4 Organics 2 Flashcards
Use the method below to name the ester made from ethanol and methanoic acid
ethyl methanoate
Esters are very volatile (evaporate easily) and smell or taste sweet. What are esters used for?
fragrances in perfumes OR flavourings in food
What conditions are needed for microbial oxidation of ethanol?
Oxygen so that aerobic respiration can occur
30ºC
1 atm
Formation of ethanoic acid - vinegar
Name the homologous series
carboxylic acid
How do you know that the formation of ethanoic acid from ethanol is oxidation?
ethanol has gained oxygen
What are the conditions needed in a fermenter?
30ºC
1 atm
no oxygen
What type of reaction is shown below?
Complete combustion of ethanol
It is an exothermic reaction
Draw the structural formula of ethanol
What are products for the reaction between ethanoic acid and sodium carbonate
metal carbonate + acid –> salt + water + carbon dioxide
Describe the conditions for fermentation of glucose
30ºC
yeast
1 atm
no oxygen (anaerobic)
Name this molecule
-O-H group - therefore it is an alcohol
4 carbons
butan-1-ol
Which homologous series does this molecule belong to?
alcohol
Name the molecule
methanol
What are the disadvantages of the addition of of ethene to make ethanol?
- expensive process - (high temp and pressure)
- non-renewable ethene is needed
- very technical process - needing expertise.
What are the advantages and disadvantages of food such as corn being made into fuel (alcohol)?
Advantage: it is renewable
Disadvantage: It uses up land that would normally be used to grow food for people- this increases food prices
Draw the dot cross diagram for ethanol
Draw the displayed formula of ethanol
Complete the word equation for fermentation of glucose with yeast
glucose –> ethanol + carbon dioxide
Draw the displayed formula for propan-1-ol
Name the ester
ethyl hexanoate
Name the ester
ethyl butanoate
What is the molecular formula of glucose?
C6H12O6
What conditions are needed to oxidise ethanol
potassium dichromate VI - oxidising agent
conc. sulfuric acid - catalyst
heat
NOT|E: mixture will turn from yellow to green
Describe how to safely make and smell an ester from ethanoic acid and propanol
- Place six drops of concentrated sulfuric acid into a test tube
- Add 1 cm3 of ethanoic acid
- Add 1 cm3 of propanol
- Swirl gently and add the test tube to a hot water bath
- Leave for 5 minutes
- Pour the mixture into a beaker of sodium carbonate to neutralise the concentrated acid
- Carefully waft the fumes towards your nose to identify the sweet ester smell
Name the ester
ethyl propanoate
Name the alcohol
propan-1-ol
Name the products of anaerobic respiration of glucose by yeast
ethanol and carbon dioxide
Name the functional groups which are identified on this molecule
red = carboxylic acid (COOH)
green = ester (RCOOR’)
Name the two homologous series
alkane
AND
alcohol
List the products of the following reaction
ethanol
carbon dioxide
What is the name of the container and cap needed for small scale fermentation of glucose AND explain why the special cap is needed.
Demijohn with a swan neck
Swan neck allows CO2 out (prevents it from exploding from pressure) but also stops oxygen from entering so that only anaerobic respiration of yeast occurs
What is the function of potassium dichromate (VI) in the oxidation of alcohols
potassium dichromate (VI) is the oxidising agent
It supplies oxygen [O]
It, itself is reduced
What are the advantages of making ethanol by addition of ethene using steam?
- no land needed to grow sugar cane
- fast, continuous process
- pure product of ethanol (100%)
Name the products made from:
sodium carbonate and ethanoic acid
AND potassium metal added to propanoic acid
sodium hydroxide + ethanoic acid –> sodium ethanoate + water + carbon dioxide
potassium + propanoic acid –> potassium propanoate + hydrogen
Describe the condition for the addition reaction of ethene to ethanol
ethene + steam
300ºC
Phosphoric acid catalyst
60 atm
What are the disadvantages of making ethanol by fermentation?
- need land to grow sugar cane (reactant)
- product is not 100% pure - (Only 14% since yeast dies)
- slow, batch process
- CO2 is produced which is a green house gas
What are the advantages of the fermentation process to make ethanol?
- uses a renewable source - such as sugar cane
- cheap process - only 30ºC, no pressure
- little technology needed to make it
Identify the homologous series
ester
Why is ethanoic acid a weak acid?
ethanoic acid does not fully dissociate into H+ ions
Only 4 in 100 molecules dissociate - less H+ ions = weaker acid
Name the homologous series depicted below
Carboxylic acid
What type of reaction is esterfication?
Condensation reaction
(water condenses out) leaving a carbon-oxygen bond between the carboxylic acid and alcohol
Use the method below to name the ester made from propan-1-ol and butanoic acid
propyl butanoate
In the process of fermentation, ethanol levels reach 14% before the yeast dies. How could ethanol be purified to 100%.
distillation
Use the method below to name the ester made from
butan-1-ol and propanoic acid
butyl propanoate
What are the observations and products formed when magnesium is added to ethanoic acid
slight fizzing (as ethanoic acid is a weak acid)
magnesium ethanoate + hydrogen
Test for hydrogen- flaming splint goes squeaky pop
Name the identified functional groups on this molecule
OH = alcohol
COOH = carboxylic acid
What would happen if fermentation of glucose was carried out in the presence of oxygen or aerobically?
ethanol would oxidise to ethanoic acid
Name this salt
sodium ethanoate
