C7

Question 1

What is a hydrocarbon

Answer 1

It is a molecule made up of only hydrogen and carbon atoms

Question 2

What is an alkane?

Answer 2

. Type of hydrocarbon
. Formula CnH2n+2
. Saturated- each carbon atom forms. 4covalent bond
. First 4 are methane, ethane, propane, butane

Question 3

What happens to hydrocarbons as they get longer?

Answer 3

Properties change-
. The shorter, the more runny it is
. The shorter, the lower boiling point it will have
. The shorter, the more flammable it is

Question 4

When does complete combustion occur?

Answer 4

When there is plenty of oxygen

Question 5

What is the equation for complete combustion and what occurs in complete combustion?

Answer 5

Equation-
Hydrocarbon + oxygen –> carbon dioxide + water
. Releases alot of energy
. During combustion, both hydrogen and carbon from hydrocarbon are oxidised
. Hydrocarbons are used as fuels due to the amount of energy they release when cumbust completely

Question 6

How is crude oil made

Answer 6

It is a fossil fuel. Formed from remains of plants and animals, mainly plankton, that died millions of years ago and were buried in mud. Due to high temps and pressure, remains turn into crude oil which can be drilled up and extracted

Question 7

What is a finite source?

Answer 7

Source that will run out

Question 8

What is fractional distillation used for and how does it work

Answer 8

. Used to seperate hydrocarbon fractions
. Crde oil is a mixture of lots of diferent hydrocarbons - mostly alkanes
. Oil heated until most of it has turned into gass. Gass enters the fractionating column
. There is a temp gradient in the column. Hot at bottom and cooler at top
. Longer hydrocarbons have higher boiling points so they condense back into liquid and drain out of bottom early on.
. Shorter hydrocarbons have lower boiling points. They condense and drain out later on near top of column

Question 9

What are some of the uses of crude oil

Answer 9

. Feul for vehicles eg - diesel oil
. Petrochemical industry

Question 10

What does cracking mean and why is it done

Answer 10

. Short chain hydrocarbon make good fuel but long chain hydrocarbon do not. Long chain hydrocarbon made from factional distillation is made into smaller chains through cracking process
. Cracking is a thermal decomposition reaction - breaking down molecules by heating them

Question 11

What are the 2 diferent methods of cracking and how do they work

Answer 11

. Catalytic cracking - heat long chain of hydrocarbon to vapourise them
Vapour passes over hot powdered aluminium oxcide catalyst. Long chain splits apart on surface of the specks of catalyst
. Steam cracking - vapourise hydrocarbon, mix with steam and heat at very high temp

Question 12

What are alkenes

Answer 12

. Hydrocarbon which contains a double bond between 2 of the carbon atoms
. The double bond means that the alkene has 2 less hydrogen atoms compared to the alkane and the same number of carbons so they are unsaturated
. The double bond can be opened up to make a single bond so carbon atoms can bond with other atoms, making them reactive

Question 13

Why are alkenes reactive?

Answer 13

The double bond can be opened up to make a single bond so carbon atoms can bond with other atoms, making them reactive

Question 14

What are the first 4 alkenes

Answer 14

Ethene, propene, butane, pentene

Question 15

What is the general formula for alkenes

Answer 15

CnH²n

Question 16

What is the equation for incomplete combustion

Answer 16

. Alkene + oxygen –> carbon monoxide + carbon dioxide + water
. Results in a yellow flame and less energy than complete

Question 17

How do alkenes react

Answer 17

Via addition reactions. Alkenes all have functional group c=c so they all react in similar ways. Double bonds open up and leave a single bond so a new attom can join

Question 18

What is it called when hydrogen react with alkene

Answer 18

Hydrogenation. H² is added double bond opens up

Question 19

What is produced when steam reacts with alkene

Answer 19

Alcohol - when alkene reacts with steam, water is added across the double bond and an alcohol is formed

Question 20

What do u call a halogen that has reacted with an alkene

Answer 20

Eg: bromine and ethene
Dibromoethane

Question 21

What is the test for alkenes

Answer 21

Add bromine water to Saturated compound. If alkene is present, the colour of the bromine water will turn from orange to colourless

Question 22

What hat are plastics made off

Answer 22

Long chain molecules called polymers. Polymers are long chains made up of monomers

Question 23

What are addition polymers

Answer 23

Long chain molecules made up of unsaturated monomers. These monomer shave a double covelent bond which can open up to allow other monomers to join on to create the polymer. This is called audition polymerisation

Question 24

What is the functional group of alcohol

Answer 24

-OH

Question 25

What are the properties of aclohol

Answer 25

. Flammable . Undergo complete combustion producing CO² and H²O . Neutral PH - soluble in water . Can react with Sodium - produce hydrogen . Can be oxidised - react with oxygen - to form carboxylic acid

Question 26

What some uses of alcohols

Answer 26

Used as solvents and fuels

Question 27

What is fermentation and what does it produce

Answer 27

It is when anearobic respiration occurs in yeast cells. It produces the alcohol ethanol and also CO²

Question 28

What are carboxylic acids

Answer 28

They are a homologous series of compounds that have the functional group -COOH. the names of them end in '-anoic acid'

Question 29

What do carboxylic acids react with to form salt, water and carbon dioxide

Answer 29

Carbonates

Question 30

What is the chemical equation for esters

Answer 30

Alcohol + carboxylic acid --> ester + water . Uses an acid catalyst

Question 31

What does condensation polymerisation create

Answer 31

Polymers

Question 32

What does condensation polymerisation invlove

Answer 32

Monomers which contain diferent functional groups

Question 33

How does condensation polymerisation work

Answer 33

Monomers react together and bonds form between them, making polymer chains. For each new bond that forms, a small molecule like water is lost

Question 34

What is the most simplest type of condensation polymerisation

Answer 34

These contain only 2 diferent types of monomers, each with 2 of the same functional group

Question 35

What is the number of types of monomers in addition polymerisation

Answer 35

Only one type containing c=c bond

Question 36

How many products are formed In addition polymerisation

Answer 36

Only one

Question 37

What is the munber of types of monomers in condensation polymerisation

Answer 37

2 monomer types each containing 2 of the same functional groups Or one monomer type with 2 diferent functional groups

Question 38

What do amino acids contain

Answer 38

An amino group and carboxylic group. Eg: glycine

Question 39

What are protien made up of

Answer 39

Polymers of amino acids

Question 40

What are DNA molecules made from

Answer 40

Nucleotide polymers