C9(Crude Oil And Fuels)

Question 1

What is crude oil

Answer 1

A mixture of many different carbon compounds

Question 2

What are Alkanes

Answer 2

-saturated hydrocarbons
-All the carbon-carbon bonds are single covalent bonds
-They contain as many hydrogen atoms as possible in each molecule

Question 3

What are the 4 alkanes

Answer 3

Question 4

What is general formula for Alkanes

Answer 4

Question 5

Crude oil is separated into …

Answer 5

-Fractions using fractional distillation
-The properties of each fraction depend on the size of the hydrocarbon molecules in it

Question 6

Lighter fractions make better ..

Answer 6

-Fuels as they ignite more easily and burn well with cleaner flames

Question 7

What are the properties of short chain hydrocarbons

Answer 7

-low boiling point
-higher volatility
-low viscosity
-higher flammability

Question 8

What are the properties of long chain hydrocarbons

Answer 8

-high boiling point
-low volatility
-high viscosity
-low flammability

Question 9

Example of fractional distillation

Answer 9

Question 10

When hydrocarbons burn in plenty of air they …

Answer 10

Transfer lots of energy to the surroundings

Question 11

What is complete combustion

Answer 11

When a hydrocarbon burns with a rich supply of oxygen

Question 12

What does complete combustion produce

Answer 12

-carbon dioxide
-water

Question 13

What is incomplete combustion

Answer 13

When a hydrocarbon burns with a limited supply of oxygen

Question 14

What does incomplete combustion produce

Answer 14

-carbon dioxide
-carbon monoxide
-carbon(soot)

Question 15

What are 3 tests for gases formed in complete combustion

Answer 15

-carbon dioxide turns limewater cloudy
-water turns blue copper chloride pink
-oxygen relight a splint

Question 16

In complete combustion carbon and hydrogen are ..

Answer 16

Oxidised completely when they burn like this

Question 17

What is cracking

Answer 17

-a heavy fraction distilled from crude oil is heated to vaporise the hydrocarbons
-the vapour is then either passed over a hot catalyst or mixed with steam and heated to a very high temperature
-the hydrocarbons are cracked as thermal decomposition reactions take place
-the large molecules split apart to form smaller, more useful ones

Question 18

What is an example of cracking

Answer 18

Long chain hydrocarbon —> alkane + alkene + alkene

Question 19

What are Alkenes

Answer 19

-unsaturated hydrocarbons
-contain at least one double bond between their carbon atoms
-as carbon atoms form four covalent bonds it means that alkenes have two fewer hydrogen atoms in their molecules than alkanes

Question 20

Alkenes are more reactive than …

Answer 20

Alkanes

Question 21

What is the test for Alkenes

Answer 21

-alkenes react with orange bromine water
-if alkenes are present the orange bromine water will turn colourless
-alkanes do not react with bromine water

Question 22

What are the properties of alkenes

Answer 22

-burn in air(but not as well as small alkanes)
-react with bromine water, decolourising it

Question 23

Answer 23

Question 24

Answer 24

Question 25

Answer 25