C14 - Organic chemistry

Question 1

What is a hydrocarbon

Answer 1

an organic compound made up of purely hydrogen and carbon

Question 2

what are the properties of short and long chained hydrocarbons

Answer 2

short chained: lower melting point, lower viscosity, more flammable
Long chained: Higher melting point, higher viscosity, less flammable

Question 3

Fractional distillation separates

Answer 3

crude oil into simpler, more useful mixtures.

Question 4

Naphtha (in between gasoline and kerosene) used for

Answer 4

making chemicals.

Question 5

Lubricating oil (in between fuel oil and bitumen) used for

Answer 5

lubricants, waxes and polishes.

Question 6

Petrol use

Answer 6

fuel for cars

Question 7

refinery gas use

Answer 7

domestic heating and cooking

Question 8

kerosene use

Answer 8

fuel for aircrafts

Question 9

Diesel oil use

Answer 9

cars and trains

Question 10

fuel oil use

Answer 10

fuel for ships and power stations

Question 11

Bitumen use

Answer 11

surfacing roads and roofs

Question 12

How does fractional distillation separate crude oils

Answer 12

it is heated in a furnace and passed into the bottom of a fractionating column. It gives off mixtures of vapors that rise up the column and different fractions condense at different heights in which the liquids are collected at trays.

Question 13

The homologous series is a series of

Answer 13

compounds with the same general formula and similar chemical properties

Question 14

The physical properties that can change in a homologous series

Answer 14

As chains get longer boiling points increase

Each new chain adds on another CH2

Question 15

why does the boiling point of hydrocarbons increase as chains get longer

Answer 15

because there are more and more intermolecular forces between the molecules (although weak still add up)

Question 16

what is the alkane molecular structure

Answer 16

carbon atoms are bonded to 4 other atoms (hydrogen or carbon)

Question 17

alkanes are called saturated hydrocarbons because

Answer 17

they only contain single bonds with other atoms

Question 18

Uses of alkanes

Answer 18

They are unreactive

they can burn well making them a good source for fuel

Question 19

General formula for alkane

Answer 19

CnH(2n+2) (For example: if hydrocarbon has 7 carbons than the formula is C7H16

Question 20

Alkanes will react with chlorine in the presence of a

Answer 20

UV light which activates the chlorine to react

Question 21

The reaction between alkane and chlorine is called

Answer 21

substitution reaction as one hydrogen atom in the hydrocarbon is replaced with one chlorine atom

Question 22

the products of a alkane chlorine reaction are

Answer 22

chloroalkane + hydrogen chloride

Question 23

What are the 4 smallest hydrocarbons in ascending order

Answer 23

methane, ethane, propane, butane

Question 24

In an abundant supply of air alkanes burn to form

Answer 24

CO2 + water and is called complete combustion of alkanes in which a blue flame will be present

Question 25

word and symbol equation for the complete combustion of alkanes

Answer 25

methane + oxygen ==> carbon dioxide + water | CH4(g) + 2O2(g) ==> CO2(g) + 2H2O(l)

Question 26

When oxygen supply is limited incomplete combustion occurs in which the presence of a

Answer 26

yellow flame to show that

Question 27

word and symbol equation for the incomplete combustion of alkanes

Answer 27

methane + oxygen ==> carbon + water | CH4(g) + O2(g) ==> C(g) + 2H2O(l)

Question 28

Incomplete combustion of hydrocarbon can be dangerous because it can produce

Answer 28

carbon monoxide which is poisonous

Question 29

Heavy Fractions of Crude Oil do not make good fuels as they

Answer 29

have low volatility, do not ignite easily and have high boiling points

Question 30

What is the process of cracking

Answer 30

breaking down long chains of hydrocarbons into smaller more useful molecules. It is an example of thermal decomposition

Question 31

What are the products of cracking

Answer 31

an alkane and an alkene

Question 32

What are the requirements to perform cracking

Answer 32

a higher temperature of around 600 - 700 C | a catalyst of silica or alumina

Question 33

Alkenes are another

Answer 33

homologous series which have similar chemical and physical properties that change gradually from one member to the next

Question 34

Alkenes are a functional group C=C meaning

Answer 34

they have a carbon-carbon double bond

Question 35

Properties and uses of alkenes

Answer 35

More reactive than alkanes General molecular formula of CnH2n They are unsaturated hydrocarbons because they contain a double bond between 2 C atoms Uses: Making polymers such as polythene Burn in oxygen to form CO2 and H2O and CO if oxygen is limited

Question 36

Alkenes are involved in

Answer 36

addition reactions

Question 37

Hydrogen can be added to an alkene to make an

Answer 37

alkane

Question 38

What are the requirements for an addition reaction between hydrogen and an alkene

Answer 38

A nickel catalyst 150 C temperature H2

Question 39

Word and symbol equation for addition reaction between hydrogen and an alkene

Answer 39

Ethene + hydrogen ==> ethane | C2H4 + H2 ==> C2H6

Question 40

What test could you use to distinguish alkenes from alkanes or saturated hydrocarbon from unsaturated hydrocarbon

Answer 40

Add bromine water to hydrocarbon. Alkanes will not react with it in which there will be no color change but an alkene will react with bromine turning the color from orange to colorless.

Question 41

What is the word equation for an addition reaction between bromine and alkene

Answer 41

Ethene + Bromine ==> 1,2 -dibromoethane | C2H4 + Br2 ==> C2H4Br2

Question 42

Ethene can also react with steam to form

Answer 42

ethanol

Question 43

What are the requirements for a reaction between steam and ethene

Answer 43

Phosphoric acid catalyst 300 C and 70 atm H20

Question 44

What is the word equation for an addition reaction between steam and ethene

Answer 44

ethene + steam ==> ethanol | C2H4 + H2O ==> C2H5OH

Question 45

what is an isomer

Answer 45

isomer is same molecular formula but different structural formula

Question 46

Alcohol properties and characteristics

Answer 46

functional group of alcohols is a hydroxyl group OH They can be dehydrated to form alkenes Ethanoic and butanoic acids react the same with metals meaning alcohols react similar ways General formula (CnH2n + 1 OH)

Question 47

Reactions of a ethanol with air forms

Answer 47

CO2 + H2O

Question 48

ethanol + oxygen ==> | C2H5OH + 3O2 ==>

Answer 48

carbon dioxide + water | 2CO2 + 3H2O

Question 49

Uses of ethanol

Answer 49

Solvent - such as in disinfectants and perfumes Fuel - such as cars Alcoholic drinks - such as wine, beer and spirits

Question 50

Ethanol can be made via

Answer 50

fermentation or addition of steam

Question 51

In fermentation the reactant involved is

Answer 51

sugar and yeast. The sugar can be from barley in beer making and grapes from wine making.

Question 52

Why is yeast used in fermentation

Answer 52

yeast contains an enzyme which acts as a catalyst breaking down the sugars in a much faster rate.

Question 53

What are the requirements for fermentation

Answer 53

Temperature of around 25 - 30 C some say 37 C

Question 54

What is the formula for sugar (glucose)

Answer 54

C6H12O6

Question 55

What is the word and symbol equation for fermentation

Answer 55

sugar ==> ethanol + carbon dioxide | C6H12O6 ==> 2C2H5OH + 2CO2

Question 56

What are the advantages and disadvantages of making ethanol from fermentation and from addition of steam

Answer 56

Fermentation: Plant sugars and renewable however creates waste products of CO2 Addition of steam: Fast and efficient however ethene is cracked from crude oil which is non-renewable and also requires a lot of energy.

Question 57

What is a polymer

Answer 57

a long chained molecule formed from small units called monomers

Question 58

Manufactured polymers are called

Answer 58

synthetic polymers

Question 59

Common synthetic polymers include

Answer 59

plastics such as polythene and fabrics using clothing from polyester or polyamide.

Question 60

What are the two types of synthetic polymers

Answer 60

addition and condensation polymers

Question 61

polymers are held by

Answer 61

strong covalent bonds but weak intermolecular forces

Question 62

Polymers melt easily because

Answer 62

there are weak intermolecular forces which can be broken down easily

Question 63

Alkenes are monomers used

Answer 63

in addition polymerization because they can open up their double bonded carbon atoms and attach to other molecules forming chains of monomers

Question 64

when ethene monomers undergo addition polymerization the product is

Answer 64

poly (ethene)

Question 65

Condensation polymers are polymers made up of

Answer 65

2 different monomers reacting together

Question 66

When the two monomers react in condensation polymers they expel a

Answer 66

small molecule which is water

Question 67

Nylon is a

Answer 67

common synthetic condensation polymer

Question 68

Nylon is made from a molecule with

Answer 68

carboxylic acid (COOH) and another molecule (NH2) and they react to form an amide link

Question 69

Show ethene in a symbol equation for addition polymerization

Answer 69

nCH2 = CH2 ==> [CH2CH2]n the n represents the repeating unit the double bond "=" breaks and is replaced with "[]"

Question 70

what is the difference between additional and condensation polymerization

Answer 70

additional polymerization results in the addition of many of the same monomers whilst condensation involves two different types of monomers which when reacted expel a molecule of water.