Structure of Organic Compounds

Question 1

Alkane

Answer 1

No functional group: Single bonds between C atoms
Formula: C(n)H(2n+2)
Example: Methane

Question 2

Alkene

Answer 2

Functional group: At least one double bond between C atoms
Formula: C(n)H(2n)
Example: Prop-2-ene

Question 3

Alkyne

Answer 3

Functional group: At least one triple bond between C atoms
Formula: C(n)H(2n-2)
Example: Prop-2-yne

Question 4

Alcohol

Answer 4

Functional group: Hydroxyl (OH-)
Formula: Cn H2n O
Number from end closest to functional group
Suffix: Ol
Example: butan-2-ol

Question 5

Aldehyde

Answer 5

Functional group: Carbonyl group (C double bond O) on terminal carbon. C double bond is always first carbon in naming
Formula: Cn H2n O
Suffix: al
Example: propanal

Question 6

Ketone

Answer 6

Functional group: Carbonyl group (C double bond O) on non-terminal carbon
Formula: Cn H2n O
Suffix: one
Example : pentan-3-one

Question 7

Carboxylic acid

Answer 7

Functional group: Carboxyl group (C double bond O, OH)
Carboxyl is always on carbon 1
Formula: Cn H2n O2
Suffix: oic acid
Example: butanoic aid

Question 8

Hydrocarbon

Answer 8

An organic compound consisting of only carbon and hydrogen atoms.

Question 9

Prepositions for naming

Answer 9

Meth, eth, prop, but, pent, hex, hept, oct, non, dec

Question 10

Haloalkane

Answer 10

Contains at least one halogen (group 17) off a carbon
Number chain so halogen is attached to lowest carbon number
Halogen stem ends in ‘o’ and placed before alkane with location
Example: 2-chloropropane

Question 11

Branched molecules

Answer 11

Branches are called side chains
End in ‘yl’
Example: 2,3-dimethylbutane

Question 12

Cyclic molecules

Answer 12

Cyclic hydrocarbon has a ring of hydrocarbons and cyclo as a prefix
Ring is the main chain if it has the most carbons otherwise it is a cycloalkyl group
If there is only one branch or double/triple bond it doesn’t need to be numbered
Number the ring so functional group is number 1
If multiple branches, number carbon to give lowest combination of numbers
Example: 1-ethyl-3-methylcyclopentane

Question 13

Amines

Answer 13

Functional group: NH2
Suffix: amine
Example: Propan-1-amine

Question 14

Nitrile

Answer 14

Functional group (C triple bond N)
Nitrile carbon is number 1
Suffix: nitrile
Example: propane nitrile

Question 15

Esters

Answer 15

Functional group: (C double bond O, single bond O)
Formed by the reaction of a carboxylic acid and an alcohol
suffix: oate

Question 16

Functional group

Answer 16

An atom or group of atoms that gives a characteristic set of properties to a molecule containing those atoms

Question 17

Amide

Answer 17

C double bond O, single bond N-H2

Question 18

Determination of an alkene

Answer 18

The presence of a carbon double bond is determined using bromine water. The bromine solution becomes colourless in the presence of an alkene. Potassium permanganate also decolourises in the presence of a double bond.

Question 19

Colour change in bromine water with saturated vs unsaturated compounds

Answer 19

Unsaturated compounds cause a colour change
Saturated compounds do not cause a colour change