Chapter 8 Acids, bases, Salts, Lewis

diagrams and Organic compounds

Science 10

Almost all the compounds we have studied so far are inorganic compounds…such asH20, CO2, Fe2O3, NaCl, Al2(SO4)3, K3N…etc

Inorganic compounds are either Ionic Covalent (molecular)Acids, bases, salts

Classification of compounds

Acids: they release H (hydrogen ions) in solutionsEx:

Note: they all start with H

Arrhenius definitions

Bases: they release OH (hydroxide ions) in solutionsEx:

Note: they all end with OH

Arrhenius definitions

Salts: release positive and negative ions other than H or OH

Ex:

Arrhenius definitions

Really easyFollow the previous rules we learnt

Ex:HCl

HNO3

H2SO3

Naming?

NaOH

Ca(OH)2

Al(OH)3

Bases

They don’t start with H or end with OH

KCl

NaNO3

Na2SO4

Salts

Indicators are used to test for acids and bases …Look at page 203 (table 2)

Pay attention to the changes of colours that happenMethyl orange is _________ in acid is _________ in base

Check the chart in data booklet

Chemical indicators

Acids start with H, and produce H ions in solutions. Therefore, acids have more H than they do OH

Bases ends with OH, and produce Oh ions in solutions. Therefore, bases have more Oh ions than they do H ions

When H = OH neutral solutions knowns as salts

Explaining acids, bases & salts

Look at Fig 6 page 205 VERY IMPORTANT!

The pH scale The pH scale allows chemists to quickly determine the acidity of solutions.

Look at Fig 6 page 205

VERY IMPORTANT!

The pH scale allows chemists to quickly determine the acidity of solutions.Ex: apple have a pH=3 means they are _______ soap has a pH= 10 means it is _________

The pH scale

Lewis Diagrams …

Gilbert Newton Lewis

I’m so tired of writing all those useless inner

electrons, in the

Bohring models!

Gilbert Newton Lewis

Invented “Electron-dot” or

“Lewis” Structures

Valence Electrons – electrons in the outermost occupied energy level.

Valence electrons can be represented by “dots” drawn around the atom.

Remember the rules…

EXAMPLES

F

B

O

Ar

Octet Rule: All atoms attempt to achieve a complete valence shell similar to their nearest noble gas.

Lewis structure for ionic compounds

LEWIS STRUCTURE FOR MOLECULES (MOLECULAR/COVALENT COMPOUNDS)

MORE EXAMPLES

ORGANIC COMPOUNDS

They have carbon ,C atoms, as their basis and H … and sometimes they have O, N and other non-metals.

Carbon, very special, group 14, so 4 valence electrons.

It can form several bonds with other atoms as well as with itself. Carbon contains chains of various lengths and these chains can have all types of branches

ORGANIC COMPOUNDS

HOMEWORK

Page 2096,8,13,15,16

Page 2142,4,6

Page 2209