Fragrances

Question 1

Describe the term essential oil and state its properties and uses

Answer 1

Essential oils are concentrated extracts of volatile, non-water soluble aroma compounds, which come from plants.

They are volatile, non-water soluble.

Often used in perfumes, cosmetic products, cleaning products and as flavourings.

Question 2

Describe and recognise a terpene

Answer 2

Terpenes are unsaturated hydrocarbons. They are made from isoprene (2-methylbuta-1,3-diene) units bonding together.

They can be recognised by the compound only containing isoprene units.

Question 3

State what happens when terpenes are oxidised

Answer 3

When oxidised, terpenes release the distinctive aroma found in spices (such as ginger and cinnamon)’ they don’t need to know any more detail as to what actually happens to the molecule.

Question 4

Recognise an isoprene unit and state the number of isoprene units in a terpene molecule

Answer 4

2-methylbuta-1,3-diene=Isoprene unit

To state the number of isoprene’s in a terpene: Count the number of carbon atoms and divide by 5 (15 carbon atoms, 3 isoprene units).