Making ethanol

Question 1

difference between spirits and non spirits

Answer 1

spirits have a higher ethanol concentration

Question 2

How are carbohydrates formed?

Answer 2

from carbon, hydrogen and oxygen in fruits/plants

Question 3

fermentation

Answer 3

ethanol is produced from carbohydrates in aqueous solution by fermentation

• fermentation of glucose
• uses enzymes
• produces CO2 and ethanol
• can’t occur in oxygen as yeast fermentation is an anaerobic reaction

glucose -> ethanol + carbon dioxide

Question 4

differences between combustion and fermentation of glucose

Answer 4

combustion:

• in oxygen/aerobic conditions
• doesn’t require enzymes
• doesn’t produce ethanol, but produces CO2 and water
• produces more energy

Question 5

yeast

Answer 5

a single celled fungus that provides enzymes for fermentation to happen

Question 6

Why can fractional distillation be used to obtain a concentrated solution of ethanol (but not pure ethanol)?

Answer 6

• ethanol has a lower boiling point than water

- the small amount of water that remains must be absorbed chemically

Question 7

describe the process of fractional distillation to make ethanol from an ethanol solution

Answer 7

-ethanol solution is heated until it reaches its boiling point and evaporates

• it then rises through the flask into the condenser, where it condenses back to a liquid
• collects in the flask as pure ethanol

-water from solution is left in starting flask as it hasn’t reached its boiling point

• cold water enters the condenser to cool the gas down
• it starts with less energy but more is transferred to it from the gas as it cools down, and the water leaves at a higher temperature with more energy

Question 8

What is fermentation a type of?

Answer 8

anaerobic RESPIRATION