3.3.5.1 Alcohol production Flashcards Preview

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Flashcards in 3.3.5.1 Alcohol production Deck (16)
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1
Q

Why do alcohols have higher melting point than alkanes of the same length?

A

OH in alcohols causes hydrogen bonding which increases the intermolecular forces. Therefore more energy is needed to overcome these forces which increases the melting point

2
Q

Are alcohols soluble?

A

The OH group of alcohols can hydrogen bond to water molecules but the non-polar hydrocarbon chain cannot, so alcohols with short chains are soluble

3
Q

How is ethanol produced from cracking?

A

Ethene is produced when crude oil fractions are cracked
Ethene is hydrated which means that water is added across the double bond
Phosphoric acid catalyst

4
Q

How is ethanol produced by fermentation?

A

Glucose = Ethanol + Carbon Dioxide
Carbohydrates broken down into sugars
Converted into ethanol by yeast
Carbohydrates come from crops e.g. sugar cane
Anaerobic respiration
35 degrees celcius: too low would be slow, too high would denature the enzyme
Air kept out to stop ethanol from being oxidised to ethanoic acid
At 15% ethanol, enzymes are unable to function. Ethanol can be distilled by fractional distillation

5
Q

What is the formula for glucose?

A

C6H12O6

6
Q

What is the process of making ethanol from crude oil with mechanisms?

A

See card
Step 1: from the double bond to the hydrogen ion
Step 2: from electronegative oxygen to positive carbon atom
Step 3: from O - H bond to oxygen atom
Forms ethanol plus hydrogen

7
Q

What are the advantages and disadvantages of biodiesel?

A

Releases less carbon dioxide than mineral diesel from crude oil
Fully degradable so is less damaging when spilt
Not carbon neutral as energy is required for processing, farming and fertiliser manufacture
More expensive to produce than fossil fuels

8
Q

What are the advantages and disadvantages of bioethanol?

A

CO2 release is lower than fossil fuels
Renewable
Less energy dense than petrol
Cutting down trees to provide area for growing plants destroys wildlife

9
Q

What are the advantages and disadvantages of hydrogen?

A

The only product is water so there are no polluting gases
It is an infinite resource
It is expensive to electrolyse water
Electricity is required to produce hydrogen

10
Q

What are the properties of alcohols?

A

Normally polar molecules
Soluble in water
High melting/boiling points compared to alkenes/alkanes of a similar size

11
Q

What is the primary, secondary and tertiary structures of alcohols?

A

See card

12
Q

Fuel cells

A

Produce electricity from the reaction between hydrogen and oxygen
Efficient at transferring the energy of the reaction
Cars with fuel cells are expensive

13
Q

What is the reaction between alkenes and steam?

A

Alkene + H2O = Alcohol

14
Q

What are the conditions for the reaction between ethene and steam?

A

Ethene + steam (+ phosphoric acid catalyst) = ethanol

15
Q

What is the reaction for anaerobic respiration?

A

C6H12O6 ( + yeast ) = 2C2H5OH + 2CO2

16
Q

What are the conditions for the breakdown of glucose?

A

Rate is affected by temperature
Enzyme denatures at high temperatures
Air kept out to prevent oxidation so that ethanoic acid is not produced
Ethanol is extracted by fractional distillation

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