Carbon Compounds Flashcards
(14 cards)
Crude oil
Non renewable resource
Made from fossilised plankton
Found in rocks
Used to produce fuels and other chemicals
Mixture of lots of different compounds not chemicals combined
Most of the compounds are hydrocarbons- molecules made of only carbon and hydrogen
Properties of hydrocarbons
A hydrocarbons size effects its properties
Boiling points - longer chain hydrocarbons have higher boiling points
Viscosity - longer chain hydrocarbons have higher viscosity( thicker and flow less easily)
Flammability - hydrocarbons with longer chains are less flammable
Alkane structure
Each carbon bonds to 4 hydrogens
The bonds are all single bonds
CⁿH²ⁿ+²
Alkane uses
Fuels
First 4 alkanes
Methane
Ethane
Propane
Butane
What is fractional distillation
Process of separating crude oils into groups of hydrocarbons with similar numbers of carbon atoms.
These groups are called fractions
Different sized hydrocarbons have different boiling points so fractional distillation separates hydrocarbons using this
Process of fractional distillation
Evaporation - crude oil vapour is put in a fractioning column at the bottom and rises upwards
Condensation - temp is highest at the bottom of the column. Long chain molecules will condense at the bottom and are Collected as liquids
Shirt chain molecules pass up the column and condense at lower temps nearer the top
Collection - fractions are collected and processed to create end products eg fuels and detergents
What is a homologous series
A family of similar compounds
Alkenes
Alkanes
Alcohols
Carboxylic acids
Burning hydrocarbons
Equations for combustion of hydrocarbons depends on amount of energy available
Burning with plenty of oxygen - carbon and hydrogen oxidised to create carbon dioxide and water.
There’s a release of energy
Burning with lack of oxygen -
When alkane are burning without enough oxygen the carbon monoxide can be formed
Carbon monoxide is:
Toxic
Odourless
Colourless
Why do heavy fractions of crude oil not make good fuels
Don’t ignite easily
Have high boiling points
Have low volatility
What is cracking
Process that breaks down long chain hydrocarbons into shorter chain molecules that are more useful. It’s done two ways
Catalytic cracking
Vaporised heavy hydrocarbons are passed over top of a heated catalyst
Alkenes and alkanes are produced by this reaction
Steam cracking
Vaporised hydrocarbons are combined with steam in a high temperature environment
Alkanes and alkenes are produced this way
Uses of alkenes
Combine to make polymers
Used for starting materials for chemicals like ethanol
