C9 (Crude Oil)

Question 1

What is crude oil?

Answer 1

Mixture of different lengths of hydro carbons

Question 2

What is a hydrocarbon?

Answer 2

• a molecule only made up of hydrogen and carbon

- 1 carbon can bond with 4 hydrogens

Question 3

What is an Alkane with its general formula?

Answer 3

• single bond
• saturated hydro-carbon
• CnH(2n+2)

Question 4

What is an Alkene with its general formula?

Answer 4

• double bond which is much stronger
• unsaturated hydro-carbon
• Cn H(2n)

Question 5

What is the test to find out weather the hydrocarbon is saturated/unsaturated?

Answer 5

When you add bromine water to an alkene and it stays colourless, this means there is an existence of a double bond

Question 6

What are the physical properties of hydrocarbons? (The greater)

Answer 6

• greater the length the greater the boiling point as there are more bonds to change from a liquid to a gas
• greater the length the higher the viscosity (thickness)
• greater the length the lower the volatility (how easily it evaporates)
• greater the length the lower the flammability

Question 7

What is fractional distillation

Answer 7

Process where pure liquid is separated from a liquid mixture, using liquids of different boiling points

Question 8

5 fractions of the distillation column from bottom to top (with uses)

Answer 8

• bitumen (roads)
• kerosene (planes)
• diesel (car engines)
• paraffin (plane engines)
• petrol (car engines)

Question 9

How is crude oil distilled im the column

Answer 9

• hydrocarbons heated at a high temperature in order to change state
• as it enters the column the column has a gradient meaning it is cooler as you go up
• as the vapour moves up it compacts and changes back into liquid form
• size of the molecule determines which tray

Question 10

What is oxidation?

Answer 10

When you add oxygen to a chemical reaction

Question 11

What is complete combustion? (With a word equation)

Answer 11

• when carbon and hydrogen in the fuel are oxidised completely to burn
• lighter fractions are used as useful fuels when they burn in plenty of air they transfer a lot of energy to the surroundings
• propane + oxygen = carbon dioxide + water

Question 12

What is incomplete combustion?

Answer 12

• when there is not enough oxygen when the fossil fuels are burnt in the air
• tuen into carbon monoxide (co) which is colourless gas which is very toxic and enters the blood cells through red blood cells

Question 13

Why crack hydrocarbons

Answer 13

• large hydrocarbons molecules can be broken up into smaller molecules by passing vapours of a hot catalyst or mixing them with steam
• this produces saturated hydrocarbons used as fuels and unsaturated hydrocarbons (alkenes)

Question 14

Thermal decompostion

Answer 14

• this is what hydrocarbons are cracked as

- larger molecules are split for smaller molecules which are more useful

Question 15

What is the example of cracking?

Answer 15

• Decane is a medium sized alkane

- heated at 500 degrees as a catalyst which forms Pentane (used for petrol)