T6 - Organic Chemistry

Question 1

What is a hydrocarbon?

Answer 1

A molecule consisting of only carbon and hydrogen.

Question 2

Alkanes

Answer 2

Most basic type of organic molecule. The general formula for one is CₙH₂ₙ₋₂.

Question 3

Alkenes

Answer 3

Similar to alkanes except have a double carbon bond.

Question 4

Alcohol

Answer 4

Has a single carbon bond, also has a OH bonded to a carbon.

Question 5

Name all 7 types of reactions

Answer 5

Polymerisation, Addition, Hydrolysis, Substitution, Reduction, Oxidation and Eliminations

Question 6

What is polymerisation?

Answer 6

Joining smaller monomers together to form a very long chain

Question 7

What is addition?

Answer 7

Joining molecules together to form longer ones

Question 8

What is hydrolysis?

Answer 8

Splitting a molecule into 2 using a OH anion or H cation from a water molecule

Question 9

What is substitution?

Answer 9

Replacing one atom with another on a molecule

Question 10

What is reduction?

Answer 10

When a species gains electrons in a reaction

Question 11

What is oxidation?

Answer 11

When a species loses electrons in a reaction

Question 12

What is elimination?

Answer 12

Some atoms break away from a larger molecule

Question 13

What is a chemical mechanism?

Answer 13

Showing the movement of electrons during a chemical reaction

Question 14

What is radical substitution?

Answer 14

Used in reacting halogens to alkanes to make halogenoalkanes

Question 15

What is electrophilic addition?

Answer 15

Used in adding halogens and hydrogen halides to alkenes to make halogenoalkanes

Question 16

What are the 3 types of structural isomers

Answer 16

1. Chain, 2. Positional, 3. Functional group

Question 17

What is a structural isomer?

Answer 17

The same molecular formula but a different structural formula

Question 18

What are chain isomers?

Answer 18

Same molecular formula but different arrangement of the carbon skeleton

Question 19

What are positional isomers?

Answer 19

Same molecular formula but different position of the functional group on the carbon skeleton

Question 20

What are functional group isomers?

Answer 20

Same molecular formula but different functional group

Question 21

What are the two types of bond fission?

Answer 21

Homolytic and heterolytic

Question 22

What is bond fission?

Answer 22

The breaking of a covalent bond

Question 23

What is heterolytic fission?

Answer 23

When the covalent bond breaks the 2 electrons are distributed unequally all to one element to from a cation and an anion. A double headed arrow shows the movement of a pair of electrons.

Question 24

What is homolytic fission?

Answer 24

When the covalent bond breaks the pair of electrons in the bond are shared equally to form 2 uncharged radicals. 2 one-headed arrow is used to show movement of electrons. The dot on the element means there is an unpaired electron on the atom

Question 25

What are the 3 stages of free radical chain reactions

Answer 25

Initiation, Propagation, Termination

Question 26

Name some of the substances found in crude oil that can be fractionally distilled.

Answer 26

Diesel Oil, Fuel Oil, Kerosine, Gas, Petrol, Bitumen

Question 27

What are the 2 types of cracking?

Answer 27

Thermal cracking and catalytic cracking

Question 28

What is cracking and why do we do it?

Answer 28

Cracking is breaking long chain alkanes into shorter hydrocarbons. We do it because heavier fractions (long alkanes) are in low demand and lighter fractions like petrol are higher demand therefore more valuble.

Question 29

What are the conditions needed for thermal cracking?

Answer 29

1000 degrees celcius and 70atm of pressure

Question 30

What are the main products from thermal cracking?

Answer 30

Alkenes

Question 31

What are the conditions needed for catalytic cracking?

Answer 31

450 degrees celcius and slight pressure, and a zeolite catalyst to help lower the temperature needed

Question 32

Why are zeolite catalysts used in catalytic cracking?

Answer 32

It lowers the temperatures and pressure needed for cracking to occur, which lowers cost and speeds up the process

Question 33

What are the products of catalytic cracking?

Answer 33

Mainly aromatic hydrocarbons, that are useful for fuels for vechiles

Question 34

What is produced during the complete combustion of alkanes with plentiful oxygen?

Answer 34

Carbon dioxide and Water

Question 35

What is produced during the incomplete combustion of alkanes with limited oxygen?

Answer 35

Carbon monoxide and water

Question 36

What is produced during the incomplete combustion of alkanes with very limited oxygen?

Answer 36

Carbon (soot) and water

Question 37

Why is carbon monoxide bad and how can we remove it?

Answer 37

Carbon monoxide is poisonous as it bonds to haemoglobin in the blood instead of oxygen bonding, which disables the blood from delivering oxygen around the body and heart. We can remove it with a catalytic converter.

Question 38

Why is soot bad?

Answer 38

It can get into the lungs and cause breathing problems or lung cancer, make buildings dirty and can clog up engines

Question 39

Acid rain

Answer 39

Burning fossil fuels can release sulfur dioxide and oxides of nitrogen which contribute to acid rain

Question 40

What can acid rain do?

Answer 40

Acid rain can cause damage to plants, kill fish and cause erosion of buildings

Question 41

How does acid rain form from sulfur based impurities?

Answer 41

Some fossil fuels can contain sulfur based impurities, so when burned is released into the air and reacts with oxygen to produce sulfur dioxide. Sulfur dioxide is an acidic gas, which then reacts with water in the atmosphere to form sulfuric acid which falls as acid rain

Question 42

How does acid rain form from nitrogen?

Answer 42

Oxides of nitrogen are produced when nitrogen and and oxygen from the air are heated in the engine and react. The oxides of nitrogen then dissolve in the water in the atmosphere to form nitric acid which falls as acid rain

Question 43

Where are catalytic converters found and what do they do?

Answer 43

Catalytic converters are found mainly in vehicles and help to reduce the amount of unburnt hydrocarbons and oxides of nitrogen going into the atmosphere

Question 44

Why do people tend to try steal catalytic converters?

Answer 44

They contain expensive metals like platinum, rhodium and iridium metals

Question 45

What gases do catalytic converter convert and what are then converted into?

Answer 45

Harmful gases : Carbon monoxide, nitrogen oxides and unburnt hydrocarbons Less harmful gases: Water vapour, nitrogen and carbon dioxide

Question 46

Name 3 biofuels

Answer 46

Bioethanol, biodiesel and biogas

Question 47

How is bioethanol made?

Answer 47

Sugar from sugar cane is fermented to produced alcohols (ethanol) which can be used as a renewable fuel

Question 48

How is biodiesel made?

Answer 48

Made from refining oils and fats

Question 49

How is biogas made?

Answer 49

Make from break down of organic matter

Question 50

Advantages of biofuels?

Answer 50

- Biofuels are renewable so they are a more sustainable than crude oil - Biofuels produce carbon dioxide when they are burnt however they are classed as carbon neutral as the carbon dioxide is absorbed by the plants when its growing

Question 51

Disadvantages of biofuels?

Answer 51

- Expensive to convert existing petrol engines to take fuels with a higher concentration of ethanol - Land that could have been used to grow food is being used to make fuel. This could cause food shortages in countries that grow sugar cane

Question 52

Why are alkenes fairly reactive?

Answer 52

Double bonds have a high electron density and this makes alkenes fairly reactive

Question 53

Why is there restricted rotation in alkenes?

Answer 53

The carbons first bond is the sigma bond (which contains 2 electrons), and also has 2 sigma bonds between 2 hydrogens, leaving one delocalised electron in the p orbital. These p orbitals overlap, so the delocalised electrons can then be found in pi cloud of electron density. Since a p orbital is dumbbell shaped, there are pi clouds on either side, so it cannot rotate.