7 Organic 2 Flashcards
What is cracking?
The process of breaking down a long hydrocarbon into smaller hydrocarbons
What are the products of cracking?
Short alkanes and alkenes
Why is cracking important?
Because smaller hydrocarbons are more useful than longer ones
What are the two types of cracking?
Catalytic and steam cracking
What are alkenes
A different type of hydrocarbon which is more reactive than an alkane
What are alkenes used for?
As a starting material to make more useful chemicals
How do you test for an alkene?
React it with bromine water
What is the colour change when an alkene reacts with bromine water?
Turns from orange to colourless
What is an alkene?
A hydrocarbon with a double bond
What is the general formula for alkenes?
CnH2n
What does unsaturated means?
Contains double bonds (which could become C-H bonds)
What are the first four alkenes?
Ethene, propene, butene, pentene
What are the four reactions of alkenes?
Combustion, with water, with hydrogen and with halogens
How is the combustion of alkenes different to combustion of alkanes?
Alkenes usually react by incomplete combustion so burn with smoky flames
Why are the reactions of alkenes with hydrogen, water and halogens known as “addition” reactions?
Because new atoms are being added to the molecule by breaking the double bond
