Other functional groups (Separate chemistry 2) Flashcards
a) Draw the structure of a molecule of propanol, C[3]H[7]OH.
Show all the covalent bonds. [1]
b) Predict the products of the complete combustion of propanol. [2]
a) three Cs and an O in the middle chain
- two hydrogens to every carbon except the end one, which has three
- one carbon attached to the oxygen
b) CO2 and water vapour
The formula for butanol (also called butan-1-ol) can be shown as C4H9OH
a) Explain how you know that butanol is a member of the alcohol homologous series. [2]
b) Draw the structure of a molecule of butanol.
Show all the covalent bonds. [2]
c) Write a balanced equation for the complete combustion of butanol. [2]
a) the members of a homologous series all have the same functional group, in alcohols this is the -OH group, which butanol contains
b) middle chain: H-C-C-C-C-O-H
rest of Hs attached above and below to the Cs
c) C[4]H[9]OH + 6O[2] -> 4CO[2] + 5H[2]O
Explain why the fermentation mixture must be kept warm and under anaerobic conditions when making ethanol. [4]
the reaction is too slow at low temperatures and the yeast enzymes don’t work at high temperatures
fermentation is a type of anaerobic respiration
if oxygen is present, aerobic respiration happens instead, producing only CO2 and water
Ethanol is produced by fermentation.
a) Write a balanced equation for this process, including state symbols. [3]
b) Describe the catalyst used for this process. [2]
c) Suggest a suitable temperature for carrying out fermentation. [1]
Explain how concentrated ethanol is obtained from the fermentation mixture. [2]
fractional distillation is used because water and ethanol are liquids with different boiling points
a) Draw the structure of a molecule of propanoic acid, C[2]H[5]COOH.
Show all the covalent bonds. [2]
b) Name the alcohol that can be oxidised to produce propanoic acid. [1]
a) main chain: H-C-C-C-O-H
the 3rd C is connected via double bond to the O
the rest of the Hs are connected to the first 2 Cs
b) propanol
The formula for butanoic acid is C[3]H[7]COOh.
a) Explain how you would know that butanoic acid is a member of the carboxylic acid homologous series. [2]
b) Draw the structure of a molecule of butanoic acid. Show all the covalent bonds. [2]
c) Name the alcohol that can be oxidised to produce butanoic acid. [1]
a) its formula contains the -COOH/carboxyl group and this is the functional group found in carboxylic acids
b) main chain: H-C-C-C-C-O-H
O connected to the 4th C by double bonds
the rest of the Hs are connected to the first 3 Cs
c) butanol/butan-1-ol
A student uses spirit lamps and a calorimeter to investigate the use of four alcohols as fuel.
State four factors, other than the alcohol and the mass of water used, that could affect the temperature rise observed. [4]
height of calorimeter above the flame
size/height of the flame
lid/no lid on the calorimeter
use of insulation on size of calorimeter
starting temperature of the water/temperature of the room
heating time
draughts
