Organic Chemistry Flashcards
What is crude oil?
A finite resource and mixture of many hydrocarbons found in rocks.
What is complete combustion?
An oxidation reaction that occurs when a fuel reacts with plenty oxygen.
[e.g. hydrocarbon + oxygen ⟶ carbon dioxide + water]
Why are hydrocarbon use as fuels?
Their combustion releases a lot of energy.
What happens as the length of hydrocarbon chain increases?
> the boiling increases.
the viscosity increases.
the flammability decreases.
What is fractional distillation?
A process used to separate the hydrocarbons in crude oil into fractions according to they boiling points.
What are alkanes?
The simplest type of hydrocarbon, containing only single covalent bonds as they’re saturated.
What is the number of atoms and formula, structure of methane?
NUMBER OF CARBON ATOMS ⟶ 1. FORMULA ⟶ CH₄. STRUCTURE ↳ H | H ⎯ C ⎯ H | H
What is the number of atoms and formula, structure of ethane?
NUMBER OF CARBON ATOMS ⟶ 2. FORMULA ⟶ C₂H₆. STRUCTURE ↳ H H | | H ⎯ C ⎯ C ⎯ H | | H H
What is the number of atoms and formula, structure of propane?
NUMBER OF ATOMS ⟶ 3. FORMULA ⟶ C₃H₈. STRUCTURE ↳ H H H | | | H ⎯ C ⎯ C ⎯ C ⎯ H | | | H H H
What is the number of atoms and formula, structure of butane?
NUMBER OF ATOMS ⟶ 4. FORMULA ⟶ C₄H₁₀. STRUCTURE ↳ H H H H | | | | H ⎯ C ⎯ C ⎯ C ⎯ C ⎯ H | | | | H H H H
What is meant by the term cracking in chemistry?
Breaks down long-chain hydrocarbons into shorter more useful ones.
[long-chain alkane ⟶ shorter-chain alkane + alkane]
Long-chain hydrocarbons are vaporised by heating. What are the two methods of cracking?
> catalysts cracking.
> steam cracking.
What happens during catalysts cracking?
Hydrocarbon vapour is passed over a hot powdered aluminium catalyst.
What happens during steam cracking?
Hydrocarbon vapour is mixed with steam and heated to a very high temperature.
What is crude oil made of?
It is the remains of an ancient biomass consisting mainly of plankton that was buried in the mud.
What are hydrocarbons?
Molecules made up of hydrogen and carbon atoms only.
What is the formula for the homologous series of alkenes?
CnH₂n+2
What are the first four members of the alkanes?
> methane.
ethane.
propane.
butane.
How can crude oil be separated?
Through fractional distillation.
What happens when crude oil goes through the process of fractional distillation?
Crude oil is heated up to evaporate into vapour and as the vapours rise up the column they undergo condensation at the molecules boiling point and turn back into a liquid fraction to be collected.
What happens as the hydrocarbon chain gets longer?
> boiling point increases.
viscosity increases.
flammability decreases.
What are some examples of the use of crude oil in everyday life?
> petrol. > diesel. > kerosene. > heavy fuel oil. > liquefied petroleum gases.
What does the complete combustion of hydrocarbons produce?
Carbon dioxide and water.
What is the equation for the complete combustion of methane?
CH₄+2O₂⟶CO₂+2H₂O