Topic 11 - Alcohols, Carboxylic Acids, Polymers *hard*

Question 1

What is a homologous series?

Answer 1

A group of hydrocarbons that have the same general formula with similar chemical properties.

Question 2

What is a functional group?

Answer 2

A group of atoms responsible for the characteristic reactions of a compound

Question 3

what functional group do alcohols have?

Answer 3

Alcohols are a group of compounds with the functional group -OH

Question 4

general formula of Alcohols

Answer 4

Cn H2n+1 OH

Question 5

dehydration reaction of alcohols

Answer 5

alcohol -> alkene + water

Question 6

what conditions are needed for dehydration reactions

Answer 6

heat and acid catalyst

Question 7

Order of first four alcohols

Answer 7

Methanol , Ethanol, Propanol , Butanol

Question 8

Fermentation

Answer 8

glucose -> ethanol + carbon dioxide
C6H12O6 -> 2C2H5OH + 2CO2

Question 9

Why is yeast mixed to the solution of glucose

Answer 9

Yeast cells contain an enzyme called zymase which catalyses the reaction - speeds it up which makes it suitable for industrial processes

Question 10

Why is the solution kept between 30 and 40 degrees

Answer 10

• Because the rate of fermentation is fastest in these temperatures
• At lower temperatures the reaction is too slow and if the temp is too high the yeast enzymes will denature and won’t catalyse the reaction at all

Question 11

Why do we need to keep the mixture in anaerobic conditions

Answer 11

If the mixture is exposed to oxygen, the ethanol would oxidise to ethanoic acid which is what you get in vinegar

Question 12

How can you keep the reaction anaerobic

Answer 12

add vegetable oil to the top and cover the conical flask with a cotton wool bung

Question 13

When does the fermentation reaction stop?

Answer 13

When the concentration of alcohol reaches about 15% to 20% because the yeast gets killed off by the alcohol and can no longer catalyse the reaction

Question 14

How can you collect a concentrated solution of ethanol

Answer 14

Use filtration to collect the dilute ethanol from the conical flask
use fractional distillation to heat the ethanol vapour
use a liebig condenser to condense the vapour and collect the concentrated ethanol liquid

Question 15

Carboxylic acids functional group

Answer 15

• COOH

Question 16

what do carboxylic acids end in

Answer 16

• anoic

Question 17

What type of acids are carboxylic acids?

Answer 17

Weak acids : they only partially ionise which means they only sometimes release H+ ions

Question 18

What are polymers?

Answer 18

Substance with a high RAM made by joining lots of small repeating units called monomers

Question 19

how are carboxylic acids formed

Answer 19

alcohol –oxygen -> carboxylic acids

Question 20

How do alkenes form polymers

Answer 20

They open up their double bonds and form bonds with other atoms to form long-chain molecules

Question 21

How do you name polymers

Answer 21

Add a poly in front of the monomer and put the monomer in brackets

Question 22

properties of poly(ethene)

Answer 22

flexible, electrical insulator, cheap

Question 23

uses of poly(ethene)

Answer 23

plastic bags, bottles

Question 24

properties of poly(propene)

Answer 24

flexible, strong, mouldable

Question 25

uses of poly(propene)

Answer 25

crates, ropes, furniture

Question 26

properties of PVC

Answer 26

tough, cheap

Question 27

uses of PVC

Answer 27

window frames, water pipes

Question 28

properties of PTFE

Answer 28

unreactive, tough, non stick

Question 29

uses of PTFE

Answer 29

non- stick pans, waterproof clothing

Question 30

Condensation Polymerisation

Answer 30

involves monomers with two different functional groups joining together to create polymer chains

Question 31

how is it different from addition polymerisation

Answer 31

• different functional groups
• a small molecule (e.g : water ) is lost each time they react

Question 32

ester link

Answer 32

formed when dicarboxylic ( 2 carboxylic acid ) and diol ( 2 alcohol ) molecules react ( O=C-O BOND)

Question 33

DNA

Answer 33

polymer made up of four different monomers called nucleotides

Question 34

proteins

Answer 34

polymers made up of repeating monomers called amino acids

Question 35

Carbohydrates

Answer 35

polymers made up of repeating monomers called sugars

Question 36

Raw material of polymers

Answer 36

Crude oil

Question 37

Why is the availability of this raw material a problem

Answer 37

It is non-renewable which means one day it will run out. The more crude oil we use, the more expensive it becomes due to its increasing scarcity

Question 38

Problems with disposing polymers in landfill sites

Answer 38

• valuable land is quickly used up for landfill sites
• most polymers are not biodegradable which means they just sit there for millions of years.
  -when it mixes with water it can produce a toxic substance called leachate which can harm the ecosystem

Question 39

Advantages of recycling polymers

Answer 39

• reduces amount of non biodegradable waste in landfills
• reduces emisions of greenhouse gases by burning polymers
• uses less resources than making new plastics
• reduces amount of crude oil needed
• saves money and creates jobs

Question 40

Disadvantages of recycling polymers

Answer 40

• they must be separated by type before they can be melted and reformed
• this is difficult and expensive
• mixed polymers could have reduced quality
• melting down polymers releases dangerous gases which can harm wildlife
• can only be done finite amount of times