Organic Chemistry Flashcards
What can carbon form and, as a result what should we do?
Carbon can form four covalent bonds, giving rise to many carbon compounds.
It is easier to study these compounds by grouping them together into a
homologous series.
What is a homologous series?
A homologous series is a family of organic molecules and each organic molecule in a homologous series:
they have same general formula
their molecular formulae differ by CH2
they show a gradual variation in physical properties, such as their boiling points.
they have similar chemical properties.
What is a hydrocarbon?
A molecule that only consists of hydrogen and carbon.
What are the 4 homologous series’ that are studied at GCSE?
Alkanes
Alkenes
Carboxylic acids
Alcohols
What is the general formula of the alkanes?
CnH2n+2
What state at room temperature are methane, ethane, propane, butane?
They are gases at room temperature.
What is the molecular formula of propane, butane, ethane, methane in order of smallest to biggest?
Methane: CH4
Ethane: C2H6
Propane: C3H8
Butane: C4H10
What is the structural formula of methane, ethane, propane, butane?
Methane:
H
|
H --- C --- H
|
H
Ethane:
H H
| |
H --- C --- C ---H
| |
H H
Propane:
H H H
| | |
H --- C --- C --- C --- H
| | |
H H H
Butane:
H H H H
| | | |
H --- C --- C --- C --- C --- H
| | | |
H H H H
What is crude oil?
Crude oil is:
A finite resource- once it’s used up it can’t be replaced in a human lifetime.
The main source of hydrocarbons.
Used as feedstock – the raw material – for the petrochemical industry.
What is fractional distillation?
Fractional distillation separates crude oil into simpler, more useful mixtures, because different hydrocarbons have different boiling points. Each simpler mixture is called a fraction. The fractions are largely mixtures of compounds of the formula CnH2n+2 which are members of the alkane homologous series.
What happens during fractional distillation?
During fractional distillation:
Heated crude oil enters a tall fractioning column, which is hot at the bottom and cooler at the top.
vapours from the oil rise through the column.
each fraction condenses when it becomes cool enough, each at a different point in the column.
pipes lead each fraction away.
Small hydrocarbon molecules have weak intermolecular forces, so they have low boiling points. They do not condense, but leave the top of the column as gases.
Long hydrocarbon molecules have stronger intermolecular forces, so they have higher boiling points. They leave the bottom of the column as hot, liquid bitumen.
What are the fractions produced in fractional distillation?
Refinery gases, petrol, naptha, kerosene, diesel, fuel oils, bitumen.
What are refinery gases used for?
Bottled gases.
What is petrol used for?
As a fuel for cars.
What is naphtha used for?
To manufacture chemicals and plastics.
