organic chemistry

Question 1

what is hydrocarbon

Answer 1

any compound that is formed from carbon and hydrogen atoms only

Question 2

what is a alkane

Answer 2

the simplest type of hydrocarbon you can get

Question 3

what is the general formula for alkanes

Answer 3

CnH2n+2

Question 4

Organic chemistry is about molecules that contain which element?

Answer 4

carbon

Question 5

do alkanes have single or double bonds

Answer 5

only single bonds

Question 6

what is a homologous series

Answer 6

a group of organic compounds that react in a similar way

Question 7

what type of series is alkanes apart of

Answer 7

homologous series

Question 8

what are the first four alkanes

Answer 8

methane,ethane,propane,butane

Question 9

what is the formula for methane

Answer 9

CH4

Question 10

what is the formula for ethane

Answer 10

C2H6

Question 11

what is the formula for propane

Answer 11

C3H8

Question 12

what is the formula for butane

Answer 12

C4H10

Question 13

what is the property of a hydrocarbon with a shorter carbon chain

Answer 13

• more runny
• less viscous ( gloopy)
• more flammable
  -more volatile ( turn into a gas at a lower temperature)
• lower boiling point

Question 14

what does volatile mean

Answer 14

it means it turns into a gas at a lower temperature

Question 15

What is the word equation for the complete combustion of a hydrocarbon?

Answer 15

hydrocarbon + oxygen ➔ carbon dioxide + water

Question 16

During a combustion reaction, are carbon and hydrogen oxidised or reduced?

Answer 16

oxidised
carbon becomes CO2
hydrogen becomes H2O
so both have gained oxygen

Question 17

Is combustion an exothermic or endothermic reaction?

Answer 17

exothermic

Question 18

what type of fuel is crude oil

Answer 18

a fossil fuel

Question 19

what are non-renewable fuels

Answer 19

fuels that take so long to make and their being used up faster than there being formed

Question 20

what si crude oil

Answer 20

a mixture of hydrocarbons which are mostly alkanes

Question 21

how can the different compounds be separated in crude oil

Answer 21

through fractional distilation

Question 22

how is crude oil formed

Answer 22

• dead plants and animals - mainly plankton
• these organic remains buried in the earth
• over millions of years the organic remains were compressed under heat and pressure
• the pressure and heat turns it into crude oil

Question 23

what are the steps in fractional distillation

Answer 23

• crude oil heated until turned to gas
• gas enter fractionating column
• temperature gradient in column ( hot at bottom cool at hot)
• longer hydrocarbons have higher boiling point so they will condense into liquids first at the bottom, shorter chains of hydrocarbons will condense near the top as it is cooler
• end up with crude oil mixture separated

Question 24

what are the types of fuel hydrocarbons can be used for

Answer 24

kerosene
petrol
diesel

Question 25

When separating crude oil we use a fractionating column. Is the top of the column hotter or cooler than the bottom?

Answer 25

cooler

Question 26

what is a feedstock

Answer 26

a raw material used to provide reactants for an industrial reaction.

Question 27

what is a petrochemical

Answer 27

a substance made from crude oil, via chemical reactions.

Question 28

what is cracking

Answer 28

the process in which larger chain hydrocarbons are split into smaller, more useful hydrocarbons.

Question 29

why are short chain hydrocarbons more useful than long chain ones

Answer 29

they are more flammable so they make good fuels

Question 30

What type of reaction is cracking?

Answer 30

thermal decomposition

Question 31

why is cracking a thermal decomposition reaction?

Answer 31

because it involves using heat to break something apart

Question 32

what are the different types of cracking

Answer 32

catalytic cracking steam cracking

Question 33

what happens in catalytic cracking

Answer 33

- heat the long chain hydrocarbon until it vaporises - the vapour can be passed over hot powdered aluminium oxide catalyst - the long chain molecules split apart on the surface of the catalysts

Question 34

what happens in steam cracking

Answer 34

- heat the long chain hydrocarbon until it vaporises - mix the vapour with steam and heat them to a very high temperature -this causes the long chain molecules to split apart

Question 35

as well as alkanes what else can cracking produce

Answer 35

alkenes

Question 36

what can alkenes be used for

Answer 36

used as a starting material when making lots of other compounds and can be used to make polymers

Question 37

do alkenes have a single or double bond

Answer 37

double bond

Question 38

what does cracking always produce

Answer 38

one alkane and one alkene

Question 39

does the double bond in alkenes make them more or less reactive

Answer 39

more

Question 40

what test can be done to test for alkenes?

Answer 40

the bromine water test

Question 41

what happens when the bromine water test is done on a alkane

Answer 41

no reaction will happen and it will stay bright orange

Question 42

what colour is bromine water orginally

Answer 42

orange

Question 43

what will happen when bromine water is added to a alkene

Answer 43

it will result in a colourless compound and the bromine water will be decolourised

Question 44

why does the bromine water react with alkenes instead of alkanes

Answer 44

because alkenes are more reactive as they have a double bond

Question 45

How is steam cracking different to catalytic cracking?

Answer 45

there is no catalyst involved in steam cracking

Question 46

what is the general formula for alkenes

Answer 46

CnH2n

Question 47

do saturated hydrocarbons have single or double bonds

Answer 47

single

Question 48

do unsaturated hydrocarbons have single or double bonds

Answer 48

double bonds

Question 49

are alkenes saturated or unsaturated

Answer 49

unsaturated

Question 50

are alkanes saturated or unsaturated

Answer 50

saturated

Question 51

Bitumen is a fraction that is removed near the base of the fractioning column. State one use of bitumen.

Answer 51

used to surface roads bitumen can be cracked into shorter chain hydrocarbons

Question 52

how is cracking different to fractional distiliation

Answer 52

cracking involves a catalyst distilation does not.

Question 53

what is the balanced symbol equation for the complete combustion of methane

Answer 53

CH4+ 2O2 -> Co2 + 2H20

Question 54

what type of substance is poly(propene)

Answer 54

polymer hydrocarbon