CHAPTER 9

Question 1

where is crude oil found

Answer 1

rocks

Question 2

how is crude oil made

Answer 2

remains of sea life were buried in mud and layers of rock build up on top
this create the high pressure and temperature needed for crude oil

Question 3

what conditions are needed for crude oil to form 3

Answer 3

no oxygen
high temperature
high pressure

Question 4

what is crude oil

Answer 4

a mixture of different carbon compounds

Question 5

what is a hydrocarbon

Answer 5

compounds containing carbon and hydrogen

Question 6

what is a fraction

Answer 6

different substances with similar boiling points found in crude oil

Question 7

formula and name of first alkane

Answer 7

methane CH4

Question 8

formula and name of second alkane

Answer 8

ethane C2H6

Question 9

formula and name of third alkane

Answer 9

propane C3H8

Question 10

formula and name of fourth alkane

Answer 10

butane C4H10

Question 11

how can you describe alkanes

Answer 11

saturated hydrocarbons

Question 12

what is a saturated hydrocarbon

Answer 12

it contains as many hydrogen atoms as possible in each molecule

Question 13

general formul of alkane

Answer 13

Cn H(2n+2)

Question 14

which hydrocarbon burns and ignites best

Answer 14

short chain hydrocarbons

Question 15

as the chain length increases, what happens to the boiling point of a hydrocarbon

Answer 15

it increases

Question 16

as the chain length increases what happens to the velocity of a hydrocarbon

Answer 16

it decreases

Question 17

what is the volality of a hydrocarbon

Answer 17

the tendency of a substance to turn into a gas

Question 18

as the chain length increase what happens to the viscosity of a hydrocarbo

Answer 18

it gets thicker

higher viscosity

Question 19

what is the viscosity of a substance

Answer 19

how easily it flows

Question 20

what do the properties of each fraction depend on

Answer 20

the size of the hydrocarbon molecules in it

Question 21

process of fractional distillation of crude oil

Answer 21

it is heated at the bottom of a tall column which is cooler at the top
the gases move up the column when they reach their boiling point they condense at the cooler temperature
they condense at different levels so can be connected

Question 22

what are the products of complete combustion of hydrocarbons

Answer 22

carbon dioxide and water

Question 23

when does incomplete combustion occur

Answer 23

when there isn’t enough oxygen

Question 24

what happens to the hydrocarbon when complete combustion occurs

Answer 24

they are oxidised to form the products

Question 25

what is produced when incomplete combustion occurs

Answer 25

carbon monoxide

Question 26

how to tell that a hydrocarbon is an alkane

Answer 26

it has a c-c single bond

Question 27

two tests for water

Answer 27

turns cobalt chloride paper pink

turns white anhydrous copper sulfate blue

Question 28

why are hydrocarbons cracked

Answer 28

the longer chainlengths aren’t in high demand but the shorter ones are so they are broken down to form these desirable chainlengths

Question 29

process of cracking

Answer 29

the fraction is heated to vaporise the hydrocarbons the vapour is then heated to a very high temperature
thermal decomposition takes place turning larger molecules into smaller molecules

Question 30

how to tell that a hydrocarbon is alkene

Answer 30

has a c=c double bond

Question 31

are alkenes saturated or unsaturated

Answer 31

unsaturated, compared to alkenes they have 2 less hydrocarbons for the carbon to bond to

Question 32

why are alkenes more reactive

Answer 32

the double bond opens up to form a single bond and allow the carbon to bond to other atoms

Question 33

general formula for alkenes

Answer 33

Cn H2n

Question 34

first four alkenes

Answer 34

ethene
propene
butene
pentene

Question 35

what happens when an alkene reacts with oxygen

Answer 35

if there is enough oxygen it will undergo complete combustion however alkenes are very likely to undergo incomplete combustion

Question 36

what is produced when an alkene undergos incomplete combustion

Answer 36

carbon carbon monoxide carbon dioxide and water

Question 37

what does the flame look like of something undergoing incomplete combustion

Answer 37

it will burn a smokey yellow flame

Question 38

what is the test for an unsaturated hydrocarbon

Answer 38

it turns orange bromine water colourless