4.1: Know that a Hydrocarbon is a Compound of Hydrogen and Carbon Only

HYDROCARBON: Compound that only contains Hydrogen and Carbon atoms

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Example:

Diagram showing Hydrocarbons - Methane, Ethane and Propane

4.2: Understand How to Represent Organic Molecules using Empirical Formulae, Molecular Formulae, General Formulae, Structural Formulae and Displayed Formulae

DEFINITIONS:

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TERM	DEFINITION
EMPIRICAL FORMULAE	Ratio of atoms of each element in compound in simplest form (whole number)
MOLECULAR FORMULAE	Chemical formula showing the elements and number of atoms of each element in compound
GENERAL FORMULAE	Formula that states the ratio of atoms of each element in formula of every compound in specific homologous series
STRUCTURAL FORMULAE	Formula that states the number of atoms of each element in compound and the bonds that join them together (straight lines representing covalent bonds)
DISPLAYED FORMULA	Formula that graphically shows the number of atoms of each element in compound and the bonds that join them together (straight lines representing covalent bonds)

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Example: Ethene (C2H4)

DESCRIPTION	FORMULA
EMPIRICAL FORMULAE	CH2
MOLECULAR FORMULAE	C2H4
GENERAL FORMULAE	CnH2n
STRUCTURAL FORMULAE	CH2 = CH2
DISPLAYED FORMULA

4.3: Know What is Meant by the Terms Homologous Series, Functional Group and Isomerism

DEFINITIONS:

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HOMOLOGOUS SERIES: A Series of Organic Compounds that has Similar Features:

FEATURES
- Same general formula	- Same functional group
- Similar chemical reactions	- Physical properties show gradation
- Each member differs from the next by a  CH2 Unit

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FUNCTIONAL GROUP: Group of atoms bonded in specific arrangement that makes compound behave in particular way

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NAME	FUNCTIONAL GROUP	FAMILY
… ane	None	Alkane
… ene	C = C Bond	Alkene
… anol	O - H Group	Alcohol
… anoic Acid	C - O - O - H Group	Carboxylic Acid
… anamine	NH2 Group	Amine

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ISOMERISM: Compounds that have same molecular formula but different displayed formulae

Example:

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BUTANE	METHYLPROPANE
C4H10	C4H10

4.4: Understand How to Name Compounds Relevant to this Specification Using the Rules of International Union of Pure and Applied Chemistry (IUPAC) Nomenclature

NAMING COMPOUNDS:

Example:

METHANE	PROPANE	ETHENE

PROPENE	ETHANOIC ACID	ETHANOL

4.5: Understand How to Write the Possible Structural and Displayed Formulae of an Organic Molecule Given its Molecular Formula

DISPLAYED FORMULA: Formula that graphically shows the number of atoms of each element in compound and the bonds that join them together (straight lines representing covalent bonds)

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Example: Ethene ( C2 H4 )

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From the molecular formula, we know that Ethene has 2 Carbon atoms and 4 Hydrogen atoms:

STRUCTURAL FORMULA: Formula that states the number of atoms of each element in compound and the bonds that join them together (straight lines representing covalent bonds)

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Example: Ethene

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Displayed formula of Ethene can be split up into sections and written as a formula:

Diagram showing the Conversion of Displayed Formula into a Structural Formula

OTHER EXAMPLES:

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MOLECULAR FORMULA	STRUCTURAL FORMULA	DISPLAYED FORMULA
METHANE CH4	CH4
PROPANE CH8	CH3 CH2 CH3
ETHENE C2H4	CH2 = CH2
ETHANOL C2H5OH	CH3 CH2 OH

4.6: Understand How to Classify Reactions of Organic Compounds as Substitution, Addition and Combustion

SUBSTITUTION REACTION: Reaction where one atom is swapped with another atom

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Example: Methane reacts with Bromine under Ultraviolet Light

Methane   +   Bromine   →   Bromomethane   +   Hydrogen Bromide             CH4                 Br2                      CH3Br                            HBr

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ADDITION REACTION: Reaction in which one molecule combines with another to form a single larger molecule

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Example: Bromine will react with Ethene by Bromine molecule adding across the double bond of Ethene

Ethene   +   Bromine   →   Dibromoethane           C2H4                 Br2                      C2H4Br2

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COMBUSTION REACTION: Chemical reaction involving burning

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Example: Alkenes burn when heated in Air of Oxygen

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If there is an unlimited supply of Oxygen, combustion reaction (complete combustion) will produce Carbon Dioxide and Water:

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CH4   +   2O2   →   CO2   +   2H2O        C3H8   +   5O2   →   3CO2   +   4H2O

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If there is a limited supply of Oxygen, combustion reaction (incomplete combustion) will produce Carbon Monoxide and Water:

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CH4   +   ½ O2   →   CO   +   2H2O