Topic C7 - Organic Chemistry Flashcards
What is crude oil?
A mixture of hydrocarbons
A finite resource found in rocks and formed from dead plants and animals that have spent millions of years buried in mud
What is complete combustion?
An oxidation reaction that occurs when a fuel reacts with plenty of oxygen?
Why are hydrocarbons used as fuels?
Because combustion releases a lot of energy
What happens to the boiling point as the length of the hydrocarbon chain increases?
Boiling point increases
What happens to the viscosity as the length of the hydrocarbon chain increases?
Viscosity increases
What happens to the flammability as the length of the hydrocarbon chain increases?
Flammability Decreases
What is fractional distillation?
A process used to separate the hydrocarbons in crude oil into fractions according to their boiling points?
Where in the fractionating column do shorter hydrocarbons condense
Near the top, they have lower boiling points
Where in the fractionating column do longter hydrocarbons condense
Near the bottom, have higher boiling points
What are alkanes
Simplest type of hydrocarbons
Only 1 single covalent bond
Saturated
What is the general formula for the homologous series of alkanes?
CnH2n+2
What is cracking
Breaking down of long chain hydrocarbons into shorter more useful ones
What are alkenes used for?
To make polymers
A starting material for making other chemicals
What are the 2 types of cracking
Catalytic
Steam
What happens in catalytic cracking
Long chain hydrocarbons vapour used by heating
Hydrocarbon vapour is passed over a hot powdered aluminium catalyst
What happens in steam cracking?
Long chain hydrocarbons vapour used by heating
Hydrocarbon vapour mixed with steam and heated to a very high temperature
What’s more reactive: alkanes or alkenes
Alkenes are more reactive
How to test for an alkene
Add an alkene to bromine water, causes it to change from orange to colourless
What happens during combustion)
The carbon and hydrogen in the fuels are oxidised
The complete combustion of a hydrocarbon produces carbon dioxide and water
What is a homoglogous series?
Series of compounds with the same general formula, same functional groups and similar chemical properties
What type of reaction is cracking?
Thermal decomposition
Describe combustion of alkenes?
They burn with smoky flames due to incomplete combustion
What do addition reactions of alkenes do?
Addition atoms across the carbon carbon double bond so that the double bond becomes a single bind
