Unit Three: Alcohols

Question 1

What is the general formula for alcohols?

Answer 1

CnH2n+1 OH

Question 2

What is a homologous series?

Answer 2

A group of chemicals that react in a similar way because they have the same functional group (in alcohols = -OH)

Question 3

Name the first three alcohols in the homologous series:

Answer 3

Methanol - CH3 OH
Ethanol - C2H5 OH
Propanol - C3H7 OH

Question 4

What similar properties do the first three alcohols have?

Answer 4

• Flammable - burn in air to produce CO2 and water
• Dissolve completely in water to form neutral solutions
• They react with sodium to give hydrogen and alkoxides

Question 5

Why are alcohols useful?

What are they used for?

Answer 5

Alcohols such as methanol and ethanol can dissolve compounds that water cannot such as hydrocarbons, oils and fats, meaning that ethanol, methanol and propanol are very useful solvents in industry

Ethanol - solvent for perfumes and aftershave lotions 
Methylated spirits (ethanol with chemicals added to it) - used to clean paint brushes and as a fuel

Question 6

Why are alcohols useful?
(What are they used for?)
(Part two)

Answer 6

Fuels:
Ethanol -
used as a fuel in spirit burners can also be mixed with petrol and used as fuel for cars