Organic reactions

Question 1

Alkenes

Answer 1

Unsaturated hydrocarbons

Question 2

unsaturated

Answer 2

Has atleast one carbon carbon double bond

Question 3

general formula for alkenes

Answer 3

CnH2n

Question 4

First four alkenes

Answer 4

E- Ethene
P- Propene
B- Butene
P- Pentene

Question 5

How does alkenes have lots of reactions with different compounds

Answer 5

Their Double bond

Question 6

Hydrogenation

Answer 6

Alkene reacts with hydrogen to then make it saturated as double bond splits and turn into an alkane
- conditions= catalyst present

Question 7

Alkene reacting with steam

Answer 7

Alkene + Water –> alcohol (OH at the end)
- conditions= catalyst and high temperature

Question 8

Alcohol separation

Answer 8

1. After reaction takes place, the mixture is
   passed from reactor to condenser
2. Ethene has a lower BP than ethanol and H2O
   so both condenses whilst any unreacted
   ethene gas is recycled back into reactor
3. the alcohol can then be purified from the
   mixture by fractional distillation

Question 9

Alkene incomplete combustion

Answer 9

Alkene + Oxygen –> Carbon + Carbon monoxide (CO) + carbon dioxide + water
- smokey yellow flame
- less energy

Question 10

Alkenes burn with a _______ ______?

Answer 10

smokey flame

Question 11

Alkenes reacting with Halogens

Answer 11

di + halogen + alkane

Question 12

Name some halogens

Answer 12

• Bromine
• Iodine
• Chlorine

Question 13

Test for alkenes

Answer 13

add the alkene solution into a test tube with orange bromine water.

Question 14

Result for alkenes

Answer 14

Orange bromine water turns colourless

Question 15

Alcohols

Answer 15

• Homologous series (-OH)
• Ends with -OL

Question 16

What are the first 4 alcohols in the homologous series?

Answer 16

• Methanol
• Ethanol
• Propanol
• Butanol

Question 17

What is the general formula for alcohols?

Answer 17

CnH2n+1OH

Question 18

Properties of the first four alcohols

Answer 18

• flammable
• Soluble
• Oxidised to make carboxylic acids

Question 19

Flammability of alcohol

Answer 19

Can undergo complete combustion.
Alcohol+O2–>CO2+H2O

Question 20

Solubility of alcohol

Answer 20

Can dissolve in water to form a solution which will have a neutral pH

Question 21

Uses of alcohol

Answer 21

• Fuels as combustion releases a lot of energy
• Solvents in industry (often is an alternative of water when water can’t dissolve something like hydrocarbons and lipid compounds)

Question 22

What is ethanol?

Answer 22

An alcohol with the formula CH3CH2OH

Question 23

What are the three main uses of ethanol?

Answer 23

• Chemical feedstock to produce other organic compounds
• Biofuel (can be burned like petrol)
• Used in alcoholic drinks

Question 24

How can ethanol be produced

Answer 24

Reaction of ethane with steam (H2O)

Question 25

What type of reaction is Ethene + steam

Answer 25

Addition reaction

Question 26

What are the conditions to make ethanol

Answer 26

- catalyst (phosphoric acid) - high temp (300•C) - high pressure (60-70atm)

Question 27

What are the advantages of ethanol

Answer 27

-ethene is cheap -reaction is cheap and efficient

Question 28

Disadvantages of ethanol

Answer 28

- Ethan made from crude oil (non-renewable) so if it runs out it will become expensive

Question 29

What is fermentation

Answer 29

An anaerobic respiration of sugars, which uses enzyme in yeast, to convert sugars into ethanol and CO2

Question 30

What type of reaction is fermentation

Answer 30

Anaerobic respiration (respiration without oxygen)

Question 31

Fermentation conditions

Answer 31

- Fermentation tanks that have no oxygen so ethanol isn't oxidised to ethanoic acid - Yeast cells that contain natural occurring enzymes to catalyse reaction - Temp at 30-40 (37)

Question 32

Advantages of fermentation

Answer 32

- Sugars are renewable recourse so cant run out - Yeast easy to grow

Question 33

Disadvantages of fermentation

Answer 33

- Process is relatively slow (bc of enzymes) - Ethanol produced isnt pure (aqueous) so have to fractional distillation

Question 34

Fermentation equation

Answer 34

sugar --> ethanol + Carbon Dioxide C6H12O6 --> CH3CH2OH+ CO2

Question 35

Carboxylic acids

Answer 35

- Homologous series (-COOH) - End with -anoic acid

Question 36

First four Carboxylic acids

Answer 36

- Methanoic acid (HCOOH) - Ethanoic acid (CH3COOH - Propanoic acid (CH3CH2COOH) - Butanoic acid (CH3CH2CH2COOH)

Question 37

Carboxylic acid properties

Answer 37

- All carboxylic acids are weak acids. - Weak acids do not fully ionise in water. - This means that weak acids don't release all their hydrogen ions.

Question 38

Carboxylic acid equation when ionised

Answer 38

C2H5COOH (Equillibrium) C2H5COO- + H+ - the negative products end with (metal) (alkane)-anoate ion

Question 39

Carboxylic acid reacting with metal carbonate

Answer 39

Carboxylic acid + metal carbonate --> salt + water + carbon dioxide

Question 40

How are carboxylic acids made?

Answer 40

Oxidise an alcohol using an oxidising agent

Question 41

Carboxylic acid reactions

Answer 41

-Carboxylic acid + metal ➔ salt + hydrogen -Carboxylic acid + metal oxide ➔ salt + water -Carboxylic acid + metal hydroxide ➔ salt + water -Carboxylic acid + metal carbonate ➔ salt + water + carbon dioxide

Question 42

Esters

Answer 42

- Functional group -COO- somewhere in the middle of the molecule - Formed from carboxylic acid and alcohol

Question 43

Esters properties

Answer 43

- pleasant smell (sweet or fruity) - Volatile (evaporate easily)

Question 44

Uses of esters

Answer 44

- Food flavoring - Perfumes

Question 45

How are esters formed

Answer 45

Alcohol (loses H) + carboxylic acid (loses OH) --> ethyl thanoate + water - with acid catalyst (concetrated sulphuric acid(H2S4))