C9.2 & C9.3 Crude Oil and Fuels (Fractional Distillation & Combustion)

Question 1

What is flammability

Answer 1

How easily a substance burns/combusts.

Question 2

Boiling point

Answer 2

The temperature at which a liquids turn into a gas and the temperature at which the gas condenses back into a liquid.

Question 3

Volatility

Answer 3

How easily a liquid turns into a gas.

Question 4

Viscosity

Answer 4

How easily a substance flows.

Question 5

Complete combustion

Answer 5

When alkanes are burnt in excess (plenty of) oxygen, all carbon and hydrogen will be oxidised to form carbon dioxide and water.

Question 6

Incomplete combustion

Answer 6

When alkanes are burnt in a limited supply of oxygen and the carbon is only partially oxidised to form carbon monoxide and water.

Question 7

What is the test for carbon dioxide?

Answer 7

Bubble the gas through limewater (aqueous solution of calcium hydroxide) which goes from colourless to cloudy.

Question 8

What is the test for water?

Answer 8

Anhydrous blue cobalt chloride paper goes pink.
Or…
Anhydrous white copper sulfate goes blue.

Question 9

What is carbon monoxide and how is it produced?

Answer 9

Carbon monoxide is a toxic, colourless and odourless gas produced when fossil fuels undergoes incomplete combustion.

Question 10

What is the name of the simplest alkane?

Answer 10

methane

Question 11

What is the molecular formula of propane?

Answer 11

C₃H₈

Question 12

What is the molecular formula of butane?

Answer 12

C₄H₁₀

Question 13

What is the molecular formula of ethane?

Answer 13

C₂H₆

Question 14

What is the molecular formula of decane?

Answer 14

C₁₀H₂₂

Question 15

What is the structural formula for pentane?

Answer 15

CH₃CH₂CH₂CH₂CH₃

Question 16

The balanced equation for the complete combustion of methane is…

Answer 16

CH₄ + 2O₂ —> CO₂ + 2 H₂O

Question 17

The balanced equation for the incomplete combustion of ethane is…

Answer 17

2C₂H₆ + 5 O₂ —> 4CO + 6 H₂O

Question 18

How does the length of the carbon chain affect the boiling point of the molecule?

Answer 18

The longer the carbon chain, the greater the surface area (and point of contact) resulting in greater intermolecular forces and the higher the boiling point.