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International Baccalaureate IB Chemistry
3.2.1 Different types of organic formulas
Organic compounds can be represented by different types of formulas. These include empirical, molecular, structural (full and condensed), stereochemical and skeletal. Identify different formulas and interconvert molecular, skeletal and structural formulas. Construct 3D models (real or virtual) of organic molecules.
3.2.2 Functional groups and their properties
Functional groups give characteristic physical and chemical properties to a compound. Organic compounds are divided into classes according to the functional groups present in their molecules. Identify the following functional groups by name and structure: halogeno, hydroxyl, carbonyl, carboxyl, alkoxy, amino, amido, ester, phenyl.
3.2.3 Homologous series
A homologous series is a family of compounds in which successive members differ by a common structural unit, typically CH₂. Each homologous series can be described by a general formula. Identify the following homologous series: alkanes, alkenes, alkynes, halogenoalkanes, alcohols, aldehydes, ketones, carboxylic acids, ethers, amines, amides and esters.
3.2.4 Melting & Boiling Point Trends
Successive members of a homologous series show a trend in physical properties. Describe and explain the trend in melting and boiling points of members of a homologous series.
3.2.5 IUPAC nomenclature
“IUPAC nomenclature” refers to a set of rules used by the International Union of Pure and Applied Chemistry to apply systematic names to organic and inorganic compounds. Apply IUPAC nomenclature to saturated or mono-unsaturated compounds that have up to six carbon atoms in the parent chain and contain one type of the following functional groups: halogeno, hydroxyl, carbonyl, carboxyl.
3.2.6 Structural isomers
Structural isomers are molecules that have the same molecular formula but different connectivities. Recognise isomers, including branched, straight‑chain, position and functional‑group isomers.
3.2.7 Stereoisomers and chirality
Stereoisomers have the same constitution (atom identities, connectivities and bond multiplicities) but different spatial arrangements of atoms. Describe and explain the features that give rise to cis‑trans isomerism; recognise it in non‑cyclic alkenes and $C_3$ and $C_4$ cycloalkanes. Draw stereochemical formulas showing the tetrahedral arrangement around a chiral carbon. Describe and explain a chiral carbon atom giving rise to stereoisomers with different optical properties. Recognise a pair of enantiomers as non‑superimposable mirror images from 3D modelling (real or virtual).
3.2.8 Mass spectrometry of organic compounds
Mass spectrometry (MS) of organic compounds can cause fragmentation of molecules. Deduce information about the structural features of a compound from specific MS fragmentation patterns. Include reference to the molecular ion.
3.2.9 Infrared (IR) spectroscopy
Infrared (IR) spectra can be used to identify the type of bond present in a molecule.
Interpret the functional‑group region of an IR spectrum, using a table of characteristic frequencies (wavenumber $\mathrm{cm}^{-1}$).
Include reference to the absorption of IR radiation by greenhouse gases.
3.2.10 ¹H NMR Spectra to Determine Organic Structures
Proton nuclear magnetic resonance spectroscopy ([1] H NMR) gives information on the different chemical environments of hydrogen atoms in a molecule. Interpret[1] H NMR spectra to deduce the structures of organic molecules from the number of signals, the chemical shifts, and the relative areas under signals (integration traces).
3.2.11 ¹H NMR – splitting patterns
Individual signals can be split into clusters of peaks.
Interpret $^1\text{H}$ NMR spectra from splitting patterns showing singlets, doublets, triplets and quartets to deduce greater structural detail.
3.2.12 Combining spectroscopic data
Data from different techniques are often combined in structural analysis. Interpret a variety of data, including analytical spectra, to determine the structure of a molecule.