C7.2 Alcohols Flashcards
1
Q
- What are names of the first two alcohols?
A
-ethanol, methanol
2
Q
- What is the molecular formula of ETHANOL?
A
C2H5OH
3
Q
- What is the molecular formula of METHANOL?
A
CH3OH
4
Q
- What is the general formula of alcohols?
A
CnH2n+1OH
5
Q
- What is the functional group of alcohols?
A
-OH
6
Q
- What causes the characteristic properties of alcohols?
A
-the presence of the –OH functional group
7
Q
- How does ethanol compare in its physical properties with water and with alkanes?
A
- soluble in water: alcohol (ethanol)
- good solvent: alcohol (ethanol), water
- boiling point: higher than alkanes but lower than water
- state at room temperature: alcohol= volatile liquid, water= liquid, alkane= volatile gas
8
Q
- What happens when alcohols burn in air?
A
-they produce carbon dioxide and water because of the presence of a hydrocarbon chain
9
Q
- What are the reactions of sodium with ethanol, water and alkanes?
A
- sodium + ethanol → sodium ethoxide + hydrogen
- sodium + water → sodium hydroxide + hydrogen
- sodium + alkanes DON’T REACT
10
Q
- Why is there a limit to the concentration of ethanol solution that can be made by fermentation?
A
-when concentration of ethanol reaches 10-20% the yeast is killed by the ethanol so reaction stops
11
Q
- What product is usually made by the process of formation to make ethanol?
A
-alcoholic drinks
12
Q
- What is the process of producing ethanol by fermentation?
A
- yeast converts sugars into ethanol (+carbon dioxide)
- enzyme zymase in yeast cells acts as catalyst for fermentation
13
Q
- Why is it important to prevent oxygen getting into the fermentation process?
A
-oxygen converts ethanol into ethanoic acid= lower pH= enzymes stop working
14
Q
- What happens when the fermented mixture is distilled?
A
-more concentrated ethanol solution= brandy/whisky
15
Q
- What is the process of distillation?
A
- ethanol solution in flask below fractioning column
- solution heated= ethanol boils
- ethanol vapour travels up and cools
- anything with higher boiling point than ethanol cools and flows back to liquid= only pure ethanol reaches top column
- ethanol vapour flows through condenser- cooled into liquid and collected