Paper 2 Knowledge Gaps: Content
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How is ethanol produced?
Through fermentation
How is ethanol concentrated?
fractional distillation
Write a word equation for fermentation
Glucose –> ethanol + carbon dioxide
What is the formula for ethanol?
C2H50H
Where do the enzymes for fermentation come from?
From yeast cells
State a quick overview of what happens in fermentation
Sugar or starch is dissolved in water and yeast is added
What do the enzymes do in fermentation?
They break down the sugars to alcohol
What does chemically oxidised alcohol produce?
Carboxylic acids
Why must there be an air lock to ferment the ethanol?
To keep the oxygen out as yeast fermentation is a type of anaerobic respiration
What is the highest concentration of alcohol produced by yeast fermentation?
15%
Explain how fractional distillation is used to produce more concentrated solutions of alcohol such as ethanol
• The water and ethanol solution are heated • Ethanol evaporates first as it has a lower boiling point than water, cools then condenses • The water left evaporates, cools then condenses
Write a balanced equation for the formation of ethanol from carbohydrates
C6H12O6 + enzymes → 2CO2 + 2C2H5OH
What is the general formula of a carboxylic acid?
Cn-1H2n+1COOH
State the chemical properties of alcohol
• Produce carbon dioxide and water during complete combustion • can be oxidised to form carboxylic acids • react with reactive metals, forming water as one of the products
Define addition polymerisation
A type of polymerisation in which the monomers add onto each other and no small molecule is eliminated. It only occurs with monomers that contain the double C bond
How do ethene molecules join together to form poly(ethene)?
• They lose the carbon double bond • which then transfers to the sides of each of the carbons to form a repeating unit
How do we deduce the structure of a monomer from the polymer?
• Identify the repeating unit in the polymer • Change the single bond in the repeat unit to a double bond in the monomer • Remove the bond from each end of the repeat unit and the subscript n (which can be placed in front of the monomer)
Define condensation polymerisation
A small molecule is formed as a byproduct each time a bond forms between two monomers
What are the uses of poly(tetrafluoroethene)?
• nonstick coating for frying pans • burette taps • stain proof clothing
What are the properties of poly(tetrafluoroethene)?
• tough • slippery
What are the uses of poly(chloroethene)?
• window frames • gutters • pipes
What are the properties of poly(chloroethene)?
• tough • good insulator • rigid • flexible
What are the uses of poly(propene)?
• buckets • food packaging • ropes
What are the uses of poly(ethene)?
• plastic bags and bottles • cling film