Main Menu

Taking notes: the two-thirds-one-third method Divide each page with a vertical line one-

third of the way across it.

Write your class notes in the right-hand column Preferably in your own words Preferably with other bits to cover

textbook/what I say, not just what is on the PowerPoint

Review your notes in the left-hand column (at night for homework):

Draw diagrams that might help you remember things

Use colours to highlight key ideas Write in any connections you have spotted with

other topics and subjects

Class notes here

Review notes here

Main Menu

Writing your mind-map Use the outline mind-map provided on slide 5 Make it BIG

Main Menu

Overview Copy this onto a double-page spread. You should add to it as a

regular review throughout the unit.

Chapter: 10 Organic ChemistryTitle: Lesson 1 Homologous SeriesLearning Objectives:

– Reflect on previous knowledge of organic chemistry

– Understand the term ‘homologous series’

– Conduct the fractional distillation of crude oil

– Understand and use the variety of different types of formula used in organic chemistry

Main Menu

Reflecting on Organic Chemistry

Brainstorm everything you already know about organic chemistry

You have 1 minute

Organic Chemistry - IGCSE

Main Menu

Organic Chemistry Organic chemistry is the chemistry of compounds that contain

Carbon and, in nearly all cases, also contains Hydrogen in a covalently bonded structure.

Organic chemistry includes the study of: All biological molecules- from simple sugars to complex nucleic acids All fossil fuels – including oil, coal, and natural gas Nearly all synthetic materials – such as nylon, Lycra, and Gore-Tex Many domestic and industrial products – such as paints, detergents,

and refrigerants

Carbon has the ability to form four strong covalent bonds Carbon can link itself in chains and rings – known as catenation

Main Menu

Homologous Series A homologous series is

a family of compounds that differs only by the length of its hydrocarbon chain

Members share: General formula Chemical properties

Members show a graduation in: Physical properties

Three such series are the: Alkanes Alkenes Alcohols

Successive members of a homologous series differ by a -CH2 group

Main Menu

Homologous Series and Boiling Points What do you think will be the trend in melting/boiling points as

you go down a homologous series?

Why?Increased instantaneous induced dipoles causing stronger London (dispersion) forces between the molecules as molecular size increases…NOTE: Increase is not linear, but steeper near the beginning as the influence of increased chain length is proportionally greater for small molecules…

Other predictable trends with increasing carbon length are density and viscosity…

Main Menu

Homologous series and chemical properties Same chemical properties are due to the same functional

group

For example: Alcohols have the –OH group, which can be oxidized to form

organic acids Carboxylic acids have the -COOH group, which is responsible

for the acidic properties

Main Menu

Fractional Distillation of Crude Oil (25 mins)

Crude oil is the main feedstock for producing organic compounds

Complete the fractional distillation of crude oil experiment here.

Fully explain all your observations

Main Menu

Formulas

Draw the compound with the formula C4H8O

How many can you get in 10 minutes?

Main Menu

Ask Ms Easton for the answers after 10 minutes…

Main Menu

What did you get? Clearly a

molecular formula is not enough!

Main Menu

Types of Formula Empirical Formula C4H8O C4H8O

Molecular Formula C4H8O C4H8O

Full Structural Formula Aka displayed formula

Condensed Structural Formula Note the ‘=‘ used for the C=C double bond

Stereochemical Formula

Skeletal formula Not required but v. useful Used in data booklet for complicated structures

CH2=CHCH2CH2OH CH2=C(CH3)CH2OH

Simplest whole number ratio

Actual number of atoms of each element present

Shows every bond and atom

Groups atoms together and omits bonds that can be assumed

Shows 3D positions

Do not use in exam answers!

15 of 30 © Boardworks Ltd 2009

Displayed and structural formula activity

16 of 30 © Boardworks Ltd 2009

Types of formulae

Main Menu

Another summary… NOTE: If we do not need to show the exact detail, we can abbreviate to R…

Main Menu

Nomenclature for organic compounds: the IUPAC system Need a specific set of rules for naming organic compounds. Give information about the functional groups and size of

molecules.

Summary of rules: Rule 1 – Identify the longest straight chain of carbon atoms Rule 2 - Identify the functional group Rule 3 – Identify the side chains or substituent group

Main Menu

Rule 1: Identify the longest straight chain of carbon atoms The longest chain of carbon atoms gives the stem of the name as follows:

Note: ‘Straight chain’ refers to continuous or unbranched chains of carbon atoms – not angles of 180o. E.g. all the structures below are for Pentane, C5H12, even though they look different.

Main Menu

Rule 2: Identify the functional group The functional group usually determines the specific ending

or suffix to the name.NOTE the distinction between class, which refers to type of compound, and functional group, which refers to the site of reactivity in the molecule…Try to remember these functional groups… I will test you on these next week…!

21 of 30 © Boardworks Ltd 2009

Functional groups

22 of 30 © Boardworks Ltd 2009

Homologous series

Main Menu

Position of functional group Shown by a number between dashes inserted before the functional

group ending.

The number refers to the carbon atom to which the functional group is attached.

The chain is numbered starting at the end that will give the smallest number to the group.

Sometimes, the functional group can only be in one place, so no need for the position number…

NOTE: For this structure, carbon chain starts from the right hand side, so that the number of the group will be 1 and not 3…

Main Menu

Rule 3: Identify the side chains or substituent groups Side chains, or functional groups in addition to the one used as the suffix, are

known as substituents, and are given as the first part or prefix of the name.

Note: Amine –NH2 can appear as both a suffix and a prefix. Usually when it is the only functional group it will take the suffix. When there are two or more, it will be the prefix (see above example).

Main Menu

If there is more than one substituent group of the same type, we use commas between the numbers and the prefixes di-, tri-, or tetra- before the name.

Substituents are given in the order of the number of the carbon to which they are attached.

If there is more than one group on the same atom, they are put in alphabetical order.

Numbering starts from the end that gives a smaller number…

Main Menu

Summary IUPAC nomenclature has three possible parts, which are

usually written together as a single word.

Main Menu

Solutions

Main Menu

Main Menu

Main Menu

Main Menu

Thinking About Formulas

Produce a table to summarise each of the types of formulas. Include columns for: What they show Pros Cons How you make them

Draw full structural, condensed structural and skeletal formulas for at least 5 of the C4H8O compounds (not the cyclic ones)

Main Menu

Key Points

Organic chemistry is the chemistry of carbon containing compounds

A homologous series is a family of organic compounds differing only by the length of their carbon chains

The melting and boiling point increases as you go down a homologous series

Displayed formulas show the unambiguous arrangement of atoms in a compound