2nd PPE Chemistry Higher Revision

2nd PPE Chemistry Revision- Higher

Using Hydrocarbons as Fuels:

What are Hydrocarbons?

Molecules (Compunds) that Consist of Hydrogen and Carbon Atoms ONLY!

Each Carbon Atom has 4 Bonds

Alkanes:

Have Single Bond

Cn H2n+2

Methane   CH4 C= 1 H=1 x 2+2= 4

Ethane     C2H6

Propane    C3H8

Butane     C4H10

Monkeys Eat Peanut Butter

Alkenes:

Have Double Bonds

CnH2n

Ethene 

Propene

Butene

Fuels= Burn to Use= Combustion provides Energy

Combustion= Exothermic

Complete Combustion: 21% O2

Hydrocarbon+ Oxygen ---> HEAT + H20 + CO2

Con: H20 + CO2= Greenhouse= Global Warming

Incomplete Combution: 5% O2

Hydrocarbon+ 0.05 O2--->  CO + 2H20

Cons:

Lack of Oxygen + Produce CO= Dangerous Gas = No odour, colourles, Tasteless

Burning= Combustion

We Burn Alkanes because the Reaction Releases Energy  e.g. Light, Heat etc.

Alkanes React when it's Burned because of the Oxygen Present in Air

Fractional Distillation:

Seperate Mixture of Hydrocarbons (Crude Oil)

Short Chains:

Low Boiling Point

Low Viscocity

High Flammability

High Volatility

Long Chain:

High Boiling Point

High Viscocity

Low Flammability

Low Volatility

Longer Chains Condense @ Bottom

Shorter Chain Condense @ Top

because of their Boiling Points

6 Marker!

Crude oil is a Thick Black Liquid and is a Mixture of Hydrocarbons.

Each Fraction have Different Boiling Points therefore, they Seperate at Different Temperatures.

Oil is Heated in a Furnace at 450C so that Evaporates; some will be still Sluggy which is known as Bitumen.

The Fractionating Column has a…