CSEC Introduction to Organic Chemistry

CSEC

Organic chemistry

Introduction

Introduction to Organic Chemistry

https://www.youtube.com/watch?v=PmvLB5dIEp8

Organic Chemistry

• The study of Carbon containing compounds excluding the inorganic ones

(CO2, CO, carbonates, hydrogencarbonates etc).

• Carbon is singled out because it has a chemical diversity unrivaled by any

other chemical element. As a result there is large number of organic
compounds based on the following characteristics of carbon:

Catenation

Carbon atoms bond reasonably strongly with other carbon atoms, this is catenation.

Multiple Choice

Carbon can form

i. straight chains

ii. branched chains

iii. rings

• i and ii only

• i only

• ii only

• i, ii and iii

Carbon forms bonds with other elements

Carbon can form single, double or triple Bonds

Remember C has a valency of 4,

therefore each C atom must
always have 4 covalent bonds

Multiple Choice

What type of bnds can Carbon form?

i. single

ii. double

iii. triple

iv. quadruple

• i, ii, iii and iv

• i, ii and iii only

• i only

• i and ii only

Formulae

• Molecular formula
• Shows the actual number of atoms in the molecule

• Empirical formula
• Simplest ratio of the various atoms in a molecule (or formula unit)

C2H4

CH

Formulae

• Structural formula
• Shows how the atoms are joined in a molecule

Multiple Choice

For the following molecule, use the key to determine the molecular formula.

Carbon-black

Hydrogen-white

Chlorine-green

• C₂H₄Cl₂

• C₄H₂Cl₂

• C₂H₂Cl₂

• C₂H₄Cl

Multiple Choice

For the following molecule, use the key to determine the EMPIRICAL formula.

Carbon-black

Hydrogen-white

Chlorine-green

• C₂H₄Cl₂

• CH₂Cl

• CHCl

• C₂H₄Cl

Multiple Choice

Methyl benzoate, has molecular formula, C₈H₈O₂. What is its Empirical formula?

• C₈H₈O₂

• C₄H₄O₂

• C₄H₄O

• No options are correct.

Multiple Choice

Butanoic acid, a component found in rancid butter, has the molecular formula shown. Determine its empirical formula.

• C₂H₄O

• C₂H₄O₂

• C₄H₈O₂

• No options shown are correct.

Full/Displayed structural formula

Shows all the atoms and all the bonds (it is a 2 dimensional representation)

Condensed/shortened

Shows the arrangement of the hydrocarbon backbone, omitting the bonds

Full vs condensed

Full vs condensed

Full vs condensed

Multiple Choice

Deduce the condensed structural formula for the full structural formula given.

• CH₃CH₂CH₂ClCH₂

• CH₃CH₂CH₂Cl

• CH₂CH₂CH₂CH₂Cl

• CH₃CH₂CH₂CH₂Cl

Multiple Choice

Deduce the condensed structural formula for the full structural formula given.

• CH₃CHCHCH₃

• CH₃CH₂CH₂CH₃

• CH₃CHCHCH₂CH₃

• CH₃CH₂CHCH₂CH₃

General formula

• Numerical relationship between the different atoms in a molecule

• If a general formula for a family of compounds is CnH2n this means that if

the molecules contains 3 carbon atoms, it will contain 6 H atoms as well.
• CnH2n+2
• CnH2n-1 OH

Multiple Choice

If a compound has a general formula C_nH_2n+2, what would be its molecular formula if it has 5 carbon atoms?

• C₅H₁₀

• C₅H₈

• C₅H₁₂

• No options are correct.

Multiple Choice

If a compound has a general formula C_nH_2n+1OH what would be its molecular formula if it has 8 carbon atoms?

• C₈H₁₇OH

• C₈H₁₆OH

• C₈H₁₅OH

• No options are correct.

Homologous groups/series

• Organic compounds are so numerous and diverse that they are put into

families or groups to make their study easier. Members of a group
differ from each other by a methylene group (-CH2).

Properties of homologous

groups

o There is a gradation in physical

properties as members get larger
(i.e. as Number of C atoms
increases)

o e.g. bpt, mpt, density, solubility

Properties of homologous

groups

o Members have the same general formula
o The same functional group

this is an atom/group of atoms or a bond in
the molecule responsible for the chemical
properties of a compound. Members therefore
have similar chemical properties

Multiple Choice

What properties do members of a homologous group have in common?

i. same molecular formula

ii. same general formula

iii. same functional group

• ii only

• i and ii only

• iii only

• ii and iii only

Homologous Groups

•Alkanes

•Alkenes

•Alkanols (alcohols)

•Alkanoic acids (carboxylic acids)

•Esters