Crude Oil And Fuels Flashcards
What is an atom?
The smallest part of an element that can exist.
What is an element?
A pure substance that cannot be broken down into other substances
What is a compound?
Two or more substances chemically bonded together
What is a covalent bond?
The bond between two or more atoms that share one or more pairs of electrons
What is organic chemistry?
The study of compounds containing carbon
What is crude oil?
A mixture of hydrocarbons, made from microorganisms over millions of years, and used in fuels and manufacturing. It is non-renewable because it is used at a faster rate than it is made.
What are hydrocarbons?
Compounds which contain hydrogen and carbon only
What are alkanes?
A group of saturated hydrocarbons with the general formula CnH2n+2
List the first four alkanes.
Methane, ethane, propane, butane
What is the displayed formula of propane?
H. H. H
H-C-C-C-H
H. H. H
What is the structural formula of propane?
CH3 CH2 CH3
What is fractional distillation?
A process used to separate the chemicals in crude oil into useful fractions.
Explain the process of fractional distillation.
The crude oil is heated in a furnace and passed into the bottom of a fractionating column. The vapour mixture given off rises up the
column and the different fractions condense out at different parts of the column. The fractions that come off near the top of the column are light-coloured runny liquids. Those removed near the bottom of the column are dark and treacle-like.
Why do the components of crude oil separate?
They have different boiling points
Why are boiling point and viscosity higher and volatility and flammability lower in larger molecule hydrocarbons
The intermolecular forces are stronger
From bottom to top, list the different layers of the fractionating column.
Fuel oil and residue, lubricants and waxes, petrol oil, kerosene, naptha, petrol, gases
What is combustion?
An oxidation chemical reaction where energy is released from fuels.
What happens when there is a limited supply of oxygen?
There is incomplete combustion-the products of combusting hydrocarbons are carbon monoxide and water.
What is the positive test for water as a product of combustion?
Turns the cobalt chloride paper from blue to pink
What is the positive test for carbon dioxide as a product of combustion?
Turns limewater cloudy
How is carbon dioxide formed and what are its issues?
Complete combustion of C in fuel
Greenhouse gas causing climate change
How is carbon monoxide formed and what are its issues?
Incomplete combustion of C in fuel
Toxic
How is carbon formed in combustion and what are its issues?
Incomplete combustion of C in fuel
Blackens buildings
Global dimming
How is sulfur dioxide formed and what are its issues?
Combustion of S in fuel
Acid rain
Now is nitrogen oxide formed and what are its issues?
Reaction of N2 with O2 at very high temperatures
Acid rain
Why do we use cracking?
Crude oil often contains too many large hydrocarbon molecules and not enough small hydrocarbon molecules to meet demand
What does cracking do?
It allows large hydrocarbon molecules to be broken down into smaller, more useful molecules.
How does cracking work?
Fractions containing large hydrocarbon molecules are vaporised and passed over a hot catalyst, such as ceramic. This breaks chemical bonds in the molecules, and forms smaller hydrocarbon molecules.
What is the positive test for alkenes?
Turns bromine water from orange to colourless
What is the general formula for alkenes?
CnH2n
