5th Form Mocks- Alkanes + Alkenes

Question 1

what is crude oil

Answer 1

mixture of hydrocarbons

Question 2

fractionating column products

Ravenous Pigs Keenly Devour Lettuce For Breakfast

Answer 2

Refinery gasses
Petrol
Kerosene
Diesel
Lubricating oil
Fuel heavy oil
Bitumen

Question 3

uses of fraction

Answer 3

Refinery gasses- domestic heating + cooking
Petrol - car fuel
Kerosine - plane fuel
Diesel - lorry fuel
Lubricating oil-
Fuel heavy oil - ship fuel
Bitumen- tarmacking roads

Question 4

what is the process that separates crude oil into fractions

Answer 4

fractional distillation

Question 5

describe the process of fraction distillation

Answer 5

1. oil is heated = most of it turns into gas
2. gasses enter fractioning column ( liquid bit, bitumen, is drained off at the bottom)
3. fractioning column = temp. gradient ( hot at bottom + gets gradually cooler as you go up)
4. when substance that make up crude oil reach part of column where the temp. is lower than there boiling point the condense
5. longer hydrocarbon= high boiling points=condense + drain out of column early on near the bottom
6. shorter hydrocarbons= lower boiling points= condense + drain out much later on near the top where it is cooler

Question 6

in a fractioning column what stops the separated mixtures from running back down the column and remixing

Answer 6

bubble caps

Question 7

what do bubble caps in a fractionating column do

Answer 7

stops the separated mixtures from running back down the column and remixing

Question 8

what does fractional distillation of crude oil produce in term of hydrocarbons

Answer 8

produces more long- chain hydrocarbons that can be used directly and fewer short-chain hydrocarbons than are required

Question 9

definition of cracking

Answer 9

splitting up of long-chain hydrocarbons into more useful short chain molecules

Question 10

what is the reason for cracking

Answer 10

demand for short chain hydrocarbons ( eg octane- used in petrol) is much higher than for longer chain hydrocarbons

Question 11

what is cracking a form of

Answer 11

thermal decomposition

Question 12

definition of thermal decomposition

Answer 12

breaking molecules down into simple molecules by heating them

Question 13

what catalytic cracking used to convert

Answer 13

converts long chain alkanes to alkenes ( + shorter alkanes )

Question 14

what conditions are required for cracking

Answer 14

Heat= 600c - 700c

Catalyst= silica / aluminium oxide

Question 15

how is an addition polymer made

Answer 15

by the joining up of many small molecules called monomers

Question 16

why are polymers hard to dispose

Answer 16

they are inert= don’t react easily

Question 17

why are polymers inert

Answer 17

the carbon-carbon bonds are very strong and aren’t easily broken

Question 18

what does polymers being inert cause ( in terms of problems of disposal)

Answer 18

take a long time to biodegrade

Question 19

definition of biodegrade

Answer 19

be broken down by bacteria or other organism s

Question 20

what does polymers inability to biodegrade mean

Answer 20

if burry in a land fill site they will still be there years later

Question 21

what problems come with burning polymers (plastics)

Answer 21

release toxic gasses