Alcohols Flashcards
What is the functional group of alcohols?
-OH
What is the difference between structural and displayed formula?
Structural: The written way of showing every single atom, with what its bonded to, going from left to right
Eg: Methanol: CH₃OH
Displayed: The displayed or drawn molecule
Eg: Methanol
H
|
H - C - O - H
|
H
What are the 2 different methods of making pure ethanol?
-Fermentation of sugar
-Hydration of ethene
What is the equation for the fermentation of sugar?
C6H12O6 -> 2C2H5OH + 2CO2
What 4 factors do you need to make ethanol from fermenting sugar?
-A sugar solution
-Yeast
-A temperature of about 30°C
-An air trap for the equipment to keep oxygen out
What is the biology behind the fermentation of sugar to make ethanol?
There is anaerobic respiration by yeast, which is also a biological catalyst.
What separating method do you use to separate water and ethanol once you ferment sugar?
Why?
Fractional distillation.
Because ethanol evaporates at a lower temperature to water.
What is the chemical equation for the hydration of ethene to make ethanol?
C2H4 + H2O -> C2H5OH
What is the word equation for the hydration of ethene to make ethanol?
Ethene + steam -> pure ethanol
What is the catalyst needed when hydrating ethene to make ethanol?
Phosphoric acid.
What 4 factors do you need to make ethanol from hydrating ethene?
-Ethene mixed with steam
-A pressure of 60-70 atmospheres
-A temperature of about 300°C
-The mixture passing through a catalyst of phosphoric acid
Why type of reaction is required to make ethanol from ethene?
Hydration.
Why does the hydration of ethene require lots of energy?
To break the carbon double bond.
What is the rate of the reaction in fermentation of sugar?
Slow.
What is the rate of the reaction in hydration of ethene?
Fast.
What is the product quality like of fermenting sugar to make ethanol?
It must be purified to separate the water from the ethanol, using fractional distillation.
What is the product quality like of hydrating ethene to make ethanol?
Pure.
Is there use of finite resources in the fermentation of sugar to make ethanol?
No, it uses replaceable sugar.
Is there use of finite resources in the hydration of ethene to make ethanol?
Yes, it uses non-renewable oil.
What is the word equation for the microbial oxidation of ethanol?
Ethanol + Oxygen -> Ethanoic Acid + Water
What usually causes the oxidation of ethanol?
Yeast cells.
What is ethanoic acid also known as?
Vinegar.
What is the chemical equation for the oxidation of ethanol?
C2H5OH -> C2H3OOH
What are the 3 optimum conditions for the microbial oxidation of ethanol?
-About 30°C
-Presence of yeast
-Presence of oxygen
What are the 3 types of oxidation of ethanol?
-Complete combustion (burning in air or oxygen)
-Microbial oxidation (reaction with oxygen in the air to form ethanoic acid)
-Chemical oxidation
What is the word equation for the combustion of ethanol?
Ethanol + Oxygen -> Carbon dioxide + Water
What happens if there is insufficient oxygen in the combustion of ethanol?
It will lead to incomplete combustion and carbon monoxide formed instead of carbon dioxide.
Define microbial oxidation:
Microbes using oxygen in air to oxidise alcohols for energy source (producing ethanoic acid).
What 2 other substances are required in the chemical oxidation of ethanol?
-Potassium dichromate (VI)
-Dilute sulfuric acid
What is formed in chemical oxidation of ethanol?
Ethanoic acid.
What is the chemical formula for potassium dichromate (VI)?
K2Cr2O7
What is the chemical formula for sulfuric acid?
H2SO4
What is the colour change in the chemical oxidation of ethanol?
Orange -> Green
Ethanol + Oxygen -> ?
Ethanol + Oxygen -> Ethanoic Acid + Water
What is the definition of an isomer?
When molecules have the SAME molecular formula, but DIFFERENT displayed formulas.
