Hydrocarbons

Question 1

The size of a hydrocarbon determines what?

Answer 1

Which fraction of crude oil it will turn into

Question 2

What are the physical properties of a hydrocarbon determined by?

Answer 2

Intermolecular forces

Hold chains together

Question 3

Do all hydrocarbons have similar numbers of carbon atoms

Answer 3

Yes

Question 4

Do intermolecular forces of attraction break more easily in big or smaller molecules ?

Answer 4

Smaller
Because forces are stronger between big molecules
More points along its length of a big molecule where force is strong enough to hold it in place
Higher boiling points

Question 5

Why do bigger molecules have stronger forces?

Answer 5

More points of contact

If overcome one force of attraction there will be others

Question 6

Do big or small molecules have higher boiling points?

Answer 6

Big
Longer hydrocarbons liquid

Smaller often gases
Easier to ignite

Question 7

What is viscosity?

Answer 7

Measures how easily a substance flows

Question 8

Are longer hydrocarbons thick or thin?

Answer 8

Thick like treacle

Shorter runnier

Question 9

Why do hydrocarbons make good fuels?

Answer 9

Because combustion reactions give out lots of energy

Exothermic

Question 10

What is produced when hydrocarbons are burned?

Answer 10

Carbon dioxide
Water
Complete combustion

Question 11

What is complete combustion?

Answer 11

Reactions of hydrocarbons produce only carbon dioxide and water

Question 12

What is incomplete combustion?

Answer 12

If not enough oxygen
Contain less oxygen
Carbon monoxide 
Toxic gas
Carbon or soot
Eg. Broken boiler

Question 13

When is carbon monoxide produced?

Answer 13

Incomplete combustion

Question 14

What happens to your body if you have a lack of oxygen?

Answer 14

Faint
Coma
Death

Question 15

What happens if you get carbon monoxide in your blood stream?

Answer 15

Stops blood cells carrying oxygen round body

Leads to fainting, coma, death

Question 16

What is produced during incomplete combustion?

Answer 16

Soot

Tiny particles of carbon

Question 17

What are the problems with soot?

Answer 17

Makes buildings look dirty
Reduces air quality
Respiratory problems

Question 18

What is an exothermic reaction?

Answer 18

Gives out energy to surroundings
Heat
Exo = exit

Question 19

What are endothermic reactions?

Answer 19

Takes in energy from surroundings

Fall in temperature

Question 20

Name 2 pollutants caused by incomplete combustion

Answer 20

Carbon monoxide

Soot

Question 21

What causes acid rain?

Answer 21

Sulfur dioxide

Question 22

How is acid rain made?

Answer 22

Fossil fuels burned
Release harmful gases sulfur dioxide and nitrogen oxide
Mixes with clouds to make sulfuric acid
Falls as acid rain

Question 23

What is chemical in acid rain?

Answer 23

Sulfuric acid

Question 24

What are the effects of acid rain?

Answer 24

Makes lakes acidic
Kills trees
Animals die
Damages limestone buildings
Makes metal corrode
Stone statues

Question 25

What is photochemical smog?

Answer 25

Air pollution Causes breathing difficulties Headaches and tiredness

Question 26

What kind of fuel is hydrogen?

Answer 26

Clean Renewable as obtained by water No nasty pollutants

Question 27

Why is hydrogen a renewable resource?

Answer 27

Obtained from water | Won’t run out

Question 28

What are cons of using hydrogen for fuel?

Answer 28

Need special expensive engine Uses energy from other sources Hard to store Not widely available

Question 29

What is cracking?

Answer 29

Crude oil fractions split into smaller molecules

Question 30

What happens to long saturated molecules during cracking?

Answer 30

Turn into shorter unsaturated molecules

Question 31

Cracking is a form of what

Answer 31

Thermal decomposition | One substance breaks down into two or more new ones

Question 32

What is used to speed up cracking process?

Answer 32

Catalyst

Question 33

What happens to covalent bonds during cracking?

Answer 33

Broken down

Question 34

Why does the process of cracking require lots of energy?

Answer 34

To break down covalent bonds

Question 35

What is greenhouse effect?

Answer 35

Helps to keep Earth warm

Question 36

What are greenhouse gases?

Answer 36

Absorb and reflect heat radiation

Question 37

Name 3 greenhouse gases

Answer 37

Carbon dioxide Water vapour Methane

Question 38

What happens if too many greenhouse gases?

Answer 38

Enhanced greenhouse effect More heat radiation absorbed Less goes back to space Causes atmosphere to heat up

Question 39

Give 2 reasons why increasing human population affects levels of CO2

Answer 39

More people breathing out CO2 More people means more energy needed for lighting heating cooking transport Increased burning of fossil fuels releases more CO2 Deforestation Less trees means less CO2

Question 40

Why has methane levels risen in recent years?

Answer 40

Human activity Farming Methane Produced by cattle

Question 41

What is global warming?

Answer 41

Average temperature of earth increased Climate change Can cause flooding by melting ice caps

Question 42

Give 2 ways to reduce CO2 emissions

Answer 42

``` Walking Cycling Not driving Turn central heating down Limit use of fossil fuels ```

Question 43

How could you test an unknown gas to see if it was oxygen?

Answer 43

It would relight a glowing splint

Question 44

Name gases given out by volcanoes

Answer 44

Carbon dioxide Methane Ammonia