energy of LiF = -1,047 kJ/mol

72องคาร เทพรตนนนท

Page 19: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

The Heat(enthalpy) of formation of Lithium chloride

step 1

step 2

step 3

step 4

step 5

Net reaction

73องคาร เทพรตนนนท

Born-Haber cycle of LiF

74องคาร เทพรตนนนท

Draw a diagram and calculate the heat of formation of MgCl2

Give1. Heat of Sublimation of Mg = 148 kJ/mol2. Dissociation Energy of Cl2 = 234 kJ/mol3. First Ionization energy of Mg = 738 kJ/mol4. Second Ionization energy of Mg = 1,451 kJ/mol5. Electron Affinity of Cl = -349 kJ/mol6. Lattice energy of MgCl2= -2,524 kJ/mol

75องคาร เทพรตนนนท

The Heat(enthalpy) of formation of Magnesium chloride

Step 1

Step 2

Step 3(IE1+IE2)Step 4

Step 5

Net reaction :

76องคาร เทพรตนนนท

Page 20: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Born-Haber cycle of MgCl2

77องคาร เทพรตนนนท

Physical Properties of Ionic Compounds

Hard , crystalline solids but crack High melting point and boiling point Solid do not conduct electricity , when molten or dissolved in water , they can conduct electricity. Many ionic compound are soluble in water.

78องคาร เทพรตนนนท

Electrical Conductance of Ionic Compounds

79องคาร เทพรตนนนท

Physical Properties of Ionic Compounds

Compound Appearance Melting point

(C)

Boiling point

(C)

Soluble in water at 20C(g/water 100 g)

NaClLiF

CaCl2Al2O3

Fe2O3

White solidWhite solidWhite solidWhite solidRed Brown

solid

80184678220721565

1413171716002980

-

36.00.1374.5

Not solubleNot soluble

80องคาร เทพรตนนนท

Page 21: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Ionic compounds dissolve in waterSome ionic compounds (salts) dissolve in water, the

salt's positive ions (e.g. Na+) attract the partially-negative oxygens in H2O. Likewise, the salt's negative ions (e.g. Cl−) attract the partially-positive hydrogens in H2O.

Dissolve in water of Ionic compounds relate with 2 steps

1. Lattice Energy2. Hydration Energy

องคาร เทพรตนนนท 81

Ionic compounds dissolve in water

82องคาร เทพรตนนนท

Lattice energy is the energy required to break the ions in their lattice arrangement into the ions in the gas phase , For example

NaCl(s) ---> Na+(g) + Cl-(g) Hydration energy is the energy released when the ion

dissolves in water forming an infinite dilute solution in the process, For example

Na+(g) + Cl-(g) ---> Na+(ag) + Cl-(ag) Heat of Solution is the energy required or released

when 1 mole ionic compound dissolves in solvent(water). Heat of Solution = Lattice energy - Hydration energy

Hsolution = Hlattice + Hhydration

83องคาร เทพรตนนนท

Example Dissolving NaCl in water

Lattice energy

NaCl(s) Na+(g) + Cl-(g) H = 776 kJ/mol

Hydration energy

Na+(g) + Cl-(g) Na+(aq) + Cl-(aq) H = - 771 kJ/mol

Heat of solution

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

Hsolution = 776 - 771 = 5 kJ/mol

84องคาร เทพรตนนนท

H2O

H2O

Page 22: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Diagram of dissolving NaCl in water

85องคาร เทพรตนนนท

If ΔHlatt > ΔHhyd so, ΔHsoln is + (Endothermic process)If ΔHlatt < ΔHhyd so, ΔHsoln is - (Exothermic process)

86องคาร เทพรตนนนท

Ionic compound

Mass(g)

Temperature of water (0C)

Temperature of solution (0C)

Process

CuSO4 1 31.0 35.0

NH4Cl 1 31.0 29.0

NaCl 1 31.0 30.5

KCN 1 31.0 32.5

Ionic compounds dissolve in water

Dissolving KCl in water1. Hlatt = +690 kJ/mol

2. Hhyd = -686 kJ/mol

Write the equation when KCl dissolved in water and calculate Hsoln

Lattic equation (ÊÁ¡ÒÃæÊ´§¾Å a§§Ò¹æŵ· i«)

:

Hydration equation (ÊÁ¡ÒÃæÊ´§¾Å a§§Ò¹äÎe´Ãª a¹)

:

Solution (ÊÁ¡ÒáÒÃÅaÅÒÂ)

:

87องคาร เทพรตนนนท

Diagram of dissolving KCl in water

88องคาร เทพรตนนนท

Page 23: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Write the equation to show the dissolving Ionic compound in water

1. MgBr2

Lattic equation :

Hydration equation :

Solution equation :

2. Na2O

Lattic equation :

Hydration equation :

Solution equation :

องคาร เทพรตนนนท 89

3. NH4F

Lattic equation :

Hydration equation :

Solution equation :

4. K2CO3

Lattic equation :

Hydration equation :

Solution equation :

องคาร เทพรตนนนท 90

Solubility of Ionic compound

91องคาร เทพรตนนนท

- Less than 0.1 g of the substance will dissolve in 100 g of water, the substance is considered insoluble.

- Between 0.1 - 1 g of a substance will dissolve in 100 g of water, the substance is considered moderately soluble.

- More than 1 g of a substance will dissolve in 100 g of water, the substance is considered soluble.

Solubility rules

Page 24: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

Writing Net Ionic Equationssteps for write net ionic reactions :

1. balance the chemical equation. 2. write out the dissolved species as they exist in

solution. Precipitates, liquids and gases are not written as ions. This is called a total ionic equation.

3. remove common aqueous ions, ( ions that are in both the reactant and product) . The resulting equation is called the net ionic equation.

องคาร เทพรตนนนท 94

eª�¹ » i¡ ià iÂÒÃaËÇ �Ò§ÊÒÃÅaÅÒ Barium chloride ¡a[ Sodium carbonate

1. Write the chemical equations and balance BaCl2(aq) + Na2CO3(aq) --> BaCO3(s) + 2NaCl(aq)

2. Write the species as they exist in solution. Leave solids, liquids and gases unchanged.

Ba2+(aq) + 2Cl-(aq) + 2Na+(aq) + CO32-(aq)

---> BaCO3(s) + 2Na+(aq) + 2Cl-(aq) 3. Remove common aqueous ions. (Net Ionic Equations )

Ba2+(aq) + CO32-(aq) ---> BaCO3(s)

องคาร เทพรตนนนท 95

Writing Net Ionic Equations

1. KCl and AgNO3

Chemical Equation :

Ionic Equation :

Net Ionic Equation :

2. KBr and Mg(NO3)2

Chemical Equation :

Ionic Equation :

Net Ionic Equation :

องคาร เทพรตนนนท 96

Page 25: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

3. Na2O and AlCl3

Chemical Equation :

Ionic Equation :

Net Ionic Equation :

4. MgBr2 and Pb(ClO3)2

Chemical Equation :

Ionic Equation :

Net Ionic Equation :

องคาร เทพรตนนนท 97

¾ a¹¸aoÅËa ¤o ¾ a¹¸a·Õèe¡ i´¨Ò¡æç´§ Ù´ÃaËÇ �Ò§äooo¹ºÇ¡·ÕèeÃÕ§ª i´¡ a¹¡ aºoieÅ硵Ão¹·ÕèoÂÙ�o´ÂÃoº

溺¨íÒÅo§·aeÅoieÅ硵Ão¹ (electron sea model)

·íÒäÁoieÅ硵Ão¹¢o§oÅËa¶§e¤Å èo¹·Õèä´ �µÅo´eÇÅÒ?

• oÅËaÁÕ¤ �Ò¾Åa§§Ò¹äoooä¹e«« a¹·ÕèµèíÒ a§¹a鹨§Â´oieÅ硵Ão¹ ǧ¹o¡Êu´äÇ �oÂ�Ò§ËÅÇÁæ ·íÒãË �oieÅ硵Ão¹eËÅ�Ò¹Õée¤Åèo¹·Õèä»ÁÒÃoºæ oÅËaµÅo´eÇÅÒ

• oieÅ硵Ão¹eËÅ�Ò¹Õé·íÒ˹�Ò·Õè¤Å�Ò¡ÒÇ·Õèª �Ç ´äooo¹ºÇ¡ãË �oÂÙ�ã¹µíÒæ˹�§·Õ褧·Õè äÇ � �Ç¡ a¹oÂ�Ò§æ¢ç§æç

• ¤ÇÒÁæ¢ç§æç¢o§¾ a¹¸aoÅËa¢ é¹oÂÙ�¡ aº¨íҹǹoieÅ硵Ão¹ oiÊÃaæÅa¢¹Ò´¢o§äooo¹ºÇ¡

¾ a¹¸aoÅËa¡ aºÊÁº aµ iºÒ§»Ãa¡Òâo§oÅËa1. ¹íÒä¿¿ �ÒæÅa¤ÇÒÁà �o¹ä´ � Õ

¡Ò÷ÕèoieÅ硵Ão¹ÊÒÁÒöe¤Åèo¹·Õèä»ÁÒã¹oÅËaä � ·íÒãË �oÅËaÁÕ¤ u³ÊÁº aµ ie»�¹µ aǹíÒ¤ÇÒÁà �o¹æÅaä¿¿ �Ò·Õè Õ 2. ÊÒÁÒöµÕe» �¹æ¼ �¹Ëà o´§e» �¹eÊ �¹ä´ �

Page 26: Chemical bond - WordPress.com...Chemical bond 1. Covalent bonding - Between nonmetallic elements of similar electronegativity. 2. Ionic bonding-Between metallic and nonmetallic elements

3. ÁÕ¼ iÇe» �¹Á a¹ÇÒǼiÇ˹�Ò¢o§oÅËae»�¹Áa¹ÇÒÇ e¹èo§¨Ò¡oieÅ硵Ão¹oÂÙ�äÁ�»Ãa íÒ·Õè

æÅae¤Åèo¹·Õèä �oÂ�Ò§oiÊÃa¨aÊÒÁÒö Ù´¡Å¹ æÅa¡Ãa¨ÒÂæʧä � ¨§·íÒãË �oÅËaÊÒÁÒöÊa·�o¹æʧä �4. ÁÕ¨ u´e´ o´-¨ u´ËÅoÁeËÅÇÊÙ§

e¹èo§¨Ò¡¾ a¹¸aoÅËae»�¹¾ a¹¸a·Õèæ¢ç§æç e¡ i´¨Ò¡æç ´e˹ÕèÂÇÃaËÇ �Ò§eÇeŹ«�oieÅ硵Ão¹oiÊÃa·aé§ËÁ´¡ aºäooo¹ºÇ¡

5. e¤ÒaÁÕeÊÕ§´ a§¡ a§ÇÒ¹

e¹èo§¨Ò¡äooo¹ºÇ¡oÂÙ�ã¡Å�ª i´¡ a¹ÁÒ¡·íÒãË �¡ÒÃÊ aè¹Êae·o¹¢o§o¹uÀҤ㹡 �o¹oÅËa Ê�§æÃ§Ê aè¹Êae·o¹ä»¶ §¡ a¹oÂ�Ò§ÃÇ´eÃçÇ ¨§e¡ i´eÊÕ§oo¡ÁÒ �ǤÇÒÁ¶Õè¤ �o¹¢�Ò§ÊÙ§e»�¹eÊÕ§¡ a§ÇÒ¹

ÊÁº aµ i·Õè¡Å �ÒÇÁÒ¹ aé¹e»�¹e¾Õ§Ša¡É³a· aèÇ仢o§oÅËa «è§oÅËaæµ �Åaµ aÇoÒ¨ÁÕÅa¡É³aºÒ§»Ãa¡Òþ ieÈÉ eª �¹

- ã¹ÀÒÇa»¡µ ioÅËa · aèÇä»e»�¹¢o§æ¢ç§Â¡eÇ�¹ Hg « è§e»�¹¢o§eËÅÇ - µa¡aèÇe»�¹oÅËa·Õè¹íÒä¿¿�Òä´�äÁ�´Õ


Recommended