Chapter C9 - Crude Oil and Fuels

Question 1

Describe a positive test for each of the products of combustion (2)

Answer 1

Carbon dioxide - Limewater cloudy Oxygen - Relight a glowing splint

Question 2

Properties of short chain hydrocarbons (4)

Answer 2

• Lower BP - Higher volatility - Low viscosity - Higher flammability

Question 3

What is a hydrocarbon (2)

Answer 3

• A compound - Containing only hydrogen and carbon atoms

Question 4

Crude oil is heated to vaporise the hydrocarbons. The vapour is then either (2)

Answer 4

• Passed over a hot catalyst - Mixed with steam and heated to a very high temperature

Question 5

Why do lighter fractions make better fuels (2)

Answer 5

• Ignite more easily - Burn well, with clean flames

Question 6

What is a finite resource (1)

Answer 6

A resource that can run out

Question 7

What reactions take place as hydrocarbons are cracked (1)

Answer 7

• thermal decomposition

Question 8

What is the formula for propane and butane (2)

Answer 8

Propane - C3H8 Butane - C4H10

Question 9

Label the products coming from the fractionating column and describe a use (10)

Answer 9

TOP TO BOTTOM

refinery/petroleum gas (camping gas)

gasoline/petrol (car engines)

kerosene (aircraft fuel)

diesel oil/gas oil (fuel in engines)

residue (making roads)

Question 10

Draw the display formula for butene (1)

Answer 10

Question 11

what is the positive test for an unsaturated hydrocarbon (1)

Answer 11

Turns orange bromine water colourless

Question 12

What is the general formula for alkanes (1)

Answer 12

2n+2

Question 13

Are hydrocarbons at the top of the column small or large molecules, and are they liquids or gases (2)

Answer 13

• small - gas

Question 14

What temperature is a fractionating column heated to (1)

Answer 14

350 degrees

Question 15

Draw the display formula for ethane (1)

Answer 15

..

Question 16

What are the products of the complete combustion of a hydrocarbon (2)

Answer 16

Carbon dioxide and water

Question 17

Properties of long chain hydrocarbons (4)

Answer 17

• Higher BP - Lower volatility - High viscosity - Smoky flame

Question 18

What is a saturated hydrocarbon (1)

Answer 18

• All the carbon-carbon bonds are single covalent bonds

Question 19

Why are alkenes unsaturated hydrocarbons (1)

Answer 19

Contain a C=C double bond

Question 20

What is cracking (1)

Answer 20

Breaking down large less useful hydrocarbon molecules into smaller, more useful ones

Question 21

What are the first four prefixes for alkanes (4)

Answer 21

Meth- Eth- Prop- But-

Question 22

Why are less useful hydrocarbon molecules cracked to form smaller ones (3)

Answer 22

• Thick liquids or solids with high boiling points - difficult to vaporise - do not burn easily, poor fuels

Question 23

Are alkanes saturated or unsaturated hydrocarbons (1)

Answer 23

Saturated

Question 24

propane + oxygen =

Answer 24

carbon dioxide + water