Chemistry - ORGANIC CHEMISTRY (C7)

Crude Oil & Hydrocarbons -

What is crude oil?

A finite resource made from the remians of ancient biomass (mainly plankton) buried in mud over millions of years.

Crude Oil & Hydrocarbons -

What is a hydrocarbon?

A compound made only of hydrogen + carbon atoms.

Crude Oil & Hydrocarbons -

What is the general formula for alkanes?

CₙH₂ₙ₊₂

Crude Oil & Hydrocarbons -

What type of bonds do alkanes have?

Single covalent bonds (saturated).

Crude Oil & Hydrocarbons -

What is meant by a “saturated” hydrocarbon?

It contains only single bonds between carbon atoms.

Combustion of Hydrocarbons -

What are the products of complete combustion of hydrocarbons?

Carbon dioxide + water

Combustion of Hydrocarbons -

What are the products of incomplete combustion?

Carbon monoxide (/ carbon/soot) + water

Combustion of Hydrocarbons -

Why is carbon monoxide dangerous?

It’s a toxic gas that prevents the blood from carrying oxygen.

Fractional Distillation -

What is fractional distillation used for?

To separate the different hydrocarbons in crude oil based on boiling points.

Fractional Distillation -

What are the fractions in crude oil used for?

Fuels + feedstock for petrochemical industry.

Fractional Distillation -

What is the trend in boiling points in fractional distillation?

Longer chains = higher boiling points

Fractional Distillation -

What is the trend in viscosity + flammability of hydrocarbons?

Longer chains = more viscous, less flammable

Shorter chains = less viscous, more flammable

Cracking -

What is cracking?

Breaking long-chain alkanes into shorter alkanes + alkenes.

Cracking -

Why is cracking done?

To produce more useful hydrocarbons like short-chain alkanes + alkenes for fuels + plastics.

Cracking -

What are the two types of cracking?

Catalytic cracking and Steam cracking.

Cracking -

What is the test for alkenes (unsaturation)?

Add bromine water - it turns from orange to colourless.

Alkenes -

What is the general formula for alkenes?

CₙH₂ₙ

Alkenes -

What type of bonds do alkenes contain?

At least one double bond (C=C), making them unsaturated.

Alkenes -

Are alkenes more / less reactive than alkanes?

More reactive due to the double bond.

Alkenes -

Name the first four alkenes.

• Ethene

• Propene

• Butene

• Pentene

Uses of Hydrocarbons -

What are alkenes mainly used for?

Making plastics (polymers) + other chemicals.

Uses of Hydrocarbons -

What are short-chain hydrocarbons useful for?

Fuels - they ignite easily + flow well.

Uses of Hydrocarbons -

What industry heavily relies on hydrocarbons?

The petrochemical industry (for solvents, lubricants, detergents, etc.).