Hydrocarbons + Alkanes + Cracking

What is crude oil?

A finite resource found in the Earth’s crust.

What is crude oil made from?

Remains of organisms that lived and died millions of years go.

What is crude oil a mixture of?

Hydrocarbons that are joined in chains.

What is a hydrocarbon?

A compound made up only of carbon and hydrogen.

What are the fractions of the fractional distillation from top to bottom?

LPG, petrol, kerosene, diesel, heavy fuel oils, bitumen.

What are the uses of crude oil?

Feedstock for the petrol chemical industry.

What are feedstocks?

Raw materials used to provide reactants for industrial reactions.

What is fractional distillation useful for?

To separate crude oil in to different fractions.

Why does fractional distillation work?

Hydrocarbons have different boiling points.

What is the process of fractional distillation?

Heated crude oil enters a tall fractional column which is hottest at the bottom and coolest at the top, the vapours from the oil rise up through the columns and the vapours condense at the different fractions.

Why do small molecules have low boiling points?

They have weak intermolecular forces between molecules so don’t condense.

How does volatility change up the column?

They become increasing volatile as you go up the column.

How does ease of ignition change up the column?

They become easier to ignite as you go up the column.

How does viscosity (how easy to flow) change up the column?

They become less viscous as you go up the column.

What does being a larger molecule mean?

More intermolecular forces of attraction so molecules are held together stronger meaning they are more viscous, have higher boiling points, are less flammable and volatile.

What is the formula or alkanes?

CnH2n+2

How are hydrocarbons bonded?

Covalently by sharing electrons.

What happens if you mix an alkane and bromine?

The bromine stays orange/

What is the acronym for remembering the fractions?

Lazy Penguins Keep Drinking Hot Beer

What type of combustion do hydrocarbons undergo?

Complete and incomplete depending on availability of oxygen?

Is complete combustion endothermic or exothermic?

Exothermic

Why are alkanes saturated?

The carbon atoms are joined by single c-c bonds.

What are the first 5 alkanes?

Methane, ethane, propane, butane, pentane.

What is cracking?

Larger saturated hydrocarbon molecules are broken down into smaller more useful hydrocarbon molecules.

What are the starting reactants of cracking?

Alkanes

What are the two types of cracking?

Catalytic and steam.

What are the products of cracking?

An alkane and an alkene.

What are the conditions of catalytic cracking?

550c and a catalyst .

What is the process of catalytic cracking?

Vaporise the alkanes then pass the alkane over a catalyst.

What are the conditions of steam cracking?

800 c and no catalyst

What is cracking important for?

Helping match the supply of fractions to the demand and produces alkenes useful for feedstock and petrochemical industry.