Alkanes from Crude Oil

Question 1

What is fractional distillation?

Answer 1

the process in which the different fractions in the crude oil mixture are separated using boiling points as a means of separating the fractions.

Question 2

what is cracking?

Answer 2

longer chain hydrocarbons are passed through a heated catalyst, usually zeolite, causing the large molecules to break into smaller, more useful ones.

Question 3

why is cracking important?

Answer 3

we have less use of longer chain hydrocarbons, so cracking allows us to make more useful fuels from less used hydrocarbons which do not burn as well.

Question 4

what is zeolite?

Answer 4

a compound of aluminium, silicon and oxygen.

Question 5

what is reforming?

Answer 5

converting straight chained hydrocarbons into branched chained or cyclic hydrocarbons by heating them with a catalyst, usually platinum

Question 6

why do need reforming?

Answer 6

straight chained hydrocarbons don’t burn evenly in an engine, while branched or cyclic hydrocarbons burn far more evenly

Question 7

which catalyst is used in reforming?

Answer 7

platinum

Question 8

what two products are formed in reforming?

Answer 8

newly arranged hydrocarbon and hydrogen

Question 9

most of our energy comes from

Answer 9

fossil fuels

Question 10

most compounds in crude oil and natural gas are

Answer 10

alkanes

Question 11

the three main processes used to convert crude oil into fuels are

Answer 11

fractional distillation
cracking
reforming

Question 12

crude oil is

Answer 12

a complex mixture of compounds, mostly hydrocarbons

Question 13

the typical number of fractions obtained from crude oil is

Answer 13

six

Question 14

fractionation is done in a

Answer 14

distillation column

Question 15

in fractional distillation, the crude oil is first

Answer 15

heated until most of it turns to vapour

Question 16

the column has what is called a

Answer 16

temperature gradient

Question 17

temperature gradient in the column means

Answer 17

it is cooler near the top and hotter at the bottom

Question 18

the vapour in the distillation column passes through a series of

Answer 18

bubble caps

Question 19

different fractions condense at different

Answer 19

heights in the column

Question 20

what kind of molecules collect at the bottom of the distillation column?

Answer 20

longer chained molecules with higher boiling temperatures

Question 21

near the top of the distillation column, …….and…………molecules collect

Answer 21

smaller and shorter chained molecules collect

Question 22

some hydrocarbons in crude oil are

Answer 22

gases, so do not condense in the distillation column

Question 23

some fractions may contain different

Answer 23

compounds, so may undergo further distillation