C7-organic Chemistry Flashcards
(23 cards)
What does homologous series mean?
A group of chemicals which have similar properties and react similar ways.
What happens when the length of the carbon chain increases?
The boiling points increase, less flammable, less volatile
What are alkanes with more than four carbons at room temperature?
Liquids
What is combustion?
Another name for burning. In a combustion reaction fuel is burned and reacts with oxygen to release energy energy.
What happens to hydrogen and carbon in a complete combustion reaction?
They become oxidised (combined with oxygen)
What type of reaction is complete combustion?
An exothermic reaction
What is the word equation for complete combustion?
Hydrocarbon + oxygen = carbon dioxide + water
What is a petrochemical?
All the substances that you produce from crude oil
What is feedstock and what can it be used for?
Raw materials for the petrol chemical industry. Used for solvents, lubricant, polymers, detergents.
What type of reaction is cracking?
Thermal decomposition reaction (breaking down molecules by heating them)
What are the two methods of cracking?
Catalytic cracking and steam cracking
What is catalytic cracking?
1-heat long chain hydrocarbon and vaporise them
2-vapour can be passed over a hot powder powdered aluminium oxide catalyst
3-when long hydrocarbons come into contact with the catalyst they would split into two smaller hydrocarbons.
Steam cracking
1-heat long chain hydrocarbons and vaporise them
2-vaporised hydrocarbons are mixed with steam and heated to a very high temperature
3-this causes long hydrocarbon chain to split apart into shorter ones.
What are more reactive alkanes or alkenes?
Alkenes
What is the test used to test for alkenes?
Bromine water
-When orange bromine water is added to an alkene it will decolourise the bromine water from orange to colourless.
What is a polymer?
A long chain molecule that is formed by joining lots of smaller molecules (monomers) together
What can alkenes make when they are added together?
Polymers
What do addition polymerisation reactions require?
High pressure, a catalyst
Describe the combustion of hydrocarbons (there are three)
-exothermic reaction occurring when hydrocarbons are reacted with oxygen
-Complete combustion produces carbon dioxide and water (carbon and hydrogen atoms are completely oxidised).
-incomplete combustion produces carbon or carbon monoxide and water
What does saturated mean when referring to alkenes and alkanes?
Saturated compounds (alkanes) habe molecules in which all carbon-carbon bonds are single bonds. Alkenes are not saturated.
Describe the combustion of alkenes
They burn with smoky flames due to incomplete combustion.
What is an alcohol?
An organic compound that contains an -OH functional group.
How do molecules containing C=C bond form polymers?
C=C bonds open up and many smaller molecules (monomers) join together to form a chain (a polymer). No other products are made. It’s called an addition polymerisation reaction.
