C7

Question 1

Where do we find crude oil?

Answer 1

We find crude oil in rocks
Finite resource

Question 2

How is crude oil formed?

Answer 2

Crude oil is formed over millions of years from the remains of plankton, which were buried in mud

Question 3

What is crude oil?

Answer 3

Crude oil is a mixture of molecules called hydrocarbons

Question 4

What is a hydrocarbon?

Answer 4

A molecule containing hydrogen and carbon only

Question 5

What is the formula for Alkanes

Answer 5

C(n)H(2n)+2

Question 6

Why are alkanes saturated molecules

Answer 6

Carbon is fully bonded to the hydrogen

Question 7

How do we remember methane Ethane propane and butane?

Answer 7

My
Eggy
Poo
Burns

Question 8

What are the properties of hydrocarbons

Answer 8

• viscosity increases as size of hydrocarbon increases
  -flammability decreases as size of hydrocarbon increases
  -boiling point increases as size of hydrocarbon increased

Question 9

What happenes when hydrocarbon fuels combust

Answer 9

-Hydrocarbon fuels release energy when combusted
-carbon and hydrogen atoms react with oxygen and are oxidised

Question 10

how do we separate hydrocarbons

Answer 10

fractional distillation

Question 11

what happens in fractional distillation of crude oils?

Answer 11

-crude oil is heated to very high temperature
-crude oil vapour is fed into fractional distillation column
-column is hotter at bottom and cooler at top
-hydrocarbon vapours rise up the column
-hydrocarbons condense whn they reach bp
-liquid fractions are removed
-remaining hydrocarbons travel further up column
-they condense when they reach bp

Question 12

what is removed from the bottom of the columb

Answer 12

very long chain hydrocarbons

Question 13

what is removed from the top of the columb

Answer 13

very short hydrocarbon gases

Question 14

what are fractions used for

Answer 14

-some fractions are used as fuels
-some fractions are used as feedstock(chemical used to make other chemicals)

Question 15

what are fractions

Answer 15

fractions contain hydrocarbons with a similar number of carbon atoms

Question 16

what happens during cracking

Answer 16

a long chain alkane is broken down(cracked) to produce smaller and more useful molecules

Question 17

what is produced during the cracking of alkanes

Answer 17

shorter chain alkane

alkene

Question 18

what are the conditions for catalytic cracking

Answer 18

in catalytic cracking we use high temperatures and a catalyst

Question 19

what are the conditions for steam cracking

Answer 19

in steam cracking we use high temperatures and steam

Question 20

what do alkenes contain

Answer 20

alkenes have double covalent bond between two carbon atoms

Question 21

why are alkenes useful

Answer 21

-make polymers
-starting material for other chemicals

Question 22

what is the difference between alkanes and alkenes

Answer 22

alkenes contain a double covalent bond
alkenes are more reactive then alkanes

Question 23

how do we test for alkenes

Answer 23

-using bromine water(orange)
-if we shake the bromine water with our alkene it will turn colourless