C7 - Organic Chemistry Flashcards
What is a hydrocarbon?
molecules made from both hydrogen and carbon.
What is crude oil made from?
crude oil is formed from dead plankton buried underwater and compressed over time. It consists mainly of hydrocarbons.
What are alkanes made from?
Made of single-covalently bonded carbon atoms surrounded by hydrogen atoms. ( Alkanes are saturated ).
What is the general formula for alkanes?
CnH2n+2,
CH4 (Methane)
C2H6 (Ethane)
C3H8 (Propane)
C4H10 (Butane)
What is fractional distillation used for?
It is used to separate hydrocarbons in crude oil so that they can be used.
How is fractional distillation used?
- Crude oil is heated up, and then enters the fractionating column where it evaporates, rising up the column, recondensing at different heights.
- Longer alkanes have higher boiling points due to more energy needed to overcome the strong intermolecular forces.
- It is colder further up the column, and hotter lower down.
Complete combustion
fuel + oxygen –> CO2 + water
Incomplete combustion
fuel + oxygen –> carbon monoxide/carbon + water
What are hydrocarbons used for?
-Solvents, lubricants, detergents,
polymers (plastic), which is made from ALKENES not alkanes.
What is an ALKENE?
An alkene is a hydrocarbon with at least one double covalent bond, they are unsaturated.
What is the general formula for alkenes?
CnH2n
How do you test for alkenes?
If an alkene is present, it will turn bromine water from orange to colourless, due to the bromine atoms bonding to the alkene by breaking the double bond.
This molecule then becomes saturated.
(Water can also react with an alkene to make an alcohol)
What is cracking used for?
Used to break longer alkanes into shorter alkanes and alkenes to meet the demand for shorter alkanes.
What is catalytic cracking?
Catalytic cracking uses a zeolite catalyst at 550 degrees, it’s preferred in industries.
What is steam cracking?
Steam cracking uses no catalyst and a higher temperature at >800 degrees.
