C7 - Organic Chemistry Flashcards
What is organic chemistry primarily concerned with?
Compounds that contain carbon
Define a hydrocarbon.
A compound formed from carbon and hydrogen atoms only
Is CH3COOCH3 a hydrocarbon? True or False.
False
What type of bonds do alkanes contain?
All C-C single bonds
What is the general formula for alkanes?
C_nH_(2n+2)
Name the first four alkanes.
- Methane: CH4
- Ethane: C2H6
- Propane: C3H8
- Butane: C4H10
What is a displayed formula?
A drawing showing all the atoms and bonds in a molecule
How do hydrocarbon properties change as the carbon chain gets longer?
They become less runny, less volatile, and less flammable
What is the relationship between carbon chain length and viscosity?
Shorter carbon chains are less viscous
What type of hydrocarbons are used as ‘bottled gases’?
Short chain hydrocarbons with lower boiling points
What is produced during the complete combustion of hydrocarbons?
- Carbon dioxide
- Water vapour
- Energy
Complete the equation: hydrocarbon + oxygen → ______ + water.
carbon dioxide
During combustion, what happens to carbon and hydrogen in hydrocarbons?
They are oxidised
What is the balanced equation for the complete combustion of methane (CH4)?
CH4 + 2O2 → CO2 + 2H2O
How many hydrogen atoms are in one molecule of methane?
Four
What is oxidation in the context of combustion?
The gain of oxygen
What is crude oil?
A fossil fuel formed from the remains of plants and animals, mainly plankton, buried in mud over millions of years.
Why are fossil fuels like coal, oil, and gas considered non-renewable?
They take so long to form that they are being used up much faster than they are being replenished.
What process is used to separate the different hydrocarbons in crude oil?
Fractional distillation.
What are hydrocarbons?
Molecules containing only hydrogen and carbon.
Describe the temperature gradient in a fractional distillation column.
It’s hot at the bottom and gets cooler as you go up.
Which hydrocarbons condense and drain out of the column early on during fractional distillation?
Longer hydrocarbons with high boiling points.
Which hydrocarbons condense and drain out later in the column?
Shorter hydrocarbons with lower boiling points.
What is LPG and what does it contain?
Liquefied Petroleum Gas, mostly containing propane and butane.
Fill in the blank: Crude oil is a _______ resource.
finite
What can crude oil be separated into using fractional distillation?
Different fractions containing hydrocarbons with similar numbers of carbon atoms.
What are the approximate number of carbon atoms in LPG?
~3
What is the approximate number of carbon atoms in petrol?
5-12
What is the approximate number of carbon atoms in kerosene?
~15
What is the approximate number of carbon atoms in diesel oil?
~20
What is the approximate number of carbon atoms in heavy fuel oil?
~40
What can crude oil be used for?
Heating oil, fuel oil, or lubricating oil.
What is bitumen?
A very heavy fraction of crude oil.
What is the significance of crude oil in modern civilization?
Crude oil has fueled modern civilization and transformed the world.
What are some products derived from crude oil?
Products from crude oil include:
* Heavy fuel oil
* LPG (liquid petroleum gas)
* Kerosene
* Petrochemicals
What role does the petrochemical industry play in relation to crude oil?
The petrochemical industry uses hydrocarbons from crude oil to make new compounds for use in things like polymers, solvents, lubricants, and detergents.
What are homologous series in the context of hydrocarbons?
Homologous series are groups of compounds with similar properties that can bond due to one carbon atom forming different groups.
What are two examples of homologous series?
Alkanes and alkenes.
What is cracking in relation to hydrocarbons?
Cracking is the process of splitting up long-chain hydrocarbons into shorter, more useful ones.
Why are short-chain hydrocarbons in high demand?
Short-chain hydrocarbons are flammable and make good fuels.
What types of products are produced from cracking?
Products of cracking include:
* Petrol for cars
* Paraffin for jet fuel
* Alkenes
How do alkenes differ from alkanes?
Alkenes are more reactive than alkanes and are used as starting materials for making other compounds and polymers.
What is the test for alkenes using bromine water?
When bromine water is added to an alkane, it stays bright orange; when added to an alkene, it becomes colourless.
What type of reaction is cracking?
Cracking is a thermal decomposition reaction.
What is the first step in the cracking process?
The first step is to heat long-chain hydrocarbons to vaporise them.
What is catalytic cracking?
Catalytic cracking involves passing vaporized long-chain hydrocarbons over a hot powdered aluminium oxide catalyst.
What is steam cracking?
Steam cracking is a method where vaporized hydrocarbons are mixed with steam and heated to a very high temperature.
Complete the following reaction: Long-chain hydrocarbon molecule + _______ = Shorter alkane molecule + alkene
alkene
Provide an example of a cracking reaction involving decane.
Decane (C10) can be cracked to produce octane (C8) and ethene (C2).
