Cracking

-some relavent bits from videos- comprehensive/important info there -summaries from each vid -one catch out qu/unuslanon strait forward qu from ques sections

During fractional distillation, oil is separated into…

• A: Bitumen

• B: Fuel Oil

• C: Lubricating Oil

• D: Diesel Oil

• E: Kerosene/Parfin

• F: Petrol/Gasoline

• G: Gases

As we go down the fractionating column, we get hydrocarbons with carbon chains that are…

longer

Why are shorter chain carbons more useful….

• more flammable/burn easier

• high energy output when burnt eg) burning a litre of petrol produces more energy than of bitumen.

Cracking is the process of…

• taking a sample from one of the big oil fractions/longer chain hydrocarbons and breaking them into smaller-chain hydrocarbons.

• Unlike most other reactions, cracking does not involve specific reactant creating specific products

Thermal cracking exposes long-chain alkanes to…….temperatures of ……(°C) and…… (atm/kPa)pressures.

• high

• 700→ 1000 ºC

• high

• 70 atm / 7000 kPa

When long-chain hydrocarbons are thermally cracked, they produce one …….. and one or more……

• alkane

• alkenes

Alkanes produced in thermal cracking are mainly…

linear

In addition, the …… produced in thermal cracking can be used to produce…

• alkenes

• platics

When we write a full equation for a thermal cracking reaction, we first write an……….. with the information that we’re given.

Second, we work out the of………. the hydrocarbon that is missing.

Third, we calculate the……… between the atoms in the products and the ……...

Fourth, we write out the full……… for the thermal cracking reaction.

• equation

• type

• difference

• reactants

• equation

At high temperatures, an unknown compound is converted into one molecule of ,C5​H10​, one molecule of C6​H14​ and one molecule of C8H16.

• ?→C5​H10​ + C6​H14​ +C8​H16​.

• C=19 H=40

• C19H14→ C5​H10​ + C6​H14​ +C8​H16​.

• IUPAC name of Reactant: Nonane

The process of breaking bonds is …….

Thats why we say thermal cracking requires lots of …..

As …… is needed from the……..

• endothermic

• heat energy

• energy

• surroundings (to break bonds)

sometmes thermal cracking can produce……

• branched alkanes

Catalytic cracking uses a ……catalyst.

It requires ….temperatures of…… degrees celsius and ……pressures of …..atm/……..kPa.

• zeolite

• high

• 525-700

• low

• 1 atm/ 100 kPa

Why is the zeolite catalyst hetrogenous

• the hydrocarbon is in the liquid phase (aq) and the catalyst is in the solid phase (s)

• therefore its bcs its in a different state than the reactants

what do catalyst do

increase rate of reaction by providing an alternate route/ lowering Ea

What is zeolite made of

• aluminum + silicone

• ‘aluminosillicate’

What are the products of catalytic cracking

• one or more cycloalkanes

• mainly branched alkanes

• aromatic compounds eg) benzene C6H6

When we write a full equation for a catalytic cracking reaction with an unknown product, we first write…….. an with the information that we’re given.

Second, we work out the…… of the hydrocarbon that is missing.

Third, we calculate the…… between the atoms in the products and the ……..

Fourth, we write out the full …….for the catalytic cracking reaction.

• equation

• type eg) branched alkane or cycloalkane

• difference

• reactants

• molecular formula equation

At high temperatures, C14​H30​ is catalytically cracked to form one molecule of cyclopropane, one other cycloalkane with 6 carbons and one alkane.

Give the IUPAC name of this alkane if it’s linear.

Give the IUPAC name of this alkane if it’s branched at the second carbon.

the missing product is a ‘branched’ alkane (given theres 2 cycloalkane) → C=5 H=12

• Pentane

• 2-methylbutane

catalytic cracking can’t never produce …

alkenes

The benefit of thermal cracking is that it also produces…

Which can be used in …

and mainly …… which are …. chained

BUT (disadvantage) requires …… & ……

menaing it can be …..

• alkenes

• plastics

• more valuble alkenes

• shorter

• high temperature

• high pressure

• costly (requires a lot of energy)

The benefit of catalytic cracking is that it uses …… which …. the rate of reaction and ….. by ‘……’

which allow the cracking to be …… & …….

requiring … energy due to …. temepratures and pressure in contast with thermal cracking

its main byproduct is ……. ……… which can be used as …..

BUT (disadvantage) requires …… to be constantly …..

menaing it can be …..

• zeolite

• lowers

• Ea

• providing an alternate route

• cheaper

• easier

• less

• lower

• branched alkanes

• fuels

• zeolite catalyst

• replaced

• costly

Other than cracking, give one common use of alkane X.

• Jet fuel or diesel or diesel oil or (motor) fuel or lubricant or lubricating oil or petrochemicals or kerosene or paraffin or central heating fuel or fuel oil