P2: Organic Chemistry Flashcards
What is crude oil?
The remains of plankton and other living material buried in mud millions of years ago.
Where is crude oil found today?
Rocks, and people have to drill underground to get it.
Is crude oil finite or infinite?
A finite resource, meaning it will eventually run out.
What is crude oil made up of?
A mixture of different hydrocarbons
What is a hydrocarbon?
A compound made only from carbon and hydrogen atoms.
What is the general formula for alkanes?
C(n) H(2n+2)
What are alkanes?
Saturated hydrocarbons
What are the names of the first 4 alkanes?
Methane, ethane, propane and butane.
What are the hydrogen and carbon atoms connected by in alkanes?
Single covalent bonds.
What are the different groups of hydrocarbons called?
Fractions.
How are the different hydrocarbons separated in crude oil?
Fractional distillation.
Do long hydrocarbons have higher or lower boiling points?
Higher. As a result, long hydrocarbons condense nearer the bottom of the column.
What is the first step in fractional distillation?
Evaporate the crude oil by heating it. This causes most of the hydrocarbons to evaporate and rise up the fractional distillation column.
Do short hydrocarbons have lower or higher boiling points?
Lower. As a result, short hydrocarbons condense near the top of the fractional distillation column where it is cooler.
List some of the fuels that crude oil fractions are used as.
Petrol, diesel oil, kerosene, heavy fuel oil, liquified petroleum gas. Others are chemical products used in everyday life, such as solvents, lubricants, detergents and polymers.
What are alkenes?
Desaturated hydrocarbons. These are more reactive than alkanes.
Why are alkenes more reactive than alkanes?
Because of the presence of a double bond in alkenes.
What is the standard formula for alkenes?
C(n) H(2n)
How do you test for alkenes?
Place bromine water into the container with the alkenes. Bromine water changes from orange to colourless.
What can alkenes be used for?
Making polymers and a range of other chemical products.
Describe the properties of longer hydrocarbons.
They have higher boiling points, higher viscosity and low flammability.
Describe the properties of shorter hydrocarbons.
Lower boiling points, lower viscosity and high flammability.
What is the chemical term for burning?
Combustion
What happens when hydrocarbons combust?
Energy is released. This makes them useful as fuels.
What are the products of complete combustion?
Carbon dioxide and water.
Show the word equation of complete combustion of a hydrocarbon.
Hydrocarbon + Oxygen -(heat)—> Carbon Dioxide + Water
What is the name of the process to break down longer hydrocarbons?
Cracking
Why is cracking done?
To break longer hydrocarbons into smaller ones, and to meet the demand for fuel.
What are the two different methods of cracking?
Catalytic cracking and steam cracking.
What does catalytic cracking involve?
Passing the hydrocarbon over a hot catalyst at low pressure.
What are the products of cracking?
A mixture of smaller alkanes and alkenes.
What does steam cracking involve?
Long hydrocarbons reacting with steam at high temperatures.
What type of reaction is it when alkenes react with other reactants?
An addition reaction