Organjc Chemistry Part 2 Flashcards
(105 cards)
What is the general formula of an alcohol
CnH2n+1OH
What are the three ways that you can oxidize ethanol
By combustion
By microbial/aerobic oxidation
With an oxidizing agent (like potassium dichromate (IV) in sulfuric acid)
Give the word equation of the combustion of ethanol
Ethanol + oxygen —-) carbon dioxide + water
Give the balanced symbol equation of the combustion of ethanol
C2H5OH(l) + 3O2(g) ——) 2CO2(g) + 3H2O(l)
What type of fuel is ethanol and what are examples of what it is made of
A biofuel
Made of for example corn or sugar cane
Explain why wine has a sour taste after a few days of being open
Microorganisms in the wine use the oxygen in the atmosphere
to oxidize the ethanol
Into ethanoic acid
Where the acid gives the wine it’s sour taste
Which oxidizing agent can be used to form ethanoic acid, from ethanol
potassium dichromate (IV) acidified in dilute sulfuric acid
Give the symbol equation of potassium dichromate (IV)
K2Cr2O7
State what is oxidized and what is reduced in the oxidation reaction of ethanol using an oxidizing agent
Ethanol is oxidized
Potassium dichromate is reduced
When ethanol is oxidized using an oxidizing agent, state what the colour change is and why
Orange to green
And is Green because of the presence of Cr^3+ions
Give the oxidation equation of ethanol being oxidized using an oxidizing agent
CH3CH2OH + 2[O] ——) CH3COOH + H2O
(Always use the structural formula to show alcohols)
One way to set up the experiment for oxidizing ethanol with an oxidizing agent is to use a vertical condensing jacket in top of a flask. Explain why the condensing jacket is there
Because some of the volatile components of the ethanol may evaporate quickly,
So the condensing jacket condensed this back into a liquid so that the solution can boil for longer
How would éthanol production be affected if sugar and yeast were left in an environment with oxygen
Ethanol would not be produced because instead, the yeast would respire aerobically
And would produce carbon dioxide and water instead
Or then the oxygen would react with the ethanol produced to make ethanoic acid, giving the drink a sour taste
What are the two ways that ethanol can be produced
By fermentation
Or hydration of ethene
Give the word equation to produce ethanol from fermantion
Glucose—-(yeast)—) ethanol + carbon dioxide
Give the balanced symbol equation to produce ethanol from fermentation
C6H12O6—-(yeast)——-) 2C2H5OH + 2CO2
Explain how to produce ethanol from fermentation (5)
1)place sugar/starch in water and then add yeast
2)heat to 30 degrees and make conditions anaerobic
3)the enzymes in the yeast will ferment the sugars , to produce ethanol and carbon dioxide
4) when ethanol concentration reaches 15% the yeast is killed, so vessel should be emptied for a new batch
5) the ethanol produced needs to be fractionally distilled to produce a pure sample
Why can alcoholic drinks never have more than 15% alcohol concentration
Because when the ethanol produced in the fermentation process reaches 15% concatenation it kills the yeast, and so the sugar can no longer be broken down to produce ethanol
What is the temperature and catalyst used to produce ethanol from fermentation
30 degrees temperature
And
Enzymes in the yeast
Give the balanced symbol equation to produce ethanol from the hydration of ethene
(In terms of molecular formula)
C2H4(g) + H2O(g) —-) C2H5OH(l)
What type of reaction is the hydration of ethene and why
Addition, because atoms are being added, and none are being removed
Give the balanced symbol equation of producing ethanol from the hydration of ethene
(In terms of structural formula)
CH2=CH2 (g) + H2O (g)—-) CH3CH2OH(l)
Explain Why may you have to use fractional distillation after carrying out the hydration of ethene to produce ethanol
Because the process produces ethanol, water and unreacted ethene
So fractional distillation is used to take a pure sample of ethanol
Which takes advantage of how ethene has a much lower boiling point than both water and ethanol
What is the temperature,
catalyst,
And pressure used, when carrying out the hydration of ethene
Temperature is 300 degrees
Catalyst is phosphoric acid
Pressure is 60-70 atmospheric pressure