Fundamentals of Organic Chemistry (DP IB Chemistry: SL)

Organic compounds are classified into families called a homologous series.

State three features of members belonging to the same homologous series.

Table 1 shows the boiling points of the first five members of the alkane family.

 Table 1

On the axes below in Figure 1, draw a graph of boiling point against the number of carbon atoms in the alkanes. Estimate the boiling point of the next member of the homologous series, hexane, C₆H₁₄, and show on your graph how you arrived at your estimated boiling point. 

Figure 1

Estimated boiling point of hexane : ________ ^oC

State the general formula for an alkyne and give the molecular formula and name of the fifth member of the alkyne family.

The boiling point of ethyne, C₂H₂, is -84 ^oC.

State with, with a reason, whether the boiling point of ethyne would be expected to be higher or lower than the boiling point of ethane, C₂H₆.

Geraniol is a colourless component of rose oil whose structure is shown in Figure 1.

 Figure 1

Butan-2-ol is an organic compound used industrially to make butanone.

Draw and name all the branched-chain isomers of butan-2-ol.

State, with a reason, the class of alcohols which butan-2-ol belongs to.

The formulae of four organic compounds are given in Table 1. Write the names of the compounds in the second column.

Table 1

Which of the compounds in part (a) are structural isomers of each other and what type of isomerism do they show?

Propofol is a drug used to reduce consciousness during medical procedures. The skeletal structure of propofol is given in Figure 1.

Figure 1

Valeric acid, C₅H₁₀O₂, is a straight chain carboxylic acid found in the plant Valeriana officinalis.

Draw and name all the possible isomers of C₆H₁₄.

Figure 1 below shows a three-dimensional structure of a molecule.                                                  

Figure 1 

Explain the difference between a tertiary haloalkane and a tertiary amine, using suitable diagrams to illustrate your answer.

Three important nitrogen containing functional groups used in chemical synthesis are carboxamides, nitriles and amines.

Draw the Lewis structure of each of these functional groups.

Benzene is an aromatic hydrocarbon which is often drawn as Figure 1.

Discuss the physical evidence that justifies this structure for benzene.

Figure 1

Benzene and cyclohexene are both unsaturated molecules, but cyclohexene reacts with bromine water and benzene does not.

Table 1 below shows the enthalpy changes for the hydrogenation of cyclohexene, benzene, and the theoretical molecule 1,3,5-cyclohexatriene.

Table 1

The equations for the hydrogenation reactions are:

Cyclohexene               C₆H₁₀ + H₂ ⭢ C₆H₁₂

Benzene                      C₆H₆ + 3H₂ ⭢ C₆H₁₂

An unknown aromatic compound has the molecular formula C₈H₈O₂.

Deduce the structural formula of two isomers of this compound which contain an ester group.

State the general formula for carboxylic acids.

State the IUPAC name of the following compound. 

Explain why the solubility of carboxylic acids decreases as chain length increases. 

Propan-2-ol will form an ester when reacted with ethanoic acid in the presence of concentrated sulfuric acid. 

Draw the displayed formula for the ester formed.

State the IUPAC names for the isomers of C₅H₁₂O that are primary alcohols.

State the IUPAC name for the following primary alcohols.

Draw the displayed formula for a straight chain isomer of CH₂(Br)CH(CH₃)CH₂OH.

The empirical formula of the compound in part b) i). 

Draw a diagram to show the resonance structure in a molecule of benzene. 

The energy change for hydrogenation of cyclohexene is -120 kJ mol^-1. However, when benzene undergoes hydrogenation, the energy change is 152 kJ mol^-1 less than expected. 

Use this data to explain the relative stabilities of benzene and the theoretical cyclohexa-1,3,5-triene molecule. 

Phenacetin is a pain killer though the use of this was banned as it was found to cause harm to kidney function.

Deduce the molecular formula of phenacetin. 

Identify the names of the three functional groups present in phenacetin.

Aspirin is a common pain killer and has the following structure.

State the empirical formula of aspirin.

Aspirin is formed from ethanoic anhydride and compound A. State the IUPAC name of compound A.

State the IUPAC names of two branched isomers of C₅H₁₀ that contain a π bond.