3.1 An Introduction to AS Level Organic Chemistry

The reaction sequence below shows a pair of reaction types. 

Which row in the table correctly shows the two reaction types?

Which of the following compounds is both chiral and acidic?

The amino acid cysteine performs structural and functional roles within proteins. It is used as a nucleophile in enzymatic reactions and can form disulfide bonds with other cysteine molecules. 

How many carbon molecules in cysteine are sp² hybridised?

The methyl group, CH₃, can exist as an anion, a cation or a free radical. Molecules that contain a methyl group can act as a nucleophile, an electrophile or a free radical depending on the number of outer shell electrons on the methyl carbon atom.

How many outer shell electrons must be present for CH₃ to act in these different ways?

Cholesterol is an important biological molecule produced by the liver. It is used in the production of steroid hormones and vitamin D. 

How many chiral centres are there in one molecule of cholesterol? 

Limonene is found in the peel of citrus fruits.

How many σ and π bonds are present in this molecule?

Including structural and stereoisomers, how many isomeric products are produced when alcoholic NaOH reacts with 2-bromobutane?

How many isomers, including structural and stereoisomers, with the formula C₅H₁₀ have structures that involve π bonding?

Which of the following statements about nucleophiles and electrophiles are always true? 

How many structural isomers are there of tribromopropane, C₃H₅Br₃?

Compound A, an organic compound with a molecular formula C₆H₁₂O₂, is produced by the oxidation of compound B, molecular formula C₆H₁₄O.

Which of the following functional groups does B contain?

How many isomeric esters have the molecular formula C₅H₁₀O₂?

Methyl isocyanate, CH₃NCO, is a toxic liquid which is used in the production of adhesives. 

The sequence of atoms in a methyl isocyanate molecule is H₃C—N=C=O.

What is the approximate angle between the bonds formed by the N atom?

Xylitol is an artificial sweetener used in toothpastes and chewing gum to improve their taste without impairing dental hygiene. 

Which functional groups could be produced if Xylitol is oxidised under suitable conditions? 

A synthetic molecule called N-acetylcysteine is used as an antidote for patients who have ingested too many paracetamol tablets.

The diagram shows part of the molecule N-acetylcysteine and bond angles have been labelled.

Which is the correct size order of bond angles x, y, z from smallest to largest?

11-cis retinal, C₂₀H₂₈O, is found in the retina of animal eyes and is required for vision. 

An 11-cis retinal molecule contains the following functional groups:

• 1 x aldehyde group
• 1 x cyclohexene ring
• 1 x aliphatic side chain

Within the side chain, there is a double bond between carbons 11 and 12.

Which letter is associated with the correct pair? 

	Arrangement of atoms around the adjacent carbons 11 and 12	Total number of carbon-carbon double bonds
A		5
B		6
C		5
D		6

1-chloroethane, CH₃CH₂Cl and NaOH (aq) are reagents in a reaction. 

Which row correctly describes what type of reaction this would be?

Which of the compounds shown have only 1 chiral carbon atom?